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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]

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]

Solar-driven water splitting by inorganic semiconductor photocatalysts is considered a promising method to produce hydrogen fuel. Loading inorganic semiconductor on cellulose fiber to construct photocatalytic paper contributes to the dispersion and recycling of photocatalyst. In addition, the photocatalytic paper floating on water can build a solid–gas biphase photocatalytic interface (photothermal-generated steam/photocatalytic paper/hydrogen), replacing the traditional liquid–solid–gas triphase photocatalytic interface (liquid water/photocatalyst/hydrogen) for improving photocatalytic kinetics. Here, we design and synthesize a photocatalytic composite paper with zinc sulfide (ZnS) anchored onto cellulose fibers (CF) with the help of polydopamine (PDA). PDA achieves high load and uniform distribution of ZnS on cellulose fibers, and forms the ZnS/PDA heterojunction to increase photogenerated charge separation efficiency and photocatalytic stability. Solid–gas biphase photocatalytic interface constructed by the CF/PDA/ZnS composite paper minimizes the interface barriers of hydrogen transport and water molecular adsorption for improving hydrogen evolution rate. The CF/PDA/ZnS composite paper shows a high hydrogen production rate up to 18706.8 μmol h−1 g−1. Stable loading of ZnS/PDA heterojunction in composite paper contributes to the photocatalytic stability. In the third photocatalytic cycle, the hydrogen evolution rate of CF/PDA/ZnS composite paper remains 96.4%. This work inspires that anchoring of inorganic semiconductor on cellulose fibers with the help of PDA can be a promising strategy for designing efficient photocatalytic paper for solar hydrogen production. [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]

This paper presents the results of a severe accident parametric sensitivity study performed on a model of a generic integral pressurized water reactor (iPWR). The analyzed sequence is a loss of coolant accident (LOCA)-type scenario, postulating that safety systems are not available. In this work, a MELCOR 2.2 input deck of a generic iPWR was developed based on publicly available data. The iPWR used in this work is a generic iPWR with a thermal power of about 160 MWth, characterized by a compact steam generator and a submerged containment configuration. A hypothetical scenario considered in this work was an unmitigated small break LOCA leading to a severe accident with partial core degradation, due to the postulated assumptions. In the presented paper, 16 sensitivity cases were calculated and analyzed, focusing mainly on heat transfer, decay heat, and core degradation parameters. The selected parameters and their combination caused partial core degradation and showed significant differences in investigated variables such as core degradation and hydrogen generation, as well as examined CPU time consumption. This a preparatory work performed in the framework of the Horizon Euratom SASPAM-SA project, which aims to investigate the applicability and transfer of the operating large light-water reactor knowledge and know-how to the iPWR, taking into account European licensing analysis needs for the severe accident and emergency planning zone. [ABSTRACT FROM AUTHOR]

As new sources of energy and advanced technologies are used, there is a continuous evolution in energy supply, demand, and distribution. Advanced nuclear reactors and clean hydrogen have the opportunity to scale together and diversify the hydrogen production market away from fossil fuel-based production. Nevertheless, the technical uncertainties surrounding nuclear hydrogen processes necessitate thorough research and a solid development effort. This paper aims to position pink hydrogen for nuclear hydrogen production at the forefront of sustainable energy-related solutions by offering a comprehensive review of recent advancements in nuclear hydrogen production, covering both research endeavors and industrial applications. It delves into various pink hydrogen generation methodologies, elucidating their respective merits and challenges. Furthermore, this paper analyzes the evolving landscape of pink hydrogen in terms of its levelized cost by comparatively assessing different production pathways. By synthesizing insights from academic research and industrial practices, this paper provides valuable perspectives for stakeholders involved in shaping the future of nuclear hydrogen production. [ABSTRACT FROM AUTHOR]

