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Ni-doped WC/Mo 2 C composites for hydrogen evolution reaction (HER) were synthesized in situ grown on carbon fiber paper (CFP) by molten salt method in argon at 1000 °C for 6 h, named as Ni-xWC-y/2Mo 2 C@CFP. The effects of different W/Mo molar ratios (3:1, 2:1, 1:1, 1:2, 1:3) on the phase composition, microstructures, and HER performances were investigated. The results showed that the W/Mo molar ratio had a synergistic effect in HER of Ni-doped WC/Mo 2 C composites, and as W/Mo molar ratio at 1:1, the composite presented the best electrocatalytic activity. Meanwhile, its surface appeared to have a wrinkle-like structure, and the biphasic heterostructure emerged at the intersection of the dual-phase WC and Mo 2 C lattices. The introduction of a biphasic heterostructure could promote charge transfer and improve HER efficiency. Predictably, the electrocatalysts with the optimal W/Mo molar ratio 1:1 exhibited the best hydrogen evolution performance, needed only 43.7 mV overpotential to reach 10 mA cm−2 current density with a Tafel slope at 21.3 mV dec−1. In this work, the high-efficiency electrocatalysts of Ni-doped 1WC-1/2Mo 2 C@CFP have been prepared, which provides an insight into theoretical research of composite carbon-based electrocatalysts. [ABSTRACT FROM AUTHOR]

This research investigated the hydrogen production and energy conversion from automobile shredder residues (ASRs) and paper mill sludge (PMS) co-gasified in a full-scale fluidized bed gasification plant. The results obtained from full-scale tests provided important information on the feasible assessment of ASRs-to-energy and the selection of alternative technologies for ASRs. Based on the analysis results of produced gas composition, H 2 , CO, and CH 4 composition produced from paper-mill sludge gasified were 4.17%–6.01%, 3.08%–4.32%, 1.71%–2.4%, respectively. Another C 2 gas composition ranged from 2.9% to 3.59%. The heating value of produced gas ranged between 1.64 MJ/Nm3 and 2.18 MJ/Nm3. In the case of 10% ASR addition, the heating value of produced gas was slightly increased to 1.84 MJ/Nm3-2.34 MJ/Nm3. The dioxin emission concentration of flue gas was approximately 0.064 ng I-TEQ/Nm3. It can comply with Taiwan regulation thresholds. The dioxin leaching concentrations of residues derived from gasification were also in compliance with regulation limits by the TCLP test. Meanwhile, in the case of 10% ASRs addition, the dioxin equivalence concentration of gasified residue was nearly 0.002 ng I-TEQ/Nm3. It was far below the current regulation standard limit. In summary, the results of this research have proved the performance of ASRs-to-energy by co-gasified with paper mill sludge using a full-scale gasification plant. The results obtained from this research also provided the information for selecting ASRs alternative technologies and operating full-scale gasifiers in the future. [Display omitted] • This study has confirmed the feasibility of co-gasification of calcium-rich PMS and chlorine-rich ASRs. • Adding 5%–15% of ASRs can maintain the regular operation of the full-scale commercial gasifier. • The synthesis gas has a composition of 4.91 vol% H 2 and 2.06 vol% CO, with a LHV of 1.93 MJ/Nm3. • The HCl emission could comply with regulation thresholds in co-gasification. • Dioxin reformation reduced significantly in co-gasification of PMS and ASRs. [ABSTRACT FROM AUTHOR]

We herein demonstrate polypyrrole decorated micro-porous laboratory filter paper (PFP) as photoanode (PA) for efficient and stable water splitting. The straddling band position with water redox and the measured band gap of ~1.98 eV, make these PFP-PAs effective for water splitting reactions. The results manifest excellent photo-anodic PEC activity of these PFP-PAs, yielding a photocurrent density of ~9.5 mA/cm2 (at 1.23 V vs. RHE) in a three-electrode configuration. The incident photon-to-current efficiency (IPCE) and applied bias photon-to-current efficiency (ABPE) was measured to be 43.19% and ~1%, respectively. Moreover, the robustness of these flexible PFP-PAs was visualized by the provided stability for more than ~160 min in alkaline conditions. The current study provides a proof-of-concept for the realization of a cost-effective, flexible, and efficient paper-based artificial catalyst (like a natural leaf) for solar-driven water splitting. Image 1 • In-situ fabricated polypyrrole based flexible filter paper photo electrode (PFP-PEs). • Exhibit a bandgap of ~1.98 eV and reported as PEs for water splitting. • Photocurrent density of ~9.5 mA/cm2 (at 1.23 V vs. RHE) in 3-electrode system. • IPCE and ABPE was measured to be 43.19% and ~1%, respectively. • PFP-PEs stable for 160 min in alkaline conditions for PEC water splitting. [ABSTRACT FROM AUTHOR]

