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The solar photocatalytic degradation of pulp and paper mill wastewater has been reported by several scientists. However, this is the first time we are reporting for solar photocatalytic hydrogen production from pulp and paper mill wastewater and simultaneous degradation of pollutants. In this work, CuO based photocatalysts and novel square type photocatalytic reactor of 5 L capacity were used. The result shows that the prepared photocatalysts are solar active, efficient in hydrogen recovery and pollutant degradation from the pulp and paper wastewater. The effects of catalyst loading, sacrificial agent, pollutant removal efficiency and stability check were investigated. At 0.25 g/L of CuO/Fe 2 O 3 , 0.2 M of sacrificial agent (Na 2 SO 3 2−) and hydrogen yield of 1000 mL from 1000 mL of wastewater was achieved. The removal efficiency of TSS, TDS, BOD, COD, turbidity and TOC are around 70, 50, 60, 65, 70 and 45% respectively. Reusability study revealed that CuO/Fe 2 O 3 was chemically stable and could be reused successively (five cycles) without significant changes in its photoactivity and intrinsic properties. [Display omitted] • Visible light active CuO mixed with novel metal oxides were employed. • Hydrogen recovery from black liquor, paper mill wastewater were 1000 mL/h/L and 850 mL/h/L. • Efficiency of degradation of pulp & paper wastewater chemicals were around 50–70%. • AcHieved high recovery of hydrogen from pulp & paper wastewater. [ABSTRACT FROM AUTHOR]

1 Amorphous carbon was facilely obtained via the treatment of waste papers with sulfuric acid. 2 The combination of amorphous carbon with graphitic carbon nitride leads to an increased photo-catalytic H 2 generation. 3 The enhancement in H 2 generation is resultant from the efficient separation of electrons and holes owing to the excellent electrical conductivity of amorphous carbon. Up-cycling of waste papers to value-added carbon products has significant environmental and economic benefits in real life. This work aims to recycle the waste papers to construct amorphous carbon modified graphitic carbon nitride composite photocatalysts for efficient photocatalytic hydrogen generation from water under visible light. Amorphous carbon (labeled as a-C) was yielded from the office waste papers by simple sulphuric-acid treatment and then combined with graphitic carbon nitride (g-CN) to form the g-CN/a-C composite photocatalysts by the thermolysis of a-C and melamine mixture. The addition of a-C enlarges the surface area of g-CN from 11.52 m2 g−1 of pristine g-CN to 28.12 m2 g−1 of g-CN/a-C-100. In addition, the a-C incorporation can significantly separate the electrons from the photoexcited g-CN owing to the excellent conductivity of a-C. As a result, an increased photocatalytic H 2 generation was realized under visible light exposure. The g-CN/a-C-100 sample with optimized a-C contents offers the highest photocatalytic H 2 generation rate of up to 17.1 μ mol h−1, which is ∼12 times higher than that of pristine g-CN under the same condition. The present study manifests the great potential of the recycling of office waste papers for increased photocatalytic H 2 generation. Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]

In this study, practical application for the industrial-scale hydrogen evolution reaction (HER) process is established using sustainable Cu 2 CoSnS 4 embedded in paper-working electrodes. The Cu 2 CoSnS 4 is produced using a solvent-free solid-phase approach. The effect of a wide pH range of electrolytes on working electrodes for hydrogen evolution reactions is also investigated. The Cu 2 CoSnS 4 embedded paper-working electrodes exhibit goodelectrocatalytic activity for hydrogen evolution reaction with low overpotential values of 233, 310, and 261 mV vs RHE at 10 mA/cm 2 in 0.5 M H 2 SO 4 ,1 M KOH, and 1 M PBS, respectively. These designed electrodes exhibit high double-layer capacitance and electrochemical surface area for a wide pH range. In acidic, alkaline and neutral environments, the catalyst-embedded paper electrodes explicit high turnover frequencies of 2.15 s−1, 2.75 s−1, and 2.11 s−1, respectively. The temperature-dependent hydrogen evolution reaction is studied to calculate the activation energy of the cathodic electrode. Utilising chrono-amperometry for about 118 h in an acidic media, which shows that electrodes have a high degree of stability. In comparison to other previously reported work on catalyst-embedded electrodes, the Cu 2 CoSnS 4 embedded paper-working electrodes offer excellentpotential for HER activity across a wide pH range and are suitable for industrial application. • Cu 2 CoSnS 4 embedded paper working electrodes are developed for hydrogen generation. • The electrodes exhibit universal pH hydrogen evolution reaction. • Electrodes shows excellent stability upto 40hr for continuous hydrogen generation. • The electrode displays good stability at current density more than 200 mA/cm2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Evaluation of dark fermentative hydrogen production using paper mill effluent (PME) • Investigation of the impact of different HRTs on the biofilm reactor performance. • H 2 production rate was enhanced to 6.21 L H 2 d−1 L−1 by decreasing HRT to 2 h. • Max. yield of H 2 was 0.96 mmol H 2 g−1 COD at 8 h HRT. • Production of VFAs as valuable by-products as well as COD removal. This study assessed the feasibility of continuous hydrogen production in an anaerobic packed bed biofilm reactor (APBR) using paper mill effluent (PME) without any pretreatment or modification. To form a microbial biofilm on supports, the reactor was seeded with a thermal pretreated anaerobic sludge. After the start-up stage, under mesophilic conditions and pH control, the system performance in the case of hydrogen production as biofuel and VFAs as valuable by-products as well as COD removal was investigated at different hydraulic retention times (HRTs) (24, 16, 12, 8, 4, 2 and 1.2 h). The highest hydrogen concentration in the produced gas was 41.5 % obtained at HRT 4 h. The highest hydrogen production rate and yield were 6.21 L H 2 d−1 L−1 at HRT 2 h and 0.96 mmol H 2 g−1 COD at HRT 8 h, respectively. With decreasing the HRT from 24 to 1.2 h, the OLR was increased from 27.35 to 547 g COD L−1 d−1 that positively affect the hydrogen production rate for all HRTs except for the shortest HRT. Furthermore, COD removal efficiency was reduced from 25.2 to 6 %. Low value of COD removal efficiency is because of conversion of organic inlet to valuable metabolites such as VFAs in the effluent. [ABSTRACT FROM AUTHOR]

Biohythane, the promising gaseous biofuel, can be produced by the recirculated two-phase anaerobic digestion (R-TPAD). The effect of hydraulic retention time (HRT) as 30, 20 and 10 days on biohythane production via R-TPAD (recirculation ratio = 0.4) was investigated with co-digestion of food waste and paper waste. The results showed that HRTs of 30 and 20 days maintained stable performance for R-TPAD but HRT of 10 days led to the final decrease in biogas production. The failure in the end was attributed to the wash-out of microbes. The removal efficiencies for COD and carbohydrates were decreased by short HRTs while for VS it remained relatively stable at about 75.7 ± 4.0%. All through the operation, acidogenic phase and methanogenic phase were separated stably and butyrate pathway was the dominant pathway for hydrogen fermentation in the first stage. The microbial community in the first stage reached the highest diversity when total HRT was 20 days, where the hydrogen production rate was the highest. The genera Lactobacillus and Caproiciproducens kept dominating the dark fermentation in the acidogenic phase, and Ruminococcus and Methanosarcina were decreasing in the methanogenic phase. The biohythane yields were 411 mL/g-VS fed , 332 mL/g-VS fed and 253 mL/g-VS fed , respectively, where the H 2 contents were 18.4%, 14.7% and 8.8%, respectively. [Display omitted] • The R-TPAD system (R = 0.4) was operated for biohythane production. • R-TPAD operated under HRTs of 30 and 20 maintained stable performance. • Organic removals and biohythane yields were lowered by short HRTs. • Different microbial communities were identified by co-occurrence network. • Biohythane yields affected by different parameters were discussed. [ABSTRACT FROM AUTHOR]

In this work, a paper-based hydrogen fuel cell is developed without the need for hydrogen storage. Instead, an embedded aluminum foil inside the paper is utilized for in-situ hydrogen generation. The electrodes and current collectors are also deposited on the paper, leading to a lightweight, compact and flexible hydrogen fuel cell with an OCV reaching 0.93 V and a peak power density of 4 mW cm−2. Benefited from the impeded hydroxyl ion diffusion, the hydrogen generation rate is well controlled, leading to a high faradaic efficiency of 72%. In addition, the cell can be operated under different bending angles with negligible power loss. Furthermore, it can be conveniently stacked in the same piece of paper for higher voltage and power outputs. Such a novel fuel cell design is especially suitable for powering various flexible devices with small rated power. • A paper-based hydrogen fuel cell is developed with an OCV of 0.93 V. • The peak power density is 4 mW cm−2 and the maximum current density is 8 mA cm−2. • Faradaic efficiency and energy efficiency are as high as 72% and 18%, respectively. • 75–87.5% of the cell performance remains when bended by angles from 45° to 135°. • A 4-cell stack is developed with an OCV of 3.8 V and a stacking efficiency of 90.6%. [ABSTRACT FROM AUTHOR]