The global issue of climate change caused by humans and its inextricable linkage to our present and future energy demand presents the biggest challenge facing our globe. Hydrogen has been introduced as a new renewable energy resource. It is envisaged to be a crucial vector in the vast low-carbon transition to mitigate climate change, minimize oil reliance, reinforce energy security, solve the intermittency of renewable energy resources, and ameliorate energy performance in the transportation sector by using it in energy storage, energy generation, and transport sectors. Many technologies have been developed to generate hydrogen. The current paper presents a review of the current and developing technologies to produce hydrogen from fossil fuels and alternative resources like water and biomass. The results showed that reformation and gasification are the most mature and used technologies. However, the weaknesses of these technologies include high energy consumption and high carbon emissions. Thermochemical water splitting, biohydrogen, and photo-electrolysis are long-term and clean technologies, but they require more technical development and cost reduction to implement reformation technologies efficiently and on a large scale. A combination of water electrolysis with renewable energy resources is an ecofriendly method. Since hydrogen is viewed as a considerable game-changer for future fuels, this paper also highlights the challenges facing hydrogen generation. Moreover, an economic analysis of the technologies used to generate hydrogen is carried out in this study. [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 utilization of coal for hydrogen generation presents a multifaceted approach employing processes like coal gasification, pyrolysis, or high-temperature steam reforming. These methodologies entail reacting coal with steam or oxygen under elevated temperatures, yielding a gas mixture comprising hydrogen, carbon monoxide, and various byproducts. This paper delves into the exploration of hydrogen generation from coal, highlighting techniques such as gasification, pyrolysis, and other emerging methods. Notably, hydrogen discoveries within coal basins have garnered significant attention due to their implications for energy production and environmental sustainability. Certain coal basins harbor deposits rich in hydrogen, surpassing conventional coal reserves in their hydrogen content. These hydrogen-rich coals, including select sub-bituminous and lignite varieties, offer promising avenues for hydrogen production and utilization. However, the utilization of coal for hydrogen generation is not without its challenges. Technical hurdles, such as process efficiency and environmental concerns, demand rigorous investigation and innovative solutions. This paper addresses the challenges faced in coal-based hydrogen generation while elucidating the potential future prospects. It explores avenues for enhancing process efficiency, mitigating environmental impacts, and integrating coal-based hydrogen generation into broader energy strategies. Moreover, it underscores the importance of interdisciplinary research and collaboration in unlocking the full potential of coal for sustainable hydrogen production. [ABSTRACT FROM AUTHOR]

Copper-based catalysts are widely used in methanol steam reforming to produce hydrogen. In this paper, the supportive effect of the crystal phase of ZrO2 on Cu-based catalysts in methanol steam reforming is discussed. Monoclinic(m-), Tetragonal(t-) and mixed ZrO2 phases were prepared, and structure–activity relationships were investigated with XRD, H2-TPR, BET, HR-TEM and XPS. It was found that the catalyst with a 81.4% monoclinic ZrO2 crystal phase exhibited the highest methanol conversion (88.5%) and the highest hydrogen production rate (104.6 μmol/gcat·s) at 275 °C as it displayed the best reducing properties and more oxygen vacancies on the catalyst surface. Oxygen vacancies can produce more Cu1+ + Cu0, which is the active species for methanol steam reforming on the catalyst surface, and therefore affect catalytic activity. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) technology in marine engineering holds significant importance due to its potential to address various challenges in the marine environment. Currently, PEC-type applications in marine engineering offer numerous benefits, including sustainable energy generation, water desalination and treatment, photodetection, and communication. Finding novel efficient photoresponse semiconductors is of great significance for the development of PEC-type techniques in the marine space. Bismuth-based semiconductor materials possess suitable and tunable bandgap structures, high carrier mobility, low toxicity, and strong oxidation capacity, which gives them great potential for PEC-type applications in marine engineering. In this paper, the structure and properties of bismuth binary and mixed-anion semiconductors have been reviewed. Meanwhile, the recent progress and synthetic approaches were discussed from the point of view of the application prospects. Finally, the issues and challenges of bismuth binary and mixed-anion semiconductors in PEC-type photodetection and hydrogen generation are analyzed. Thus, this perspective will not only stimulate the further investigation and application of bismuth binary and mixed-anion semiconductors in marine engineering but also help related practitioners understand the recent progress and potential applications of bismuth binary and mixed-anion compounds. [ABSTRACT FROM AUTHOR]