Developing flexible gas sensors based on reduced graphene oxide (rGO) are highly promising for practical application, however, it is still challenging due to the sacrificed solution-processibility and mechanical properties after reduction. To address this issue, we here introduce solution-processed rGO and designed a flexible hydrogen (H 2) film sensor by coupling with Pd nanoclusters as the activators via direct colloids mixing and subsequent vacuum filtration. The rGO/Pd nanocluster film features with structural compactness, surface homogeneity, excellent mechanical flexibility, high-efficiency output, and simplification of compositing method. In addition, the film sensor exhibited high response value, fast behavior and stable sensing behavior towards high-concentration H 2 compared with bare rGO film owing to the significant activation role of Pd nanoclusters with ultrasmall sizes (average size: 3.3 nm). Conclusively, this work provides an ingenious and effective way for the design of rGO-based flexible sensor, and shows promise for efficient portable and cost-effective monitoring of environmentally H 2 gases leaks. [ABSTRACT FROM AUTHOR]

Paper and pulp mills generate substantial quantities of cellulose-rich sludge materials that are disposed in landfills at a large scale. For sustainability purposes, sludge materials can be bioprocessed to produce renewable fuels and useful chemicals. The enzymatic hydrolysis of cellulose is the process bottleneck that affects the conversion economics directly by using zero-cost raw materials. In order to study and optimize the process, the characteristics of the sludge raw materials should be first evaluated. In this work, sludge samples were obtained from paper mills located at different locations in Wisconsin and Minnesota. Part of the sludge samples was washed (de-ashed) with hydrochloric acid while the other part remained unwashed. The samples were subjected to multiple spectroscopic analyses techniques to evaluate the morphological properties of cellulose fibers and to estimate the total structural carbohydrate content. The results showed that the de-ashing process changed some fiber characteristics and cellulose crystallinity structure in all sludge samples. Sludge sample A (obtained from Kraft pulp and recycled paper mill region) showed a high percentage of fiber, with crystalline cellulose, compared to the other two sludge samples suggesting that sludge A is a valuable source to make value-added products. Aspen Plus mass and energy calculations performed in view of the 'zero' cost and the reliable supply of sludge raw materials producing 2 mol H 2 /mol glucose. Moreover, the results showed that extracting crystalline cellulose from these sludge samples is more profitable than crystalline cellulose made from the other lignocellulosic feedstocks. The results reported here showed that the utilization of these sludge materials would be an economically attractive and promising alternative for the production of hydrogen. Image 1 • A new method for paper mill sludge (PMS) characterization as renewable feedstock. • The deashing step has a major effect on the bioconversion of the PMS. • Studying the crystalline cellulose of the PMS. • A relation between the characterization and potential sugar yield was established. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-doped 1T-2H MoSe 2 /N doped carbon paper was fabricated by a low-temperature nitrogen plasma strategy. • N doping along with 1T phase into the 2H-MoSe 2 can expose more active edge sites and improve electrical conductivity. • N-MoSe 2 /NCP-30 only needs an overpotential of 274 mV to reach −200 mA cm−2 with Tafel slope of 54.7 mV dec-1. Molybdenum selenide (MoSe 2) is considered to be a promising catalyst for seawater hydrogen evolution, but its catalytic activity falls far short of requirements due to its inert surface. Here, self-supported N-doped 1T@2H-MoSe 2 /N doped carbon paper (N-MoSe 2 /NCP) was fabricated by a novel low-temperature nitrogen plasma strategy. In alkaline simulated seawater, the optimized N-MoSe 2 /NCP-30 only requires an overpotential of 274 mV to reach −200 mA cm−2 with Tafel slope of 54.7 mV dec-1, and exhibits stability over 24 h. This work proposes that the introduction of 1 T phase and N dopant into 2H-MoSe 2 using low-temperature plasma strategy can significantly facilitate the exposure of abundant active edge sites and boost the conductivity of MoSe 2. [ABSTRACT FROM AUTHOR]