Cost-effective, simple and flexible hydrogen gas sensors operating at room temperature were demonstrated based on DC magnetron sputtered palladium thin films. The main idea is to use commercial microfiber filtration paper as a cheap, fibrous and flexible substrate for palladium. With this objective, Pd thin films with 21, 38 and 54 nm thicknesses were deposited and characterized by grazing incident X-ray diffraction (GIXRD) and scanning electron microscope (SEM). The gas sensing behavior was tested by hydrogen gas in the concentration rang of 0.5–10%. GIXRD showed a PdX/Pd phase and SEM revealed existing of many structural nanocracks. An activation process was needed where sensors were heated up to 110 °C in the presence of 10% H 2. Then a desirable hydrogen sensitivity with good stability based on hydrogen induced lattice expansion (HILE) effect in which conductance increases was observed. However, for low Pd thicknesses (21 and 38 nm) and at below 4% H 2 , an inverse effect was observed in which the conductance decreased instead of increasing. For all samples the response time is incremental in the range of 0.5–4% and declining for 4–10%. Moreover, the deposited Pd sensors operate well when they are bent inward or outward. The governed physical mechanism was expressed and discussed. • Pd thin films were deposited on microfiber filtration paper by DC sputtering method. • Their hydrogen sensing properties were examined for different Pd thicknesses. • Sensing mechanisms including invers and direct current responses were observed. • The stability of sensing response of fabricated sensors was examined. • The response to bending in presence and absence of gas was investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Paper mill sludge is a carbohydrate rich substrate for bioenergy production. • Floc dissociation can enhance bacterial disintegration of biomass. • Floc removal was optimized at 0.05 g/g SS of calcium peroxide at 70 °C. • Thermal calcium peroxide-bacterial pretreatment exhibits 18.6% solubilization. • Increase in solubilization aids in efficient generation of hydrogen of 94.1 mL/gCOD. This study envisioned attaining the percipience of effective biohydrogen production from paper mill waste-activated sludge through low-temperature calcium peroxide-mediated bacterial pretreatment (TCP-BP). Floc dissociation with limited cell destruction was attained at a calcium peroxide dosage of 0.05 g/g suspended solids (SS) at 70 °C temperature. This TCP-BP method improves bacterial fragmentation, and very high SS solubilization was achieved at 42 h, with the solubilization and solid reduction of 18.6% and 14.1%, respectively. BP-only pretreatment shows lower solubilization efficiency of 9.4% than TCP-BP pretreatment due to the presence of flocs, which inhibit the enzymatic action during bacterial fragmentation. A biohydrogen test shows a high biohydrogen potential of 94.1 mL H 2 /gCOD for the TCP-BP sample, which is higher than that of the BP-only and control samples. According to the findings, low-temperature calcium peroxide-mediated bacterial fragmentation is validated to be an efficient process for sludge degradation and biohydrogen production. [ABSTRACT FROM AUTHOR]

“Mass transfer in catalyst supports”and “reactive sites”are two critical factors for supported thin film catalysts. Based on such considerations, paper composed of cellulose fibers (CFs) is chosen as a competent nano-catalyst carrier because its broad porous structure is conducive to mass transfer. Then a facile aquatic synergistic synthesis is developed to decorate polypyrrole (PPy) encapsulated palladium nano-composites onto the CF paper structures. The pyrrole monomers (Py) reduce Pd 2+ to Pd nanoparticles in aqueous solution, and meanwhile the Pd 2+ initiates the polymerization of Py to PPy. In the as-prepared composite paper catalysts, the broad pores constructed by the microfibers facilitate the reactant diffusion and the Pd/PPy nanoparticles supported on the fibers provide more reactive sites for catalysis. As a result, the catalytic activity for hydrolysis of ammonia borane is improved. The H 2 turnover frequency is 21.1 mol H 2 mol Pd −1 min −1 , surpassed most other Pd based film catalysts. Importantly, excellent stability and reproducibility are also realized by the immobilization of Pd NPs by PPy layers onto fibers. [ABSTRACT FROM AUTHOR]

[Display omitted] • A paper-based photoanode is developed for photoelectrochemical water splitting. • MoSe 2 nanosheet anchored CdS-ZnO array functional paper is prepared. • Tandem Z-scheme configuration with double IEFs and photothermal effect are integrated. • The flexible photoanode achieves admirable solar water splitting performance. Rational design of photoelectrode architectures is deemed as an effective solution to enhance efficiency of photoelectrochemical water splitting for conquering increasingly prominent environmental problems. Herein, a programmable flexible photoanode with built-in tandem Z-scheme configuration fabricated by in-situ growth of MoSe 2 -CdS-ZnO array with ultrathin nanosheet-interlaced-nanorod structure on the Au paper electrode, is firstly reported. By taking advantages of the interwoven nanonetwork structure, high conductivity as well as larger porosity of the as-fabricated Au paper electrode, a stable light-harvesting paper chip with fast transfer/separate mediators of the charge/carriers is thus integrated. By virtue of double internal electric fields (IEFs) and photothermal effect, the developed MoSe 2 -CdS-ZnO photoanode exhibits incident-photon-to-current efficiency of 52 % under 460 nm of light irradiation, and the current density reaches 2.4 mA cm−2 at 0.3 V versus normal hydrogen electrode, which is comparable with respect to current state-of-the-art "type-II-scheme", "surface-scheme", and cocatalyst-free photocatalysts (0.03–2.4 mA cm−2). Consequently, the paper-based photoanode achieves admirable photoelectrocatalytic hydrogen generation property (39.7 μmol cm−2 h-1). The synergistic effect of tailorable tandem Z-scheme configuration with double IEFs and delineating of 3D cross-linked network structure of the proposed photoanode in this work may open an avenue for constructing high-performance photoelectrochemical water splitting devices. [ABSTRACT FROM AUTHOR]

Nowadays, hydrogen is gaining attention as one of the green energy alternatives within transition to a zero-emission economy. Increasing demand for hydrogen and its production has prompted the development of low-carbon strategies and technologies for hydrogen generation from hydrocarbons. This paper provides a thorough analysis of traditional and innovative methods for hydrogen production from fossil feedstock, reviewing the critical aspects and recent advancements in the field. The paper emphasizes the potential of in situ hydrogen generation as the most promising method, taking into account CO2 emission concerns. Additionally, this study explores the use of software packages for modeling hydrogen production, outlining their advantages and disadvantages and proposing the most favorable software for in situ hydrogen generation from hydrocarbons. Subsequent analysis sheds light on the effectiveness, economic viability, environmental impact, and future perspectives of various hydrogen production technologies. • Overview of hydrogen production technologies: conventional and innovative methods. • Key issues and best practices of the latest experimental and numerical studies. • Comparative analysis of various hydrogen production technologies and approaches. • Subsurface hydrogen generation has a great development potential. • There are methods for clean hydrogen production from hydrocarbon feedstock. [ABSTRACT FROM AUTHOR]

The design and development of efficient nitride photocatalysts have attracted much attention. Herein, two-dimensional mesoporous Ta 3 N 5 is successfully synthesized through a simple sol-gel process with filter paper as a biological template and a combination of vacuum nitriding reactions. The prepared Ta 3 N 5 shows a wide light response range up to the near infrared (NIR) region due to the nitrogen vacancies generated from substitution of N3− for O2− ions during vacuum nitridation. Significantly, such a narrow bandgap (∼1.99 eV) still satisfies the redox potential of water splitting in thermodynamics. The experimental results show that the Ta 3 N 5 photocatalyst exhibits an enhanced hydrogen production rate of 34.6 μmol h−1 g−1, which is 3.9 and 2.1 times higher than that of Ta 2 O 5 and partial nitridation of Ta 2 O 5 (N–Ta 2 O 5), respectively. This enhanced photocatalytic performance could be attributed to the high specific surface area to provide reactive active sites, substitution of N3− for O2− ions to optimize the band structure, and special two-dimensional mesoporous structure to shorten the charge transfer distance. This work provides a new perspective for the preparation of two-dimensional nitride materials by a biological template method combining vacuum nitriding with enhanced photocatalytic performance. Two-dimensional mesoporous Ta 3 N 5 is synthesized by a simple sol-gel process with filter paper as a biological template and vacuum nitriding reaction, leading to an efficient photocatalytic performance. [Display omitted] • Two-dimensional mesoporous Ta 3 N 5 was prepared by a biological template. • The prepared Ta 3 N 5 shows a wide light response range up to the near infrared region. • The special two-dimensional structure shortens the charge transfer distance. • The Ta 3 N 5 photocatalyst shows a superior hydrogen production performance. [ABSTRACT FROM AUTHOR]

Offshore wind-hydrogen systems operate in harsh marine environments for extended periods, posing risks of low accessibility and high failure rates. This paper proposes a data-driven fault detection framework for offshore wind-hydrogen systems, aiming to promptly detect potential faults based on the system's physical parameters. The research establishes a comprehensive model based on the operating principles of offshore wind-hydrogen systems. The study uses fault injection techniques to simulate common partial faults in offshore wind-hydrogen systems and collects relevant physical parameters (such as wind turbine power generation, energy storage battery charging/discharging current, and electrolyzer hydrogen production rate). A fault detection model was constructed using a combination of Convolutional Neural Networks (CNN) and Bidirectional Long Short-Term Memory (BiLSTM) to enable precise detection of potential faults in the system. The established model provides theoretical support for designing, optimizing, and operating offshore wind-hydrogen systems, reducing reliance on actual experiments and lowering project risks and costs. Introducing artificial faults can evaluate the system's performance in different fault scenarios. This paper proposes a CNN-BiLSTM fault detection method that achieves automatic feature extraction and high-precision classification of time-series fault data, confirming the practicality and feasibility of offshore wind-hydrogen systems. This investigation realizes the integration of the offshore wind-hydrogen system model and deep learning, as well as a fully automated learning process from data to fault detection. By calculating and comparing results, it is verified that the framework has a high accuracy of 96.9%. This innovative research offers new methods and perspectives for enhancing the reliability and efficiency of fault detection in offshore wind-hydrogen systems. • A comprehensive multi-system simulation model for offshore wind-hydrogen systems is established. • Fault injection is employed to acquire data samples for offshore wind-hydrogen systems. • Utilizing the CNN-BiLSTM method, a high-accuracy deep learning fault detection model is crafted. • A simulation model-based data-driven deep learning framework for fault detection is devised in this study. [ABSTRACT FROM AUTHOR]