Owing to the massive expansion and intermittent nature of renewable power, green hydrogen production, storage, and transportation technologies with improved economic returns need to be developed. Moreover, the slowness of the dehydrogenation reaction is a primary barrier to the commercialization of liquid organic hydrogen carrier (LOHC) technology. The present study focused on increasing the speed of dehydrogenation, resulting in the proposal of a triple-loop dehydrogenation system comprising reaction, heating, and chilling loops. The reactor has a rotating cage containing a packed bed of catalyst pellets, which is designed to enhance both heat and mass transfer by helping to detach precipitated hydrogen bubbles from the catalyst surface. In addition, the centrifugal force aids in isolating the gas phase from the LOHC liquid. A dehydrogenation experiment was conducted using the reaction and chilling loops, which revealed that the average hydrogen production rate during the first hour was 52.6 LPM (liter per minute) from 26.3 L of perhydro-dibenzyl-toluene with 1.5 kg of 0.5 wt% Pt/Al2O3 catalyst. This was approximately 48% more than the value predicted with the reaction kinetics measured with a small-scale plug flow dehydrogenation reactor with less than 1.0 g of 5.0 wt% Pt/Al2O3 catalyst. The concept, construction methods, and results of the preliminary gas infiltration, flow visualization, and reactor pumping experiments are also described in this paper. [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]

With the current trends of wind energy already playing a major part in the Scottish energy supply, the capacity of wind farms is predicted to grow exponentially and reach further depths offshore. However, a key challenge that presents itself is the integration of large producing assets into the current UK grid. One potential solution to this is green hydrogen production, which is being heavily researched in industry, with many concepts being investigated for large-scale purposes. However, the operations and maintenance (O&M) costs and availability of green hydrogen systems need to be quantified to ensure economical and technical viability, which is sparse in the available literature. The study presented in this paper investigated the availability and O&M costs of coupled wind–hydrogen systems by attempting to quantify the failure rates, repair times, repair costs and number of technicians required for key green hydrogen components. This study also utilised an O&M model created by the University of Strathclyde, which uses Monte Carlo Markov chain simulations to produce the O&M outputs. A number of assumptions were made throughout the study in relation to the O&M model inputs, and the baseline availability for the coupled wind–hydrogen system was 85.24%. Whilst the wind turbine still contributed a major part to the downtime seen in the simulations, the combined hydrogen system also contributed a significant amount, a total of 37%, which could have been due to the technology readiness levels of some the components included in the hydrogen system. [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]

This paper addresses the problem of hydrogen generation from hydrocarbon gases using Steam Methane Reforming (SMR) with byproduct CO2 injected into and stored in a partially depleted oil reservoir. It focuses on the reservoir aspects of the problem using numerical simulation of the processes. To this aim, a numerical model of a real oil reservoir was constructed and calibrated based on its 30-year production history. An algorithm was developed to quantify the CO2 amount from the SMR process as well as from the produced fluids, and optionally, from external sources. Multiple simulation forecasts were performed for oil and gas production from the reservoir, hydrogen generation, and concomitant injection of the byproduct CO2 back to the same reservoir. EOR from miscible oil displacement was found to occur in the reservoir. Various scenarios of the forecasts confirmed the effectiveness of the adopted strategy for the same source of hydrocarbons and CO2 sink. Detailed simulation results are discussed, and both the advantages and drawbacks of the proposed approach for blue hydrogen generation are concluded. In particular, the question of reservoir fluid balance was emphasized, and its consequences were presented. The presented technology, using CO2 from hydrogen production and other sources to increase oil production, also has a significant impact on the protection of the natural environment via the elimination of CO2 emission to the atmosphere with concomitant production of H2. [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]

Green hydrogen, produced by water electrolysis with renewable energy, plays a crucial role in the revolution towards energy sustainability, and it is considered a key source of clean energy and efficient storage. Its ability to address the intermittency of renewable sources and its potential to decarbonize sectors that are difficult to electrify make it a strategic component in climate change mitigation. By using a method based on a bibliometric review of scientific publications, this paper represents a significant contribution to the emerging field of research on green hydrogen and provides a detailed review of electrolyzer technologies, identifying key areas for future research and technology development. The results reflect the immaturity of a technology which advances with different technical advancements, waiting to find the optimal technical solution that allows for its massive implementation as a source of green hydrogen generation. According to the results found in this article, alkaline (ALK) and proton exchange membrane (PEM) electrolyzers seem to be the ones that interest the scientific community the most. Similarly, in terms of regional analysis, Europe is clearly committed to green hydrogen, in view of the analysis of its scientific results on materials and electrolyzer capacity forecasts for 2030. [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]