Exploring noble-free electrocatalyst for hydrogen evolution by electrolysis of water is significant. Herein, porous Ni(OH) 2 @Ni spherical particles are electrodeposited on carbon papers as efficient electrocatalysts for hydrogen evolution reaction (HER) from water. Due to the porous and composite structure, the HER activity of Ni(OH) 2 @Ni/CP is better than the single phase Ni or Ni(OH) 2 particles on the carbon paper. The overpotential of Ni(OH) 2 @Ni/CP is 106 mV at the current density of 10 mA cm−2 and the Tafel slope is 88 mV dec−1. Moreover, the stability of the catalysts tested for 12 h is also good for HER. Furthermore, the small R ct (1.65 Ω) of Ni(OH) 2 @Ni/CP provides the evident for its excellent catalytic performance. The method of electrodeposition provides the controllable uniform size for porous spherical Ni(OH) 2 @Ni particles. Moreover, the Faradaic efficiency for hydrogen evolution is 100%. Image 1 • The overpotential of Ni(OH) 2 @Ni/CP is 106 mV (10 mA cm−2). • The Tafel slope is 88 mV dec−1 and the stability are good for 12 h. • One-pot preparation of Ni(OH) 2 @Ni/CP via through cyclic voltammetry (CV). [ABSTRACT FROM AUTHOR]

Platinum (Pt)‐based electrocatalysts are the benchmark catalysts for hydrogen evolution reaction (HER); however, they are limited by the scarcity and high price. Introducing an adequate substrate to disperse and anchor Pt‐based species is a feasible pathway to improve the utilization efficiency. Herein, a quick and continuous spray drying route is proposed to fabricate 3D crumpled Ti3C2Tx MXene loaded with sub‐nanometer platinum clusters (Pt/MXene). The 3D crumpled structure inhibits the restacking of layered MXene nanosheets and guarantees the fully exposure of Pt clusters. The as‐prepared catalyst exhibits excellent HER performances comparable to commercial Pt/C, including a low overpotential of 34 mV to reach a current density of 10 mA cm−2, a superior mass activity (1847 mA mgPt−1), a small Tafel slope (29.7 mV dec−1), and a high turnover frequency (10.66 H2 s−1). The improved activity of Pt/MXene can be attributed to the charge transfer from Pt clusters to MXene, which weakens the hydrogen adsorption, as evidenced by the density functional theory calculations. The present contribution proposes a novel strategy to anchor low‐mass‐loading sub‐nanometer precious metal clusters on crumpled MXene with fully exposed active sites for catalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • By slow pyrolysis, pulper waste is converted into a stable, carbon-rich material. • Chemical leaching upgrades the carbon-rich solid to a fossil coal substitute. • The process enables to recover more than 90 % of Ca and Al from pulper waste. • By precipitation, a reusable Al-based flocculating agent is obtained. • Clean hydrogen is produced by the reaction between metallic Al and HCl. This work aims to investigate the potentials of integrating slow pyrolysis and chemical leaching to recycle pulper waste (PW), the waste generated by paper mills, and consists of plastics, metallic films, and biobased polymers. The concentration of chlorine and metals is a barrier against PW valorisation by combustion or high temperature thermochemical processes. In this study, PW was tested by slow pyrolysis at 400 °C and 500 °C. Chemical leaching tests were performed by processing both chars in a 1.4 M HCl solution, at 80 °C for 2 h, to remove inorganic compounds and upgrade the char to a coal-like material. Then, precipitation by NaOH was conducted on the leachate. Slow pyrolysis led to a char mass yield around 30 %. Due to the high inorganic matter concentration (almost 36 %, mainly including chlorine, calcium, and aluminium), the char retained only 25 % of the feedstock's chemical energy, while the remaining 75 % was recovered in the pyrogas. Leaching of the 500 °C pyrolysis char led to extract 93 % of aluminium, and almost 100 % of calcium and chlorine, resulting in an upgraded char containing 15.5 % ash, comparable to a fossil coal. By char leaching, the oxidation reaction of aluminium could produce 8 kg hydrogen per dry ton PW. The effectiveness of the precipitated compounds as flocculating agents was demonstrated, enabling a closed-loop recycling in the same paper mill. In conclusion, the proposed process demonstrated to be an effective solution to convert PW into high quality products. [ABSTRACT FROM AUTHOR]