Hydrogen is a relatively new source of sustainable energy resources; presently, its usage ranges from direct energy generation in mixed-cycle thermal power plants to its usage in the internal combustion engine. If the generation of hydrogen is coupled with renewable energy resources, the use of hydrocarbons can be substantially reduced in both energy generation and transportation. In this paper, we conducted a national-level assessment to identify the hydrogen generation capacity of Pakistan. The methodology used in this study is a combination of spatial multi-criteria analysis and density-based clustering in a geographical information systems environment. Based on the analysis, the national clusters capable of producing green hydrogen were identified. The results shows that the hydrogen generation capacity for Pakistan is approximately 7 million tons per year using solar photovoltaic energy. The Surab-Gwadar alignment, N-25 national highway, and Quetta-to-D-I-Khan alignment offer potential hydrogen generation sites with water resources. Most of the identified sites for the production of hydrogen in the country were found to be near the national electricity transmission networks. The Best-Worst Method was further employed to provide policymakers with a road map for prioritizing the development of these capacities based on their proximity to the national networks, their terrain suitability, and their generation capacities. • This paper assesses the suitable sites for solar-based green hydrogen production in Pakistan. • The methodology used involves a combination of spatial multicriteria analysis, clustering, and the best-worst method. • Pakistan's theoretical annual hydrogen generation capacity is around 7 million tons annually. • The Surab-Gwadar alignment presents promising hydrogen generation opportunities. [ABSTRACT FROM AUTHOR]

Microbial electrolysis cells (MECs) are emerging sustainable power generation technologies that can be used for biohydrogen production and wastewater treatment. The prospect for hydrogen gas as a vehicle fuel suitable for the environment is enormous. MEC serves as a reactor for producing biohydrogen by mixing MFC with electrolysis. MECs are the most sustainable, clean, and effective ways to produce biohydrogen. Effective aspects impacting H 2 production, including microbial culture, electrodes, membrane, and substrate, have been explored for greater comprehension of creating MEC technology-based hydrogen generation. The present issues with effective scale-up include the costly production expenses of microbial electrolysis cells, their significant internal resistance, methanogenesis, and membrane/cathode biofouling. This review examines the various operational parameters in optimization studies that influence overall hydrogen generation. This paper also presents strategies to overcome the constraints listed above by creating effective architecture, including several reactor designs, biological, and physical properties, and the use of various operational conditions for improved hydrogen production. This study summarizes recent developments and several other operating factors (organic loading, ionic strength, hydraulic retention time, applied voltage, etc.) that affect hydrogen production in an MEC system. The paper outlines the present technical difficulties and offers practical future ideas for addressing the constraints. [Display omitted] • MEC has great efficiency in hydrogen recovery and concurrent waste conversion. • Microbial culture, electrodes, membrane, and substrate affect H 2 production in MEC. • Scale-up constraints: high costs, internal resistance, methanogenesis, and biofouling. • Modifying strain, nanoparticles, and reactor design can help in overcoming this. [ABSTRACT FROM AUTHOR]

It reviews the papers reporting on the use of rhodium nanocatalysts in hydrogen generation from the hydrolysis of ammonia borane in the following groups: (i) water soluble rhodium complexes, (ii) colloidal nanoparticles of rhodium, (iii) rhodium(0) nanoparticles supported on carbonaceous materials such as activated carbon, graphene, carbon nanotubes, (iv) the use of oxide supports for rhodium(0) nanoparticles, (v) the use of magnetic powders as support for rhodium(0) nanoparticles to make them magnetically recoverable. In each group, the reported results are evaluated by considering the increase in the catalytic activity (specifically measured in turnover frequency), the stability and durability, the lifetime (that is, how long the nanocatalyst can be used in releasing hydrogen gas from the hydrolysis of ammonia borane at appreciable rate), reusability (that is, how many times the catalyst can be isolated and reused for the same hydrolysis reaction generating hydrogen at acceptable rate). Overall, the work reported in each of the papers is evaluated in terms of contribution to the catalytic efficiency of rhodium nanocatalysts in hydrogen generation from the hydrolysis of ammonia borane at room temperature. At the end, conclusions and suggestions are given how to increase the overall catalytic efficacy of the precious rhodium nanocatalysts in hydrolytic dehydrogenation of ammonia borane. [Display omitted] • Using colloidal nanoparticles is an efficient way of increasing catalytic activity of rhodium catalysts. • Supporting the rhodium nanoparticles on materials with large surface area increases their stability. • Selecting a suitable oxide support can increase the catalytic efficiency of rhodium nanocatalysts. • Reusability of rhodium nanoparticles can be increased by using magnetic support. [ABSTRACT FROM AUTHOR]

The number of Fuel Cell Electric Vehicles (FCEVs) in circulation has undergone a significant increase in recent years. This trend is foreseen to be stronger in the near future. In correlation with the FCEVs market increase, the hydrogen delivery infrastructure must be developed. With this aim, many countries have announced ambitious projects. For example, Spain has the objective of increasing the number of Hydrogen Refuelling Stations (HRS) with public access from three units in operation currently to about 150 by 2030. HRSs are complex systems with high variability in terms of layout design, size of components, operational strategy, hydrogen generation method or hydrogen generation location. This paper is focused on on-site HRS with electrolysis-based hydrogen production, which provides interesting advantages when renewable energy is utilized compared to off-site hydrogen production despite their complexity. To optimize HRS design and operation, a simulation model must be implemented. This paper describes a generic on-site HRS with electrolysis-based hydrogen production, a cascaded multi-tank storage system with multiple compressors, renewable energy sources, and multiple types of dispensing formats. A modelling approach of the layout is presented and tested with real-based parameters of an HRS currently under development, which is capable of producing 11.34 kg/h of green H 2 with irradiation at 1000 W/m2. For the operation, an operational strategy is proposed. The modelled system is tested through several simulations. A sensitivity analysis of the effects of hydrogen demand and day-ahead hydrogen production objective on emissions, demand satisfaction and variable costs is performed. Simulation results show how the operational strategy has achieved service up to 310 FCEVs refuelling events of heavy duty and light duty FCEVs, bringing the total H 2 sold up to almost 7200 H2kg in one month of winter. Additionally, considering variable costs of the energy from the utility grid, the model shows a profit in the range of 21–50 k€ for a daily demand of 60 H2kg/day and 100 H2kg/day, respectively. In terms of emissions, a year simulation with 60 H2kg/day of demand shows specific emissions in the production of H 2 in Spain of 6.26 kgCO2eq/H2kg, which represents a greenhouse gas emission intensity of 52.26 gCO2eq/H2MJ. • Modelling approach of hydrogen refuelling station with on-site hydrogen production. • Operational strategy with day-ahead scheduled grid-connected hydrogen production. • Finite-state machine online control of a multi-tank and multi-compressor plant. • Sensitivity analysis of hydrogen demand magnitude and frequency. • A trade-off between demand satisfaction, profits and emissions. [ABSTRACT FROM AUTHOR]

In proton exchange membrane water electrolysis system, higher hydrogen production rate, as well as medical-grade ozone generation is obtained if the applied voltage is increased from 2.0 V to 3.5 V. However, this also leads to harsh conditions encountered by both anode and anode support of membrane electrode assembly. For example, Ti plate as anode support, needs coating to prevent corrosion and to stabilize operation. In this study, commercial Ti plates are polished with sand papers of different degree of roughness before electrocoating. The characteristics of the coated Ti anode support are determined by field-emission scanning electron microscope (FE-SEM), energy dispersive spectrometer (EDS), electrochemical impedance spectroscopy (EIS), and electrolyzer test. In conclusion, the performance of coated Ti anode support improved with polish, reach a maximum and then decrease with highest degree roughness. • Polishing metallic anode plate surface reduces the ICR. • Optimal roughness of metallic anode plate is beneficial for anti-corrosion materials attachment. • Anti-corrosion materials attachment lead to stable PEMWE performance. • Ti plate polished with P1200 sand paper gives optimum performance in PEMWE. [ABSTRACT FROM AUTHOR]