In the pursuit of sustainable hydrogen production via water electrolysis, paramount importance of electrocatalyst stability emerges as a defining factor for long‐term industrial viability. A thorough understanding and enhancement of stability not only ensure extended catalyst lifetimes but also pave the way for consistent and efficient hydrogen generation. This review focuses on the pivotal role of stability in determining the practical viability of oxygen evolution electrocatalysts (OECs) for large‐scale applications in water electrolysis for hydrogen production. The paper explores the pivotal role of stability over initial activity, citing examples and hypothetical scenarios. First, figures of merits for stability evaluation of the electrocatalyst are explained along with the available benchmarking protocols for stability evaluation. Further, the text delves into various strategies that can enhance the stability of the electrocatalyst which include self‐healing/regeneration pathway, oxygen evolution reaction (OER) mechanism optimization to achieve highly stable OER and stabilization of active metals atoms within the electrocatalyst to inhibit dissolution as a way forward for industrial application. The interplay of stability, activity, and cost is also explained to suit the industrial application of the electrocatalyst. Lastly, it outlines challenges, prospects, and future directions, presenting a guide for advancing OECs in the hydrogen generation landscape. [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]

Element doping and construction of heterojunction composites are the most common ways to enhance g-C3N4, which are very attractive in achieving high photocatalytic activity. In this study, 2D nanosheet structured BCN was obtained by doping B atoms with graphite carbon nitride. Subsequently, Ti MOFs were loaded on BCN to obtain a Z-scheme heterojunction composite TBCN through calcination. Under simulated sunlight, the photocatalytic hydrogen production rate of the TBCN heterostructure was 1242 μmol h−1 g−1, which was 2.2 times higher than that of BCN and 9.34 times higher than that of bulk graphite carbon nitride (GCN). Experimental results showed that the construction of a Z-scheme heterojunction composite (TBCN) could effectively adjust the material band gap position, expand the light absorption range, enhance electron transfer and inhibit electron–hole recombination, which are crucial for efficient photocatalysis. This study not only provides a strategy for constructing heterojunction composites in the field of g-C3N4 photocatalytic hydrogen evolution, but also deeply analyzes the electron migration direction and the reasons for enhancing carrier separation in the Z-type heterojunction scheme, thus providing potential guidance for future research. [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]

Exploring efficient non-noble metal catalysts for the hydrogen evolution reaction (HER) will contribute to the development of clean and green energy technologies. Herein, we adopted a "waste utilization" strategy by using readily available and inexpensive coconut shell waste as a carbon source to synthesize carbon materials anchored with a Cu7Co alloy (Cu7Co/C) as a potential electrocatalyst for the hydrogen evolution reaction (HER). Utilizing a combination of hydrothermal and pyrolysis methods, the synthesized Cu7Co/C catalyst showcases superior HER electrocatalytic performance in alkaline solutions, with an overpotential of 134 mV at 10 mA cm−2 and a Tafel slope of 94 mV dec−1. The alloying of Cu and Co within Cu7Co/C markedly improves charge transfer capabilities, enhancing HER electrocatalysis. This research underscores the exceptional catalytic performance and stability of Cu7Co/C nanocomposites in alkaline media for the HER, attributed to a synergistic effect between the carbon derived from coconut shells and the bimetallic Cu7Co alloy. [ABSTRACT FROM AUTHOR]