The development of noble-metal-free electrocatalysts with high electrocatalytic performance and stability by adopting a scalable route is key to solving the energy crisis. We report a P Ni co-doped Mo 2 C-based electrocatalyst with high hydrogen evolution reaction (HER) catalytic activity prepared by a molten-salt method. Using phosphating times of 2 h and 4 h yielded P-Ni-Mo 2 C-2h and P-Ni-Mo 2 C-4h, respectively, both of which exhibited nanoflower-like structures that provided abundant active sites for the reaction. P-Ni-Mo 2 C-2h possessed good electrocatalytic properties with a low overpotential of only 140.5 mV at j = 10 mA cm−2 and a small Tafel slope of 50.7 mV dec−1 in an alkaline environment. P-Ni-Mo 2 C-2h exhibited excellent stability after 20 h of continuous hydrogen production. The use of an excessively long phosphating time caused a narrow down of spaces formed by nanoflakes, thereby reducing the HER performance of the electrocatalyst. The results of this study provide guidelines for the preparation of high-efficiency P Ni co-doped electrocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

A two-stage thermophilic hydrogen fermentation and mesophilic methane production from paper sludge was successfully explored. The maximum hydrogen and methane potential were 0.165 L/g VS and 0.376 L/g COD effluent , respectively with Clostridium thermocellum augmentation. 63 L of hydrogen and 122 L of methane were recovered from 1 kg Paper sludge (PS, dry weight) with an energy yield of 4.5 MJ/kg PS, 50% higher compared to the single-stage anaerobic digestion (94 L CH 4 , 3.0 MJ/kg PS). The bacterial community of second-stage process was dominated by genus Propionispira , Mesotoga and Aminobecterium with stability, whereas the bacterial structure in single-stage process presented dynamic changes where genus Acetivibrio and Fibrobacter played an indispensable role. However, Genus Methanosaeta , Methanosarcina , Methanobacterium and Methanospirillum existed stably and predominantly in the archaeal community of single-stage and second-stage processes. The present study suggests the potential application of the established two-stage process in valorization of low-value waste biomass. Image 1 • C. thermocellum enhanced two-stage H 2 and CH 4 production from PS was established. • 50% more energy recovery was achieved from two-stage than single-stage. • Archaeal community structure of two BMP tests showed no difference. [ABSTRACT FROM AUTHOR]

• Solid fermentation of paper was successful in lysimeters at 35 and 55 °C. • Homoacetogenesis was prominent under mesophilic conditions. • Alcohol production, ethanol and methanol, was favored under thermophilic conditions. • Dysgonomonas and Ruminococcus were the most abundant populations at 35 °C. • Thermicanus was the main population at a thermophilic temperature of 55 °C. This study explored the hydrolysis and fermentation of paper with hydrogen (H 2) and volatile fatty acid (VFA) recovery using a natural microbial consortium added to lysimeters. Serial dilutions of rumen fluid in natura were performed to obtain a fermentative nonmethanogen consortium, which was used as inoculum in lysimeters under two different incubation temperatures, L1 at 35 °C and L2 at 55 °C. H 2 was detected in both lysimeters: 791.5 mL (L1) and 70.4 mL (L2). In L1, the production of 16,856 mg L−1 acetic acid was likely due to the occurrence of homoacetogenesis. Under thermophilic conditions, L2, a low volume of H 2 was detected, and the highlight was the production of ethanol and methanol at 2289 and 5614 mg L−1, respectively. According to the Shannon index, there was great diversity of microorganism populations in the rumen fluid in natura (6.34) compared with the purified rumen fluid (2.73), L1 (2.67) and L2 (3.21). The most abundant genus in the rumen fluid in natura was Prevotella (37.5 %); in the purified consortium (68.7 %) and L1 (63.8), Dysgonomonas ; and in L2 (88.7 %), Thermicanus. In conclusion, the temperature influenced the microbial community structure, the metabolic route and, consequently, the main byproducts produced by the fermentative activity at 35 °C and 55 °C. [ABSTRACT FROM AUTHOR]