Reforming ammonia to hydrogen using engine exhaust waste heat is a promising technology to improve the combustion performance and reduce the exhaust emissions of ammonia-fueled engines. However, there are still a research gap between the laboratory-level catalytic reforming tests and the practical application in engine systems. In particular, there are urgent needs to further understanding the ammonia reforming characteristics and developing the simulaiton models for the engine system optimization. In this paper, we conducted the experiments of catalytic reforming NH 3 to H 2 to study the effects of the reaction temperature, gas hour space velocity (GHSV) and pressure on the thermo-catalytic decomposition characteristicsxin. The results indicate that both the ammonia catalytic conversion and reforming efficiency exhibit an increasing trend with the rise in reaction temperature, while these two parameters demonstrate a decreasing trend with the increase in GHSV and pressure. The rate of hydrogen production is directly proportional to temperature, GHSV, and reaction pressure. Conversely, the energy required per unit of hydrogen production decreases with temperature but increases with GHSV and reaction pressure. The energy flow analysis shows that increasing the reforming temperature increases the reforming losses, but the total calorific value of the reformate increases, which is expected to improve the overall efficiency of ammonia fueled engines and reduce the unburned ammonia emissions. Simulation results show that, the improved Temkin-Pyzhev global rate model can significantly improve the accuracy of the ammonia catalytic decomposition process prediction. [Display omitted] • A novel energy flow analysis method for thermo-catalytic reforming is presented. • A precise predictive model for thermo-catalytic characteristics is established. • The thermo-catalytic system has a system efficiency of up to 94%. • The thermo-catalytic system has a reforming efficiency of up to 112%. [ABSTRACT FROM AUTHOR]

The demand for susceptible and selective hydrogen gas sensors is growing in fuel cells, chemical production, and automotive industries. Detecting H 2 gas at the ppm or ppb level is crucial due to its colourless, odourless, tasteless nature, as well as its flammability and explosiveness. Transition metal dichalcogenides (TMDs) and metal oxide (MO) semiconductors-based hybrid structures have garnered attention in recent years as promising candidates for gas sensing applications owing to their unique properties, including a high surface area, tunable bandgap, and strong gas adsorption. This paper aims to offer insights into the potential of TMD-MO hybrid structures as the next generation of hydrogen gas sensing platforms, contributing to developing highly sensitive and selective gas sensors for diverse industrial applications. TMD-MO hybrid structures are vital for detecting hydrogen gas with high sensitivity and selectivity, which are essential for safe and efficient hydrogen-based systems. Furthermore, these hybrid structures hold significant potential for further customization and enhancement to suit specific applications. Overall, TMD-MO hybrid structures offer a promising avenue for developing next-generation hydrogen gas sensors useable in various industrial applications and promoting a safe and sustainable hydrogen economy. [ABSTRACT FROM AUTHOR]

A method concerning re-use of the main greenhouse gases: CO 2 and CH 4 at the same time producing value-added chemicals (H 2 + CO) is presented in this paper. The method involves the methane dry reforming using an atmospheric pressure operated 915 MHz microwave plasma source with a swirl gas flow. The effect of the CO 2 to CH 4 flow rates ratio, the total gas flow rate and the absorbed microwave power on the volume concentration of the gaseous plasma component in the outlet gas (%), CO 2 and CH 4 conversion rate (%), hydrogen production rate (g h−1) and energy yield of hydrogen production (g kWh−1) was investigated experimentally. The recorded results of the CO 2 and CH 4 conversion rate were about 82% and 88%, respectively. The best results in terms of the hydrogen production rate and energy yield of hydrogen production were equal to 156 g h−1 and 24 g kWh−1, respectively. [Display omitted] • Dry methane reforming using 915 MHz microwave plasma of high gas flows was studied. • Recorded CO 2 and CH 4 conversion rates were up to 82% and 88%, respectively. • Achieved hydrogen production and energy yield of 156 g h−1 and 24 g/kWh, respectively. • CO 2 and CH 4 conversions are comparable with the results obtained at 2.45 GHz plasma. • Results promising for industrial DRM of high gas flow and 915 MHz microwave power. [ABSTRACT FROM AUTHOR]

This paper introduces a confinement approach to enhance solid-state hydrogen storage by designing a nano-tubular and nano-fibrous structured boron-based storage medium. We detail the preparation of the confinement matrix, emphasizing its nanotubular and microfibrous structures provided by activated halloysite and sepiolite clays to achieve suitable confinement for ammonia borane (NH 3 BH 3 , AB). The thermolysis characteristics are thoroughly investigated in a lab-scale hydrogen reactor, elucidating the activation effects (thermal, acid, and both thermal-acid) on confinement and hydrogen generation performance. The resulting composite exhibits improved thermal stability and controlled hydrogen desorption characteristics, offering great promise for safe and efficient hydrogen storage applications. This research underscores the potential of tailored nanomaterials in advancing hydrogen storage technologies, with significant implications for clean energy solutions and the sustainable transportation sector. AB confined in acid-activated nano-tubular clay has shown improved hydrogen generation features at 120 °C, resulting in the highest improvement in H 2 equivalent per AB mole (98 %) and the initial hydrogen generation rate (233 %) while minimizing induction time up to 90 %. [Display omitted] • Tubular and fiber structured clays were used as ammonia borane scaffolds medium. • Halloysite and sepiolite clays were activated by thermal, acidic and combined method. • NH 3 BH 3 based nanocarriers were prepared via modified infiltration-confinement method. • Hydrogen production performance of composites were tested at 120 °C. • Acid activated composites showed the highest performance. [ABSTRACT FROM AUTHOR]

The necessity of employing renewable energy sources within microgrid-based Power-to-X (P2X) systems has been emphasized by the imperatives of reducing global warming and fossil fuel consumption. Due to their numerous advantages, solar and wind energy have acquired prominence in contemporary power systems. However, their intermittent nature presents challenges. To overcome these challenges, energy storage devices are utilized. Batteries, however, are plagued by issues such as high maintenance needs, self-discharge, and diminishing storage capacity with age. Consequently, investigating alternatives such as hydrogen storage has become a financially viable option, especially for high-power applications. However, the intrinsically slow dynamics of hydrogen production from electricity contrast with the rapid responses of contemporary power electronic devices. This paper presents a versatile technique for optimizing hydrogen production in the presence of stochastic fluctuations in solar irradiance and wind speed. The proposed method combines a modified version of the Symbiotic Differential Whale Optimization Algorithm (m-SDWOA) with power converters to maximize production from renewable sources and electrolyzers. Using extensive simulations to demonstrate the efficacy of the proposed method by comparing its performance to that of the Whale Optimization Algorithm (WOA) and Particle Swarm Optimization (PSO). The results demonstrate the superior performance of the m-SDWOA-integrated method and pave the way for improved hydrogen generation in microgrid-based P2X systems. • Innovative control framework coordinates WT, PV, BESS, and HESS. • Maximizes hydrogen production while maintaining power quality. • Efficient controllers stabilize DC-bus voltage amidst WT/PV variability. • Ensures consistent, reliable power supply in microgrid. • Efficient energy management via m-SDWOA for resource optimization. [ABSTRACT FROM AUTHOR]

The current paper deals with the development and analysis of an innovative multigeneration plant, which is powered by geothermal energy, and integrated with the transcritical Rankine cycle ( t C O 2 − R C), proton exchange membrane (PEM) electrolyzer, multi-effect desalination unit (MED), and ejector cooling system (ECS). The main objective of this research paper is to produce power, hydrogen, freshwater, and cooling in an environmentally benign way, by integrating the different subsystems. A comprehensive parametric analysis that is thermodynamic and economic and exergo-environmental impact assessment are addressed. For these parametric analyses, the variation of some important parameters that affect the system performance is examined and illustrated. According to the modeling findings, the net power and hydrogen production capacity of the modeled combined power plant is 982.4 kW and 0.0024 kgs−1, respectively. The cycle's overall energy efficiency is computed to be 40.04%, although its exergetic efficiency is 36.31%. When the irreversibility among the plant components is compared, the highest irreversibility occurred in the PEM water heater with 1508 kW, followed by heat exchangers 1 and 2. Given the economic results, the modeled plant's cost rate is calculated to be 200.2 $/hr. In the end, it can be recommended that this modeled plant is suitable that is from the point of perspective of the performance, economy, and exergo-environmental relations. • A novel multigeneration plant motivated by geothermal energy is proposed. • Modeling and analysis of a multigeneration plant for power, hydrogen, cooling, and freshwater production. • Energy, exergy, economic, and exergo-environmental index analyses are conducted. • Investigating the green and sustainable hydrogen generation method with PEM electrolyzer. • The overall energy and exergy efficiencies are 40.04% and 36.31%, respectively. [ABSTRACT FROM AUTHOR]

N-rich precursors govern the thermal polymerization formation of graphitic carbon nitride (g-C 3 N 4) based catalysts towards enhanced photocatalytic performance. In this paper, Cu components were introduced in superior thin g-C 3 N 4 nanosheets using the thermal polymerization copper acetate and bulk g-C 3 N 4 created by different precursors including melamine, dicyandiamide, and thiourea, such as melamine-g-C 3 N 4 (MCN), dicyandiamide-g-C 3 N 4 (DCN), and thiourea-g-C 3 N 4 (TCN). The performance of Cu-g-C 3 N 4 nanosheets depended strongly on the precursors of bulk g-C 3 N 4 samples. The well-developed Cu nanoparticles with clear lattice fringes were observed in the sample prepared using MCN (sample Cu-MCN) while the crystallinity of Cu nanoparticles became worse in the sample prepared using DCN (sample Cu-DCN). Interestingly, Cu clusters were homogeneously distributed in superior thin g-C 3 N 4 nanosheets in the case of using TCN (sample Cu-TCN) because of S components in thiourea affected the thermal polymerization. The photocatalytic activity of Cu-TCN was drastically improved compared with other Cu-g-C 3 N 4 samples. The photocatalytic hydrogen production rate of Cu-TCN with 1% of Cu components was 4035.6 μmol g-1 h-1. Cycle stability test indicated that sample Cu-TCN revealed high stability, in which the H 2 generation rate was retained 95% of their initial value after 5 cycles. These results supply efficient approaches for the study and application of g-C 3 N 4 based photocatalysts. • Cu components introduced in g-C 3 N 4 nanosheets using bulk g-C 3 N 4 created by different precursors. • Precursors (melamine, dicyandiamide, and thiourea) affect the activity of Cu-g-C 3 N 4 nanosheets. • Cu distribution in g-C 3 N 4 nanosheets depended on the thermal polymerization of precursors. • Cu clusters distributed in g-C 3 N 4 nanosheets created using thiourea revealed the best performance. [ABSTRACT FROM AUTHOR]