NaBH4 is an attractive candidate for closed-loop hydrogen generation in small practical applications owing to its ambient condition hydrogen release mechanism, non-toxic byproduct, ability to regenerate, and stability at ambient conditions. The hydrolysis of NaBH4 requires a catalyst to accelerate the hydrogen generation process and cobalt oxide is one such promising catalyst in this reaction. The surface species and crystalline phases of cobalt oxide catalysts play an important role in determining the hydrogen generation rate and overall hydrolysis process. In this study, cobalt oxide nanoparticles are synthesized by a thermal plasma route. The two crystalline phases, namely c-CoO and Co3O4, are tuned using thermal plasma operating conditions. The catalysts so obtained have been thoroughly characterized using analytical techniques like XRD, XPS, HR-TEM, etc. Furthermore, the catalyst was used for hydrogen production in the hydrolysis process of NaBH4. The ex situ X-ray photoelectron spectra recorded at different stages of the hydrolysis process have been extensively used to understand surface modifications occurring at the surface of the catalyst. The Co+3/Co+2 ratio and attachment of other species during hydrolysis analyzed using XPS are correlated with the overall hydrolysis reaction before and after catalysis. It was concluded that the presence of the c-CoO (i.e. initial Co+2 species presence) phase brings stability to hydrogen production in that cycle. [ABSTRACT FROM AUTHOR]

Electrocatalytic hydrogen generation in alkaline medium has become widely used in a variety of sectors. However, the possibility for additional performance improvement is hampered by slow kinetics. Because of this restriction, careful control over processes such as water dissociation, hydroxyl desorption and hydrogen recombination is required. Covalent organic frameworks (COFs) based on porphyrin and polyoxometalates (POMs) show encouraging electrocatalytic performance, offering a viable route for effective and sustainable hydrogen generation. Their specific architectures lead to increased electrocatalytic activity, which makes them excellent choices for developing water electrolysis as a clean energy conversion method in the alkaline medium. In this regard, TTris@ZnPor and Lindqvist POM were coordinated to create a new eco-friendly and highly active covalent organic framework (TP@VL-COF). In order to describe TP@VL-COF, extensive structural and morphological investigations were carried out through FTIR, 1H NMR, elemental analysis, SEM, fluorescence, UV-visible, PXRD, CV, N2-adsorption isotherm, TGA and DSC analyses. In an alkaline medium, the electrocatalytic capability of 20%C/Pt, TTris@ZnPor, Lindqvist POM and TP@VL-COF was explored and compared for the hydrogen evolution reaction (HER). The TP@VL-COF showed the best catalytic efficiency for HER in an alkaline electrolyte, requiring just a 75 mV overpotential to drive 10 mA cm−2 and outperforming 20%C/Pt, TTris@ZnPor, Lindqvist POM and other reported catalysts. The Tafel slope value also indicates faster kinetics for TP@VL-COF (114 mV dec−1) than for 20%C/Pt (182 mV dec−1) TTris@ZnPor (116 mV dec−1) and Lindqvist POM (125 mV dec−1). [ABSTRACT FROM AUTHOR]

In this work, CoV-LDH/ZnIn2S4 (CoV-LDH/ZIS) nanocomposites were synthesized through a self-assembly process in order to investigate the influence of CoV-LDH addition on the rate of hydrogen production. XRD and TEM measurements confirmed the effective preparation of CoV-LDH/ZIS nanocomposites. Among all the nanocomposite photocatalysts, 2.0%-CoV-LDH/ZIS showed the best photocatalytic performance with a hydrogen production rate of 1397.3 μmol g−1 h−1, approximately 2.2 times that of pure ZnIn2S4 (ZIS). The X-ray photoelectron spectroscopy (XPS) measurement indicated that there is a strong interfacial interaction between ZIS and CoV-LDH, indicating that more than simple mechanical mixing had occurred. The steady-state fluorescence spectroscopy (PL) and time-resolved photoluminescence (TRPL) spectroscopy results showed that the electron and hole recombination in CoV-LDH/ZIS is significantly reduced and that efficient interface charge transfer and separation are achieved. This work sheds light on the interfacial electron transfer between two semiconductor materials, which promotes the separation of photogenerated carriers and thus enhances photocatalytic hydrogen production activity. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) materials, renowned for their high specific surface area, excellent conductivity, and customizable functional groups, are widely employed as catalyst carriers. However, enhancing the activity of Ru-based catalysts supported on AC (Ru/AC) for ammonia decomposition remains a challenge. In this study, commercial AC was utilized as a substrate, with glucose and urea employed as modifiers. Specifically, the surface of the AC was modified via a hydrothermal pyrolysis method, resulting in the successful post-treatment in situ co-doping of nitrogen (ACGN). Experimental results revealed that Ru/AC-GN exhibited a hydrogen production rate 46% higher than that of Ru/AC at 475 °C, indicating improved activity and stability. The characterization of AC-GN demonstrated that nitrogen doping primarily occurred on the external surface and macropores of the AC, increasing the nitrogen content in the carrier, particularly pyrrolic nitrogen content, while preserving the original structural and morphological integrity of the AC. The enhanced dispersion of Ru, combined with the improved electronic transmission capabilities and strengthened interactions between the metal and the modified carrier, were identified as pivotal factors contributing to the enhanced lowtemperature efficacy of Ru/AC-GN. This paper presents a novel direction for the large-scale preparation of efficient catalysts for ammonia decomposition. [ABSTRACT FROM AUTHOR]