The anomalous heat effect reported in the paper, "Excess heat evolution from nanocomposite samples under exposure to hydrogen isotope gases" by Kitamura et al. published in the Int. J. Hydrogen Energy 43 , pp. 16,187–16,200 (2018), is investigated in the science of the cold fusion phenomenon (CFP) established in these 30 years. It is concluded that the effect is a normal event in the CFP consistent with many events observed in materials with various components and compositions composed of host elements and hydrogen isotopes. • Cold fusion phenomenon means the nuclear reactions in solids with hydrogen isotopes. • Nuclear reactions occur in solids without any acceleration mechanism. • Excess energy accompanied to the nuclear reaction is useful for an energy source. [ABSTRACT FROM AUTHOR]

Pulp and paper mill effluent (PPME), a rich cellulosic material, was found to have great potential for biohydrogen production through a photofermentation process. However, pretreatments were needed for degrading the complex structure of PPME before biohydrogen production. The aim of this study was to gain further insight into the effect of an ultrasonication process on PPME as a pretreatment method and on photofermentative biohydrogen production using Rhodobacter sphaeroides NCIMB. The ultrasonication amplitudes and times were varied between 30–90% and 15–60 min, respectively, and no dilution or nutrient supplementation was introduced during the biohydrogen production process. A higher biohydrogen yield, rate, light efficiency and COD removal efficiency were attained in conditions using ultrasonicated PPME. Among these different pretreatment conditions, PPME with ultrasonication pretreatment employing an amplitude of 60% and time of 45 min (A60:T45) gave the highest yield and rate of 5.77 mL H 2 /mL medium and 0.077 mL H 2 /mL h, respectively, while the raw PPME without ultrasonication showed a significantly lower yield and rate of 1.10 mL H 2 /mL medium and 0.015 mL H 2 /mL h, respectively. The results of this study demonstrated the potential of using ultrasonication as a pretreatment for PPME because the yield and rate of biohydrogen production were highly enhanced compared to the raw PPME. Economic analysis was also performed in this study, and in comparison with raw PPME, the highest net saving was $0.2132 for A60:T45. [ABSTRACT FROM AUTHOR]

Hydrogen fuel is a non-toxic and source-abundant energetic system, but for its applications in the industry, several issues related to its storage must be resolved. Compounds like NaBH 4 appear as promising hydrogen sources, while can release the latter rapidly under controllable conditions with the use of heterogeneous catalyst systems. In this work, we synthesized a Ni–CoP catalyst by electrodeposition in a three-step process on carbon paper as support. The materials were characterized via SEM-EDS, XRD, and XPS techniques, while the hydrogen evolution reaction (HER) from alkaline NaBH 4 solutions was tested as a batch experiment. Ni–CoP catalyst showed a high amount of H 2 generated in a short time (∼550 mL in 1 min) and remained at 78 and 54% of its initial performance after respectively 100 and 300 h of a continuous hydrolysis process. Our catalyst revealed exceptional performance and stability at higher temperatures and a long process time, which have been a rare subject of investigation in other reports for NaBH 4 hydrolysis in the past. This work paves a new perspective in studying catalysts for hydrogen generation from borohydrides. [Display omitted] • Ni–CoP catalyst was electrodeposited on a carbon support. • Material characterization proved the formation of desired active layers. • High efficiency and stability of the catalyst for a long-term NaBH 4 hydrolysis was revealed. [ABSTRACT FROM AUTHOR]

The escalating demand for renewable energy solutions and the imperative for efficient energy storage mechanisms have catalyzed the evolution of Power-to-X (PtX) technologies. Germany has the most PtX projects, accounting for 44% of all projects that have been reported. PtX encompasses a spectrum of processes engineered to convert surplus renewable energy into versatile energy carriers or chemical commodities, such as hydrogen, methane, or synthetic fuels. The Paramount to this domain is to synergistically harness renewable energy sources and hydrogen carriers to curtail waste and bolster sustainability. Central to achieving this synergy is the effective control of PtX processes, ensuring optimal performance, cost efficiency, and seamless integration within existing energy frameworks. This paper delves into the control processes and environmental prerequisites within the PtX landscape, elucidating key challenges, and strategies within this dynamic realm. While providing an initial overview of fundamental PtX process chains, this paper accentuates the critical role of geographical considerations. Subsequently, it conducts a thorough analysis of equipment modeling challenges, addressing performance metrics, operational requisites, and capital investments, particularly focusing on methanol and hydrogen production and storage. Through holistic examination, this paper endeavors to delineate the evolving landscape of PtX control processes and conditions, advancing our understanding of this expanding field. [Display omitted] • Comprehensive overview of PtX control process, challenges, strategies, and advancements. • Overview of PtX process chains and geographical conditions. • Analysis of equipment modeling challenges for methanol and hydrogen. • Addressing crucial storage challenges in PtX system. • Exploration of diverse influences on PtX control processes. [ABSTRACT FROM AUTHOR]