Present paper aims to investigate effects of nanoparticle addition to thermal oil of parabolic trough collectors which are integrated to Kalina cycle for electricity generation to run an alkaline electrolyzer for hydrogen production. Thermodynamic models for Kalina cycle, thermal model for parabolic collectors and electrochemical models for water electrolyzer are developed for overall plant modeling. Three types of nanoparticles including: copper oxide, alumina and titanium oxide are considered and overall plant performance is investigated using these nanoparticles and is compared with basefluid. The nanofluid thermophysical properties are evaluated as a function of nanoparticles' properties, volume fraction and the base fluid properties. The effects of key variables such as nanoparticle volume fraction, collector inlet temperature, evaporation pressure and ammonia concentration of Kalina system were evaluated on hydrogen production as well as exergetic efficiencies. Results revealed greater positive influence for CuO compared to TiO 2 and Al 2 O 3 on performance improvement for both hydrogen generation and its exergetic efficiency. Also, compared to basefluid (without nanoparticles) case, it was found that CuO particles result in a solar-to-H 2 exergy efficiency improvement by 4.7%. Using this nanofluid with a volume fraction of 5%, the H 2 production rate enhances from 0.633 kg / h to 0.664 kg / h , indicating 4.9 % improvement. • An alkaline electrolyzer-based hydrogen production plant powered by PTC is modeled. • Three types of nanoparticles are employed for hydrogen production enhancement. • Copper oxide nanoparticles are found to be better than titanium oxide and alumina. • Nanoparticles are applied to enhance the PTC thermal performance. • Hydrogen production rate can be enhanced by 4.9 % using CuO nanoparticles. [ABSTRACT FROM AUTHOR]

Proton exchange membrane (PEM) electrolyzers are promising devices for hydrogen production from water splitting, but their performance and stability are still limited by various factors. This paper studies the effects of different structures on the performance of PEM electrolyzers, focusing on the working temperature, water conductivity, and the structure of bipolar plate. The results show that higher temperature and lower water conductivity enhance the electrolyzer performance, by increasing the catalyst activity and the proton transport. Moreover, a novel structure using a platinum-coated titanium mesh-based bipolar plate is proposed and tested. This structure improves the performance of the electrolyzer, by optimizing the mass transport, pressure drop, and water management in the electrolyzer. A 23-cell electrolyzer with this structure is developed and demonstrated. The electrolyzer achieves a high performance and stability, with a cell voltage of 1.742 V, a voltage efficiency of 85.0%, and a hydrogen production rate of 1.14 Nm3/h at 0.99 A/cm2. The observed cell voltage for the PEM electrolyzer is consistent with the documented range, typically spanning from 1.55 to 1.90 V at a current density of 0.99 A/cm2. This suggests that our bipolar plate design simplifies PEM electrolyzer manufacture while maintaining comparable performance to existing electrolyzers. [Display omitted] • Performance of PEM electrolyzers affected by different structures. • Higher temperature and lower water conductivity enhance performance. • Platinum-coated titanium mesh as flow field plate improves performance. • 23-cell electrolyzer with novel structure achieves high performance and stability. [ABSTRACT FROM AUTHOR]

A dedicated grid-tied offshore hybrid energy system for hydrogen production is a promising solution to unlock the full benefit of offshore wind and solar energy and realize decarbonization and sustainable energy security targets in electricity and other sectors. Current knowledge of these offshore hybrid systems is limited, particularly in the integration, component control, and allocation aspects. Therefore, a grid-integrated analytical model with a power dispatch allocation strategy between the grid and electrolyzer for the co-production of hydrogen from the offshore hybrid energy system is developed in this paper. While producing hydrogen, the proposed offshore hybrid energy system supplies a percentage of its capacity to the onshore grid facility, and the amount of the electricity is quantified based on the electricity market price and available total offshore generation. The detailed controls of each component are discussed. A case study considers a hypothetical hybrid offshore energy system of 10 MW situated in a potential offshore off the NSW of Australia based on realistic metrological data. A grid-scale proton-exchange membrane electrolyzer stack is used and a model predictive power controller is implemented on the distributed hydrogen generation scheme. The model is helpful for the assessment or optimization of both the economics and feasibility of the dedicated offshore hybrid energy farm for hydrogen production systems. • Modeling of a grid-integrated analytical model of an OHES for hydrogen co-production. • Development of a power dispatch allocation strategy for the proposed OHES. • Development of detailed controls of each component used in the proposed OHES. • Demonstrations of a case study considering 10 MW OHES situated in offshore off the NSW of Australia. [ABSTRACT FROM AUTHOR]

This comprehensive review delves into the utilization of ultrasound for hydrogen generation, emphasizing the key mechanisms and techniques involved. One of the focal points of the study is the exploration of the generation and detection of cavitation bubbles, which are induced by ultrasound waves. An in-depth overview of various experimental setups that employ ultrasound technology for hydrogen production is also provided. A comparative analysis of these setups reveals differences in crucial parameters such as acoustic intensity, liquid temperature, and frequency. These are the key parameters identified as significant determinants affecting the hydrogen yield and efficiency. This review paper also highlights the potential applications of sonohydrogen as a viable energy resource. While challenges such as the high costs of ultrasound equipment and the need for efficient catalysts exist, the inherent benefits make sonohydrogen a compelling subject for future research and development. The study shows that there is no one-size-fits-all approach, accentuating the importance of understanding these parameters for optimizing the process of hydrogen production. Although the technology is primarily in the experimental phase, existing research indicates that the sonohydrogen production holds considerable potential for large-scale applications. [Display omitted] • The study explores ultrasound's role in enhancing hydrogen production. • The article reviews various experimental setups and comparing them. • The manuscript identifies key parameters affecting sonohydrogen production. • The study discusses the potential dimensions of sonohydrogen options and future research directions. • It examines scaling sonohydrogen production challenges for industrial use. [ABSTRACT FROM AUTHOR]

In the wake of the devastating consequences of climate change, many countries are searching for alternative renewable energy. Hydrogen, the most abundant element on earth, is an alternative clean and non-toxic energy source. Palladium-based membranes and their alloys are categorized as inorganic metallic membranes with the highest selectivity and permeation rate for hydrogen production. Pd-based membranes have great potential for resolving environmental concerns and adverse side effects of greenhouse gases resulting from industrial processes. This paper analyses Pd-based membranes and their industrial applications while focusing on natural gas and methane as non-renewable feedstocks for hydrogen production. Steam reforming of natural gas and methane, partial oxidation reaction, auto thermal reforming, dry reforming, and gas to liquid process are among the processes that take place in a Pd-based membrane reactor and are discussed in this paper. Finally, all the ongoing research and development on both laboratory and industrial scales are reviewed. • The role of hydrogen as a sustainable and alternative energy vector is highlighted. • The use of Pd membrane and its alloys for methane and natural gas reforming processes is discussed. • The mainstream approaches to the production of hydrogen from methane and natural gas are reviewed. • The current industrial applications of palladium membrane reactors are presented. [ABSTRACT FROM AUTHOR]

Renewable hydrogen is considered as one of the key technologies that may be needed to fully decarbonise our economies, providing the high-temperature heat, fuels and feedstock that might not be possible to electrify. Several pilot projects are underway, and some assessments of the economics of green hydrogen have been published. However, most of them have assessed the costs of producing renewable hydrogen in large-scale, grid-connected units. Another option, pointed by many as a robust strategy in the early stages, is to produce hydrogen locally, in "hydrogen valleys", to serve industrial demand. In this paper, the economics of the different technical configurations and strategies that might be used for this decentralised, variable-demand option are analysed, accounting for the impact that a non-constant operation may cause on the operational efficiency of electrolysers, and for the potential benefits of local hydrogen storage. Our results show that when hydrogen demand is variable, production costs are higher compared to the constant demand case, due to the higher electrolyser size required. Electricity price optimization plus hydrogen storage can be a valuable option in some cases, although the cost benefit is negligible (about 1%) unless price volatility in the market increases with higher RES shares, or investment costs decrease significantly. Sourcing electricity exclusively from a dedicated renewable power plant can only become competitive if electricity market prices rise as observed recently or triggered by increasing CO 2 prices. • Different production strategies are compared to minimise H 2 production costs. • Faraday efficiency increases costs for variable electricity generation. • Electricity price optimization is best for H2 valleys, although compression costs may change this. • Direct H 2 production from renewable plants is not competitive with current prices. [ABSTRACT FROM AUTHOR]