Finding efficient photocatalysts is the key to achieving sustainable hydrogen production. In this work, a rational design of Cd2+-doped Zn3In2S6 (ZIS) and a heterojunction structure with g-C3N4 (GCN) was carried out to form a GCN/Cd/ZIS composite. The synergistic effect of Cd2+ doping and heterojunction construction in the photocatalytic hydrogen production process was probed. The results showed that doping Cd2+ modified the bandgap structure of ZIS and improved the photocatalytic activity. The heterojunction construction between Cd/ZIS and GCN also effectively promoted the separation and migration of photogenerated carriers, which significantly improved the hydrogen production performance of the GCN/Cd/ZIS composite. The hydrogen production rate of 15% Cd/ZIS and 5% GCN/Cd/ZIS was 2.45 mmol g−1 h−1, 3.34 mmol g−1 h−1, which was 4.3 and 5.9 times higher than that of ZIS (0.57 mmol g−1 h−1), respectively. This study provides strong evidence that doping and heterojunction construction can synergistically improve photocatalytic activity. [ABSTRACT FROM AUTHOR]

Hydrazine borane (HB) has been considered to be an excellent medium for hydrogen storage, but the development of efficient catalysts for controllable and complete hydrolytic dehydrogenation of HB remains a severe challenge. In this study, a novel catalyst consisting of Ni0.6Pt0.4 nanoparticles supported on phosphorus-doped reduced graphene oxide (P-rGO) is readily obtained via a simple co-reduction method and serves as a highly efficient and stable catalyst toward the complete hydrolytic dehydrogenation of HB. Compared with Ni0.6Pt0.4/rGO, the as-prepared Ni0.6Pt0.4/P-rGO catalyst exhibits much higher catalytic activity for HB dehydrogenation, providing a total turnover frequency (TOF) value of 2419.4 h−1 at 323 K, which surpasses that of the majority of reported catalysts. Meanwhile, it also exhibits lower activation energy (Ea) and better recycle stability. The reason for the outstanding catalytic performance of Ni0.6Pt0.4/P-rGO could be attributed to the combined influence of small particle sizes, the enhanced synergistic effects of NiPt nanoparticles and the P-rGO substrate, the electronic interaction between Ni and Pt, and the NaOH promotion effect. This work provides an innovative approach to construct highly efficient and robust catalyst systems using simple and controllable methods. [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]

Developing highly active and stable non-noble-metal cocatalyst-decorated semiconductors is desirable for the practical application of photocatalysis, which remains an open question. Herein, we report transition-metal nitride (Ni3FeN) loaded cadmium sulfide (CdS) nanorods prepared through a simple hydrothermal method and surface treatment with NH3. The as-prepared photocatalyst Ni3FeN (3 wt%)/CdS showed a hydrogen evolution rate of 4.6 mmol g−1 h−1, which was 23.8 and 6.8 fold higher than those of CdS and Pt (1 wt%)/CdS, respectively. The Ni3FeN/CdS sample exhibited remarkable stability for seven consecutive cycles of photocatalytic tests lasting 21 hours. It was confirmed through Kelvin probe measurements that a Schottky junction between Ni3FeN and CdS gave rise to the inhibited recombination of photogenerated carriers, which benefited the photocatalytic HER 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]