Hydrogen is a great energy carrier that has the potential to reduce pollution and greenhouse emissions if produced by renewables and clean energy systems. However, moving from dependence on fossil fuels to renewables without emissions is a giant and challenging leap. Therefore, nuclear energy is a well-established technology that can help cut emissions and produce the electricity required for hydrogen production. Electrolysis is a promising technology that uses electricity to produce hydrogen from water. This paper investigates the integration of a large-scale PEM electrolysis with the APR1400 nuclear power plant to produce hydrogen. The two subsystems are, firstly, separately modeled using energy and exergy concepts to conduct parametric analysis on each individually. These subsystems are then integrated into one system to evaluate the system performance, hydrogen production rate, and overall system efficiency. The integrated system is examined with different operation conditions. It is found that the overall thermal-to-hydrogen energy and exergy efficiencies of the integrated system are 22.9% and 53.52%, respectively, and the hydrogen production rate is 7.544 kg/s; this makes 651 t per day and 19.5 kt per month. • An APR1400 plant is integrated with a PEM electrolyzer for hydrogen production. • The thermodynamic performance of the integrated system is parametrically analyzed. • The integrated system can produce hydrogen at an optimum exergy efficiency of 53.5%. • The integrated system produces 651 t of H2/day at an energy efficiency of about 23%. [ABSTRACT FROM AUTHOR]

This paper aims to study the feasibility of municipal sewage sludge utilization as an energy source in a polygeneration system. This system offers distinctive benefits such as contribution to the principled removal of sewage sludge, simultaneous utilization of raw and digested sludge in different parts of the system, and production of renewable hydrogen from bio-waste. 4E (energy, exergy, exergoeconomic, and environmental) analyses, are performed to understand the system performance comprehensively. Then, parametric studies are examined the impact of changing the values of main parameters on the system operation. Afterward, a multi-objective optimization based on a genetic algorithm is carried out to achieve optimal values, considering a trade-off between the exergy efficiency and the total cost rate. Meanwhile, this work harnesses the potential of artificial neural networks to expedite complex and time-consuming optimization processes. According to the results, the gasifier exhibits the highest rate of exergy destruction, and the primary cost of consumption is attributed to its heat supply. The multi-objective optimization findings show that the optimum point has an exergy efficiency of 38.26 % and a total cost rate of 58.17 M$/year. The hydrogen production rate, energy efficiency, and net power generation rate for the optimal case are determined as 1692 kg/h, 35.24 %, and 4269 kW, respectively. Also, the unit cost of hydrogen in the optimal case is obtained 1.49 $/kg which offers a cost-effective solution for hydrogen production. [Display omitted] • 4E analysis and optimization performed on a bio-waste driven polygeneration system. • Plant optimized using artificial neural network and multi-objective genetic algorithm. • The feasibility of integrating a membrane for hydrogen separation investigated. • The optimum exergy efficiency and total cost rate obtained 38.26 % and 58.17 M$/year. • Hydrogen and electricity cost of 1.49 $/kg and 0.0145 $/kWh achieved for optimal case. [ABSTRACT FROM AUTHOR]

Studies on the iodine-sulfur (IS) thermochemical cycle for hydrogen production has been carried out since about 2005 by the Institute of Nuclear and New Energy Technology, Tsinghua University, China. The HI decomposition occupies the important position of hydrogen generation in the IS cycle. In this paper, the HI-100 test apparatus with a H 2 production rate of 100 L/h was constructed and the HI decomposition was tested. First, the process and components for HI decomposition were designed. Then, the key components, including the feed tank, evaporator, gas heater, adiabatic reactor, condenser, and gas-liquid separator were made of industrial materials. After building this apparatus, the sealing test, heating water test, and HI decomposition have been conducted. The stable hydrogen production operation of more than 100 L/h had been achieved for 5 h, the maximum hydrogen production reached approximately 130 L/h, and the hydroiodic acid decomposition rate maintained about 22 %. The test results provide the design and experimental guidance for further amplification of HI decomposition for hydrogen production by the IS cycle. • The HI-100 test apparatus with the H 2 production rate of 100 NL/h was constructed. • An HI decomposition test for iodine-sulfur hydrogen production cycle was carried out. • The stable hydrogen production operation of above 100 L/h was achieved for 5 h. • The maximum hydrogen production rate reached about 130 L/h in HI-100 apparatus. • The hydroiodic acid decomposition rate maintained about 22 %. [ABSTRACT FROM AUTHOR]

The increasing trend towards global carbon neutrality is driving interest in ammonia fuel as a potential zero-carbon solution for transportation. However, due to the non-ideal combustion characteristics of ammonia, it is necessary to mix it with hydrogen to achieve better engine performance. While generating hydrogen from ammonia on-board is a key technology, there has been limited research in this area, which is hindering the introduction of ammonia engines to the market. This paper proposes an initial study on the feasibility of thermochemical fuel reforming (TFR) technology for generating hydrogen from ammonia fuel-rich operations. A zero-dimensional engine model, validated against experimental results, is used to assess the potential of the TFR approach and identify any barriers to implementation. The results indicate that the optimum air-fuel ratio for hydrogen generation is an equivalence ratio of two, as it maximizes hydrogen production rates while minimizing operational complexities. Moreover, increasing intake temperature, pressure, and compression ratio enhances hydrogen generation from the ammonia-rich mixture. However, owing to the limited reactivity of the ammonia fuel, the rate of hydrogen production remains relatively small (less than 1%/cycle), significantly falling short of the demand. Additionally, the combustion of the fuel-rich mixture in the TFR cylinder results in approximately 20%/cycle of hydrogen in the emitted gases, potentially enhancing the efficiency of working cylinders, but it also poses the risk of engine component failures due to the high pressure rise rate. In conclusion, the use of solely ammonia to produce hydrogen in the TFR cylinder proves to be inefficient, warranting further investigations into the potential benefits of incorporating additives to promote hydrogen production. Alternatively, if a catalyst is utilized to promote hydrogen production from ammonia, a separate electrically heated hydrogen generation system independently of the engine system proves to be more effective, allowing continuous hydrogen production, unlike the intermittent high-temperature environment provided by TFR technology. • Hydrogen production using in-cylinder thermochemical ammonia reforming is evaluated. • An air-ammonia ratio of ϕ = 2.0 is identified as optimal for hydrogen production. • Unfired conditions produce less than 1% of hydrogen in the exhaust per cycle. • Fired conditions can produce ∼20% of hydrogen in the emitted gases per cycle. • Extremely high pressure rise rates are implementation barriers for fired conditions. [ABSTRACT FROM AUTHOR]

ZnO/CuInS 2 composites were synthesized by using electrospun ZnO chain structures as a template, along with InCl 3 , CuCl 2 , and thiourea as sources of indium, copper, and sulphur, respectively. The ZnO/CuInS 2 core-shell structure enhances light absorption and carrier transport efficiency. Moreover, ZnO/CuInS 2 exhibits superior light absorption and photocatalytic hydrogen production performance compared to ZnO, with a peak hydrogen production of 4188.24 μmol g−1. The arrangement of energy levels within the ZnO/CuInS 2 heterojunction is the crucial factor in enhancing photocatalytic properties. Increased electrons distribution near the interface facilitates the transport performance of charge carriers, which accelerates hydrogen production kinetics at the interface, and promotes greater participation of photogenerated electrons and holes in catalytic reactions. Combined with the application of density functional theory, the computational analyses of work function and differential charge support this assertion. This paper introduces a fresh method for creating innovative photocatalysts and grasping the reaction mechanism involved in photocatalytic hydrogen generation. The ZnO/CuInS 2 heterojunction, encompassing CuInS 2 nanosheets surrounding ZnO nanofibers, displayed exceptional hydrogen production capacity. The most remarkable hydrogen production achievement was 4188.25 μmol g−1 in 6 h, a value more than 623.7 times superior to that of pure ZnO. The disparity in charge density highlighted the presence of significant charge transfer at the interface of ZnO/CuInS 2. This reinforces the fact that the ZnO/CuInS 2 construction and interface charge transfer are crucial in elevating its photohydrogen production capabilities. [Display omitted] • ZnO/CuInS 2 was synthesized by the electrospinning method. • The hydrogen production of heterojunction reached 4188.25 μmol g−1 in 6 h. • The mechanism was analyzed by DFT calculation. [ABSTRACT FROM AUTHOR]

The interest in nonthermal discharge plasma has recently increased over the last few decades due to the ability to generate new radicals at atmospheric pressure. This paper presents a comprehensive analysis of the dissociation processes and reaction rates of various water vapour samples by dielectric barrier discharge plasma (DBD). The influence of water contamination and the presence of ammonia (NH 3) on hydrogen production from water vapour was investigated. A novel reaction rate expression was proposed to fit the plasma-water vapour experiment results. The hydrogen production and conversion rate of pure reverse osmosis (RO) water samples showed greater results than the contaminated water samples in all experiments at different tested bubbling temperatures. The higher conversion rate was obtained from RO water combined with 1%NH 3 at a bubbling temperature of 50 °C and was 1.17%. The water contamination influenced the generated DBD plasma micro discharges, consequently decreasing the electron collisions, leading to lower water vapour conversion into constituent elements H 2 and O 2. It was also found that the influence of ammonia on the water vapour decomposition was related to the NH 3 concentration. Moreover, the reaction rate showed good agreement with the experimental results. It was observed that the energy efficiencies were obtained at an operating temperature of 50 °C for pure RO, GTW, and CTW water samples enhanced by adding 1%NH 3 , for example, the RO energy efficiency value at a bubbling temperature of 50 °C increased from 0.133% to 1.15% because of more hydrogen was generated. It implies that the water vapour decomposition processes are influenced by the following parameters: input gas temperature, reaction time, plasma power, oven or reactor heating temperature, the separation method, sampling method, and sampling collection time. [Display omitted] • The hydrogen production from various water types by DBD plasma is investigated. • The presence of ammonia enhanced the hydrogen production of water vapour. • The water contamination has a negative effect on the plasma water decomposition. • The new rate equation showed a good agreement with experimental results. [ABSTRACT FROM AUTHOR]