This study developed an efficient photocatalyst for hydrogen production, consisting of CdS nanorods and the CoTPPBr4 co-catalyst. The synthesized photocatalyst was characterized using a suite of techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), photoluminescence (PL) spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Additionally, transient photocurrent response and electrochemical impedance spectroscopy (EIS) were carried out to further probe the material's properties. Our findings demonstrate that the CoTPPBr4 co-catalyst significantly enhances the photocatalytic H2 evolution efficiency under visible light irradiation. Notably, among the tested photocatalysts, a 12.5% CoTPPBr4/CdS composite exhibited the most superior photocatalytic performance, achieving a hydrogen production rate of 41.3 mmol g−1 h−1, which is 4.1 times higher than that of pristine CdS. The introduction of CoTPPBr4 effectively facilitates charge transfer within CdS, enhances the separation efficiency of light-induced electron–hole pairs, and boosts the surface H2-evolution kinetics. This research not only introduces a promising photocatalyst for visible light-driven hydrogen production but also provides a way for the development of highly efficient and stable CdS-based hybrid semiconductor nanocomposites suitable for diverse photocatalytic applications. [ABSTRACT FROM AUTHOR]

The development of high-performance and highly stable electrocatalysts is crucial and challenging for the hydrogen evolution reaction (HER). MOFs complexed with SnS2 can form complexes with inserted structures, and their large specific surface area and numerous pores favor mass transfer, exposing the S active sites to more SnS2, improving the utilisation of the active sites and enhancing the catalytic activity for the HER. Structural collapse can be hindered to improve the stability of the HER composites. Herein, six different kinds of SnS2 were synthesized by a hydrothermal method under discrete conditions, and SI8-SnS2 was screened out to have optimal morphology and electrocatalytic performance. Two innovative SnS2@Ni-MOF and SnS2@HKUST-1 as efficient electrocatalysts were synthesized by a facile grinding method for hydrogen generation. SnS2@Ni-MOF and SnS2@HKUST-1 catalysts showed lower overpotentials of 117 mV and 142 mV at 10 mA cm−2 (η10) and smaller Tafel slopes (58 mV dec−1 and 93 mV dec−1) than six different kinds of SnS2, Ni-MOF and HKUST-1 in 0.5 M H2SO4. Meanwhile, the Cdl values for SnS2@Ni-MOF and SnS2@HKUST-1 were estimated to be 11.5 mF cm−2 and 8.0 mF cm−2, and the stabilities of SnS2, Ni-MOF, HKUST-1, SnS2@Ni-MOF, and SnS2@HKUST-1 were tested at a current density of 10 mA cm−2. The current densities of SnS2@Ni-MOF and SnS2@HKUST-1 were stable over 8 h compared to the pure samples, and SEM, XPS tests were run after the HER test, indicating that the materials have excellent electrocatalytic stability. The syntheses of SnS2@Ni-MOF and SnS2@HKUST-1 enhance their intrinsic catalytic activity, and the porous structure promotes mass transfer efficiency, thereby improving the HER performance, which will guide the development of new and promising electrocatalysts for HER. [ABSTRACT FROM AUTHOR]

Designing cost-effective catalysts with the structural features and necessary functionality to drive ammonia borane hydrolysis for hydrogen generation remains a challenge. In this work, a close heterojunction of Fe3O4--Ni2P uniformly embedded in amorphous carbon material (Fe3O4--Ni2P@C) has been prepared via surface phosphorization. The catalyst displays superior activity with a turnover frequency (TOF) of 92.8 min-1 and favorable durability for ammonia borane hydrolysis, making it superior to most reported nickel-based catalysts. The theoretical studies show a high electron density on the Fe3O4--Ni2P heterojunction. Combining the theoretical and experimental results, the dual active sites at the heterojunction are beneficial to the adsorption of reactant molecules and the reduction of the reaction barrier. This strategy of constructing an appropriate heterojunction to maximize synergistic effects may open a new avenue for non-precious metal catalysis. [ABSTRACT FROM AUTHOR]

Hydrogen gas is a prominent focus in pursuing renewable and clean alternative energy sources. The quest for maximizing hydrogen production yield involves the exploration of an ideal photocatalyst and the development of a simple, cost‐effective technique for its generation. Iron titanate has garnered attention in this context due to its photocatalytic properties, affordability, and non‐toxic nature. Over the years, different synthesis routes, different morphologies, and some modifications of iron titanate have been carried out to improve its photocatalytic performance by enhancing light absorption in the visible region, boosting charge carrier transfer, and decreasing recombination of electrons and holes. The use of iron titanate photocatalyst for hydrogen evolution reaction has seen an upward trend in recent times, and based on available findings, more can be done to improve the performance. This review paper provides a comprehensive overview of the fundamental principles of photocatalysis for hydrogen generation, encompassing the synthesis, morphology, and application of iron titanate‐based photocatalysts. The discussion delves into the limitations of current methodologies and present and future perspectives for advancing iron titanate photocatalysts. By addressing these limitations and contemplating future directions, the aim is to enhance the properties of materials fabricated for photocatalytic water splitting. [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]

The designing of efficient electrocatalysts for hydrogen generation is essential for the practical application of water-splitting devices. With numerous electrochemical advantages, transition metal sulphides are regarded as the most promising candidates for catalysing the hydrogen evolution reaction (HER) in acidic media. In the present study, Ru-doped cobalt sulphide nanosheets, termed Co9S8/Ru@t (t = 24 h, 48 h, and 72 h), were obtained by varying the reaction time from 24 h to 72 h from a RuCo-PBA precursor. The role of the time period for the synthesis of Co9S8/Ru@48h is vital in increasing the number of electroactive sites and optimising the hydrogen adsorption–desorption phenomena leading to an increment in the HER activity. The electrochemical outcomes demonstrate that the optimized Co9S8/Ru@48h requires a low overpotential of just 94 mV to produce 10 mA cm−2 current density, and also exhibits a lower Tafel slope value of 84 mV dec−1 defining its faster reaction kinetics. The as-synthesized Co9S8/Ru@48h was stable for up to 20 h of constant electrolysis signifying its outstanding durability. The optimized synthetic approach and impressive electrochemical results make Co9S8/Ru@48h a suitable alternative to noble-metal-based electrocatalysts for the HER. [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]

Water-splitting coupled with the hydrazine oxidation reaction (HzOR) is a remarkably important strategy for H2 production, but remains a challenge. Herein, a Fe-doped Ni2P-Co2P-Zn3P2 heterogeneous electrocatalyst with a nanoneedle-assembled nanosphere structure and abundant defects was fabricated on Ni foam (Fe-NiCoZnP/NF). The introduction of Fe can tune the electron structure of NiCoZnP/NF, leading to a modulation of the d-band center towards the Fermi level, hence optimizing the free energy of hydrogen (ΔGH*) and dehydrogenation behavior of hydrazine, and thereby realizing splendid HER and HzOR activities. The fabricated Fe-NiCoZnP/NF catalyst displays outstanding HER and HzOR activity and durability, with potentials of 121 and 13 mV vs. RHE to drive 1000 mA cm-2 and Tafel slopes of 31.2 and 11.9 mV dec-1, respectively, and a long durability of 120 h to achieve 100 mA cm-2. Impressively, overall water-hydrazine electrolysis employing Fe-NiCoZnP/NF as the anodic and cathodic electrodes only requires low voltages of 1.92 and 2.67 V to achieve 100 and 1000 mA cm-2, respectively, with a high stability for 120 h operation time during overall hydrazine splitting (OHzS). This work offers a justification for the design of high-efficiency bifunctional catalysts, and promotes energy-saving industry-level hydrogen generation. [ABSTRACT FROM AUTHOR]

The hydrogen production from natural gas has advantages of low investment, low carbon emission, and high hydrogen production rate. This paper briefly describes the technical overview of hydrogen production from natural gas reforming and identifies its risk factors. According to the dangerous characteristics of high reaction temperature, easy leakage of reaction medium, flammability, and explosion in the process, the intrinsic safety of the process is discussed in combination with relevant research and industrial experience. The safety requirements of key equipment and materials are introduced in detail, followed by the optimization methods of process safety that can be taken in the engineering process. Besides, the accident prevention measures for emergency shutdown and fire explosion are summarized. Finally, the future research demands are put forward from the perspective of research and development, which is instructive for the safe hydrogen production from natural gas in the future. [ABSTRACT FROM AUTHOR]