The majority of research in the carbon-based nanomaterials (CNMs) field has concentrated on the classification and synthesis of CNMs, with relatively few studies focusing on CNMs' roles in photocatalytic hydrogen production. CNMs have proven their potential as an effective addition to the appeal of photocatalytic hydrogen evolution because of their superior chemical and physical properties. This paper explores the recent advancements in photocatalytic hydrogen (H 2) production utilizing CNMs. As evidenced in the literature, carbon quantum dot (CQD)-sensitized titanium dioxide (TiO 2) can demonstrate to have a photocatalytic hydrogen generation activity of 472 mol g−1 h−1 and 1458 mol g−1 h−1 without and with loading metal co-catalyst (Pt). The optimum catalyst, 0.4 CQD/CdS, contributes to the highest H 2 production rate of 309 mmol g−1 h−1 (apparent quantum yield of 32.6%), which is 1.5 times greater than that of bare CdS. This would significantly accelerate the hydrogen production process. There are still challenges to reaching maximum photocatalytic hydrogen production, including low hydrogen storage. The overall price of hydrogen produced via photocatalysis is also higher because of the energy needed to store the hydrogen. Even though the problem is not directly related to the usage of CNMs, this restriction generates uncertainty and limits commercial investment. Given the rising demand for energy and the trend toward green power, it is recommended that extensive industrial uses of photocatalytic hydrogen produced by employing CNMs be investigated for better and more sustainable energy frameworks. • Recent advances in photocatalytic H 2 production are investigated utilizing CNMs. • The optimum catalyst, 0.4 CQD/CdS can produce the highest H 2 at 309 mmol g−1 h−1. • CQD-sensitized TiO 2 can generate 1458 mol g−1 h−1 photocatalytic hydrogen with Pt. • Photocatalytic H 2 production using CNMs should be investigated for industrial use. [ABSTRACT FROM AUTHOR]

The usage of Nanofluid to enhance heat transfer has been investigated by many researchers in small-scale heat transfers; however, in large-scale power plants, it has not been taken care of. In this research paper, a newly proposed energy system for hydrogen generation based on renewable sources is proposed and analyzed in detail. Unlike other power input systems, the vanadium chloride system generates hydrogen because it uses waste heat. In this regard, the nanoparticles of Al 2 O 3 and CuO are utilized in the main heat exchanger to enhance the heat transfer to the reactor of VCLC to generate more hydrogen. Also, the compound system has the gasifier-based internally fired gas turbine as the main system and can generate hydrogen in a more green way. The optimization based on deep learning methods is applied to seek the highest point of operation by the system. The results exhibit that Al 2 O 3 causes more heat transfer and efficiency enhancement, thus in hydrogen production, causing an increase of 18.5% compared to base fluid and 8.3% compared to CuO in H 2 Generation In circumstances when it is optimal, the values for exergetic efficiency and total hydrogen production are 64.5% and 4.5 kg/s respectively. In addition, using a nanofluid heat exchanger and biomass energy reduces CO 2 emissions to 0.91 kg/kWh. • Nanomaterial addition to Main heat exchanger in Power plant is investigated. • The enhancement in hydrogen generation by using nanoparticles is achived. • Performance assessment of system and deep learning based optimization is conducted. [ABSTRACT FROM AUTHOR]

Precooling technology is a widely used method for increasing the flight speed of turbojet engines. To solve the problems of oversized fuel tank and engine performance degradation caused by the low density of hydrogen fuel, a new precooled engine cycle based on hydrogen production technology from ammonia cracking is proposed. To evaluate the engine performances, a thermodynamic model and a test platform are established. The study shows that the test heat sink of ammonia is 4.12 MJ at 620.5 °C, and the upper boundaries of heat sink and hydrogen production rate of ammonia are higher than other chemical fuels. Besides, the optimized fuel ratio is set to 2.0, and the best compressor pressure ratio could be obtained at the point with the highest engine performances Further, the maximum flight Mach number of precooled engine is Ma 4.69, and compared with GE90 and J-58 engines, the carbon emission of precooled engine could be reduced by 94.15% and 72.95% respectively. Moreover, by increasing the cold storage degree, the engine performance can be further improved especially at high pressure ratio. Overall, the research of this paper is hopeful to provide a new idea and necessary theoretical support for the development of high-performance supersonic aero-engine. • A new precooled engine cycle based on hydrogen production technology is proposed. • The test heat sink of ammonia reaches 4.12 MJ at 620.5 °C. • The maximum flight Mach number of precooled engine is Ma 4.69. • The carbon emission of precooled engine could be reduced by 94.15%. • The method to improve the engine performances through clod storage is also proposed. [ABSTRACT FROM AUTHOR]

The paper presents a critical analysis of a commercial pre-feasibility study for hydrogen generation from sewage sludge generated in a wastewater treatment plant sized Population Equivalent (PE) = 160,000 Three commercial offers based on hydrothermal carbonization, gasification/plasma gasification and gas separation, are analysed and validated in terms of chemical reactions and energy balance. The obtained hydrogen yield equals 10 kg H 2 /Mg sludge for Technology#2 and 5.5 kg H 2 /Mg sludge for Technology#3, while the process efficiency equals 31.4% and 41.2%, respectively. The offer for Technology#1 is inconsistent. The potential market can be built in the transport sector, based on buses (8–12/day) or locomotives (1–2/day) and complemented by passenger cars (16–22/day). Hydrogen surplus can be disposed into the natural gas network at a city gate station, with target concentration <2%. Alternatively, it is possible to install a fuel cell unit for on-site electricity generation of 1780 MWh/a sold to the public grid. • Commercial technologies of hydrogen production from sewage sludge were studied. • Technologies of hydrothermal carbonization and plasma gasification were validated. • 1 of 3 commercial offers was found inconsistent regarding thermodynamics. • Hydrogen yield was found 5.5–10 kg/Mg sludge. • Process energy efficiency was found 31.4%–41.2%. [ABSTRACT FROM AUTHOR]

The aim of the paper is to examine the performance of molten carbonate fuel cell, which is supplied with a raw bioethanol, i.e. bioethanol which origins directly from fruit fermentation, without pre-treatment of fermentation products. The composition of raw bioethanol was precisely determined and then the impact of raw bioethanol on the degradation of molten carbonate fuel cells was examined. Steam to carbon ratio of the biofuel has been determined as 5.7 (in comparison to stoichiometry of reaction) which allowed for estimation of hydrogen production during steam reforming process taking place in the anode channel. The results in the form of current-voltage curve was obtained and compared with the same fuel cell fed with pure hydrogen, while the amount of hydrogen was defined as identical with the one after steam reforming of biofuel taking place in the nickel anode channel. Relevant literature studies were focused on the purified fuel or examination of the impact of individual components. Our study proved carbon deposition is not a problem, however solid particles contamination in fermentation product makes it impossible to use fuel cell fueled with fermentation product for longer periods, and prior to supplying fuel cell the bioethanol purification is required. A raw biofuel with its impurities did not have any impact on the anode and current collector surface from physical point of view, but Electrochemical Impedance Spectroscopy analysis shows visible increase of ohmic loses. • Homemade first generation bioethanol composition have been examined. • Manufactured bioethanol has been delivered directly to the MCFC anode without purification. • Performance of MCFC fueled with impure bioethanol has been investigated. • Effect of steam reforming for hydrogen generation and steam to carbon ratio were evaluated. • Pollution on the anode after cell operation was investigated with SEM and EIS. [ABSTRACT FROM AUTHOR]

The work is devoted to the development of a thermal scheme for the conversion of a cogeneration power plant to threegeneration with the production of hydrogen as a new product. The purpose of the work is to assess the possibility and potential of hydrogen production from MSW at the existing thermal power plants of St. Petersburg. To achieve this goal, it is necessary to develop a methodology for selecting the site of an existing thermal power plant in order to integrate a hydrogen production complex by the MSW gasification method, as well as a methodology for estimating the amount of hydrogen that can potentially be obtained from a given amount of MSW. The research methods include simulation of the thermal circuit of a steam power plant in the United Cycle program. The paper proposes an algorithm for selecting the site of an operating thermal power plant for the integration of a complex for the production of hydrogen by the method of MSW gasification. The algorithm can be applied to any subjects of the Russian Federation, and its relevance is confirmed by strategic documents. Potential locations for the new TPP are being considered in the territories of TPP-21 and TPP-22, which have the necessary resources and good infrastructure. As a result of the study, the site of TPP-22 was selected as the most suitable for the placement of new facilities. A new thermal scheme of a threegeneration power plant has been developed, including a hydrogen generation unit by the MSW gasification method. This allows the production of hydrogen in parallel with the production of electricity and heat. The efficiency evaluation criterion is the fuel heat utilization factor (FHUF). Regardless of the hydrogen content in the generated synthesis gas, the integration of the synthesis gas cooler into the thermal circuit of the TPP leads to an increase in the FHUF and an additional energy effect. This scheme increases the efficiency of existing TPP plants, regardless of the morphological composition of municipal solid waste. [ABSTRACT FROM AUTHOR]

This paper presents a novel energy management strategy (EMS) to control a wind-hydrogen microgrid which includes a wind turbine paired with a hydrogen-based energy storage system (HESS), i.e., hydrogen production, storage and re-electrification facilities, and a local load. This complies with the mini-grid use case as per the IEA-HIA Task 24 Final Report, where three different use cases and configurations of wind farms paired with HESS are proposed in order to promote the integration of wind energy into the grid. Hydrogen production surpluses by wind generation are stored and used to provide a demand-side management solution for energy supply to the local and contractual loads, both in the grid-islanded and connected modes, with corresponding different control objectives. The EMS is based on a hierarchical model predictive control (MPC) in which long-term and short-term operations are addressed. The long-term operations are managed by a high-level MPC, in which power production by wind generation and load demand forecasts are considered in combination with day-ahead market participation. Accordingly, the hydrogen production and re-electrification are scheduled so as to jointly track the load demand, maximize the revenue through electricity market participation and minimize the HESS operating costs. Instead, the management of the short-term operations is entrusted to a low-level MPC, which compensates for any deviations of the actual conditions from the forecasts and refines the power production so as to address the real-time market participation and the short time-scale equipment dynamics and constraints. Both levels also take into account operation requirements and devices' operating ranges through appropriate constraints. The mathematical modeling relies on the mixed-logic dynamic (MLD) framework so that the various logic states and corresponding continuous dynamics of the HESS are considered. This results in a mixed-integer linear program which is solved numerically. The effectiveness of the controller is analyzed by simulations which are carried out using wind forecasts and spot prices of a wind farm in center-south of Italy. • Design of control algorithms for islanded and grid-connected microgrids. • Development of hierarchical MPCs to target long-term and short-term operations. • Tracking the load demand and maximizing the revenue via electricity markets. • Minimization of the HESS operational costs. [ABSTRACT FROM AUTHOR]

The hybrid thermochemical copper-chlorine (Cu–Cl) cycle for water splitting, developed as a novel approach to produce green hydrogen, has gained greater attention. A series of close-loop reactions makes the process environmentally friendly. A newly developed hybrid six-step Cu–Cl cycle consists of thermochemical, electrochemical, and a unit operation of spray drying. The present paper analyzes the configuration of the six-step Cu–Cl cycle thermodynamically. Studies on many factors are carried out to determine the cycle's total energy and exergy efficiency. The modeling and simulation of the six-step process was done by Aspen Plus. The six-step cycle was found to have an energy and exergy efficiency of 38.94 % and 52.74 %, respectively. The effect on exergetic efficiency with ambient temperature and cycle temperature variation was also investigated. The enhancement in the effectiveness of six steps Cu–Cl cycle could be possible from the current study analysis using thermal recovery and minimizing exergy destructions. [Display omitted] • Thermodynamic evaluation of novel ICT-OEC copper-chlorine thermochemical cycle. • An investigation based on mass, energy, and exergy balances. • The energy and exergy efficiency of the overall system is 38.94 % and 52.74%, respectively. • The hydrogen production rate of the system is 0.002 kg/s. [ABSTRACT FROM AUTHOR]

Hydrogen is expected to be a key energy carrier in the global energy transition. A promising method of hydrogen production is water electrolysis powered by nuclear energy. This energy source can also be used in other hydrogen production technologies, such as copper-chlorine cycle. Proper comparison of various hydrogen production methods from the sustainability perspective requires the use of analysis in a global balance boundary. The paper presents a comparison of sustainability of various hydrogen generation methods, with emphasis on the methods exploiting nuclear energy. Instead of local energy efficiency, the index of Thermo-Ecological Cost (TEC) is proposed. TEC is a measure of the depletion of non-renewable resources burdening the production of a given product. Other criteria used in the assessment are: availability of energy supply (capacity factor), cumulative greenhouse gas emissions and resources to production ratio. In addition, water electrolysis and copper-chlorine cycle have been considered cogeneration processes, providing oxygen as a useful by-product. Taking into account all the criteria suggests that obtaining hydrogen with the use of nuclear technologies will provide a fair, long-term compromise compared to other hydrogen generation technologies. • Sustainability of H 2 production methods utilizing nuclear energy is investigated. • Technologies are evaluated in global balance boundary using Thermo-Ecological Cost. • Multiple criteria are applied to properly compare hydrogen production methods. • Nuclear-based H 2 can be considered more sustainable than renewable-based H 2. [ABSTRACT FROM AUTHOR]

The reaction of aluminum water to produce hydrogen is prevented by an alumina film. To prepare a kind of aluminum alloy with instant hydrogen production and high hydrogen yield, this paper investigates the effect of different Ga content and In–Sn ratio on the hydrogen production performance of aluminum alloy, and also observes the effect of hydrogen production at different temperatures. The composition, structure, and thermal properties are observed by Scanning Electron Microscope, X-ray diffraction, and differential scanning calorimetry. With different ratios of In and Sn, they appear as two intermetallic compounds, In 3 Sn and InSn 4. When Ga, In, and Sn were added to aluminum together, the hydrolytic properties of the Al-Ga-In-Sn alloys are greatly improved. The paper finally prepared an aluminum alloy with a hydrogen conversion rate of more than 98% and activation energy of 39.2 kJ/mol. Further the development and utilization of hydrogen energy are promoted. [Display omitted] • A high hydrogen yielding aluminum alloy prepared by melting was proposed. • The hydrolysis rate is proportional to the reaction temperature. • Effect of Ga content and In–Sn ratio on hydrogen production performance. • Effect of low melting point elements on the activation energy of aluminum alloys. • The activation energy of Al-3%Ga-5.25%In-1.75%Sn is 39.2 kJ/mol. [ABSTRACT FROM AUTHOR]

Considering the high calorific value and low-carbon characteristics of hydrogen energy, it will play an important role in replacing fossil energy sources. The production of hydrogen from renewable energy sources for electricity generation and electrolysis of water is an important process to obtain green hydrogen compared with classic low-carbon hydrogen production methods. However, the challenges in this process include the high cost of liquefied hydrogen and the difficulty of storing hydrogen on a large scale. In this paper, we propose a new route for hydrogen storage in metals, namely, electricity generation from renewable energy sources, electrolysis to obtain metals, and subsequent hydrogen production from metals and water. Metal monomers facilitate large-scale and long-term storage and transportation, and metals can be used as large-scale hydrogen storage carriers in the future. In this technical route, the reaction between metal and water for hydrogen production is an important link. In this paper, we systematically summarize the research progress, development trend, and challenges in the field of metal to hydrogen production. This study aim to aid in the development of this field. • A new route for hydrogen storage and production via metals on a large scale is proposed. • Electrolysis to obtain metals by green electricity, and subsequent hydrogen production from metals and water. • Metal monomers facilitate large-scale and long-term storage and transportation. • Metals can be used as large-scale hydrogen storage carriers in the future. • Metal-water hydrogen production can make full use of renewable energy without carbon dioxide. [ABSTRACT FROM AUTHOR]

The study presents a novel integrated three-compartment electrochemical continuous electrodeionization reactor that was constructed in a laboratory environment. In order to extract large amounts of carbon dioxide from naturally occurring oceanwater in the form of bicarbonate and carbonate, it develops a innovative electrolytic cation exchange process. At the same time, it produces hydrogen gas for possible hydrocarbon synthesis. The study employs the Box-Behnken experimental design approach implemented through the Design Expert software to investigate and optimize the performance of electrochemical hydrogen extraction from Ocean water from an integrated reactor. The integrated electrochemical continuous-type electrodeionization reactor comprises two cation-permeable membranes that operate as boundaries between three compartments: a central compartment and electrode compartments that house the cathode and anode, each of which may reverse polarity. These membranes are made of gel polystyrene cross-linked with divinylbenzene, which has acidic properties that allow cation transport while inhibiting anions. The integrated reactor's electrode chambers are enclosed in plexiglass end plates and contain distinct Plexiglass electrode compartments. These compartments have mesh and solid steel anode and cathode electrodes, with an electrode active area of 176.71 cm2. The influence of various factors, such as voltage and electrolyte amount, on the production of hydrogen synthesis is examined. The study results demonstrate a maximum hydrogen production rate of 2.2 mg/min and a hydrogen production efficiency of 7.82%. The lab testing was carried out using experimental equipment to determine viability. The tests included 35-min runs that measured hydrogen generation under various parameters, such as applied voltage, electrolyte concentration, and pH levels. The ocean salt solutions of 0.5M, 1M, and 2M were initially prepared and evaluated for hydrogen generation. Each concentration is assessed at a voltage range of 4–15V, with matching solution pH values ranging from 2 to 7. Optimization studies were conducted to enhance the hydrogen production rate. The results indicate that hydrogen production rises proportionally with applied voltage and electrolyte concentration but falls with pH growth. Within the Design Expert software, the statistical methods for response surface analysis and optimization are utilized accordingly. • The paper develops an integrated three-compartment system for hydrogen production. • The paper investigates the system overall efficiencies for assessment. • It discusses how varying voltage and concentration affects hydrogen production. [ABSTRACT FROM AUTHOR]