Stationary hydrogen energy-based power plants generating electricity to supply high-powered plug-in electric vehicles (PEVs) have recently become popular in renewable energy-based power plants. Besides, in a PEV charging station, various types of powered charge devices can be established such as DC fast chargers or 3.7 kW, 7.4 kW, 11 kW, and 22 kW AC chargers. This paper introduces a demand-side management-oriented optimal charging strategy that includes two stages for PEVs in a hydrogen energy-based microgrid. The paper focuses on two stages to execute an optimal charging of PEVs in compliance with their users' requests and satisfaction and considering the power system loading. It is assumed that there are three types of chargers in the PEV charging station and the users. In the first stage randomly created requests are classified by an ensemble learning classifier method that performs higher performance classification by combining the results from multiple classifiers in a machine learning classification. The second stage schedules the PEVs according to the classification results and users' requests. To test the proposed system, first random requests are created then they are sent to the classifier, and the results of classifiers are scheduled in each other. The demand-side management-oriented charge scheduling and managing strategy which includes the proposed two stages has been compared with non-managed cases. Case study results reveal that the proposed approach provides 52.1% peak load reduction and 72.3% valley filling improvement by the SOS algorithm. The results highlight the advantages of the proposed system in terms of peak reduction and valley filling. [Display omitted] • A new intelligent decision-maker method is proposed for DSM in a microgrid. • Proposed method is developed for a stationary hydrogen energy-based power plant. • The optimal DSM of EVs is investigated with a hybrid ML method. • RUSBoost and SOS Algorithms-based Hybrid Intelligent Decision Maker is developed. • It provides 52.1% peak load reduction and 72.3% valley filling improvement. [ABSTRACT FROM AUTHOR]

Hydrogen is an ideal energy source and plays an important role in increasingly global energy issues and environmental problems. Liquid hydrogen (LH2) has many advantages over other storage methods, especially in terms of energy density. However, it may cause enormous harm once it leaks accidently. LH2 leakage is a complex multiphase process involving evaporation, condensation, transfer of mass and heat, and dispersion. In order to study LH2 transportation and storage systems safety, a research project has been carried out to develop a 3D numerical model using an open-source CFD code, OpenFoam, for investigating LH2 accidental release scenarios. Since the release of LH2 is a very complex process, our strategy is to study it step by step. Therefore, in this paper we present our research work at the first stage, a dispersion process of room-temperature gaseous hydrogen without multiphase flow. A small-scale hydrogen release conducted by Sandia National Laboratories is simulated. In this experiment, room-temperature gaseous hydrogen is injected upwards into the air from a small hole with a 1.91 mm diameter. The situations of Froude (Fr) number = 99, 152, and 268 are studied, respectively. The behavior of hydrogen at different Fr numbers is discussed. When high-speed hydrogen enters the air, the speed and concentration of hydrogen decrease rapidly. In addition, the greater the speed, the faster it decays. The result shows a close range of hydrogen reach. Details about the numerical model are introduced. The simulation results are used to verify the validity of the developing numerical model for dispersion and mixing of multi-species. The simulated concentrations and velocity distribution are analyzed and compared with experimental data. The simulation shows a good agreement with the data of Sandia National Laboratories. The agreement between experiments and simulations is measured using the Pearson correlation coefficient (>0.98), which indicates excellent consistency. In the next step, we will integrate the multiphase flow and phase change into the current model. The phase change of liquid hydrogen and air will be simulated to study the release of liquid hydrogen. • Using the open-source CFD code OpenFOAM for simulation of hydrogen jet. • A good agreement between the simulations results and experimental data has been found in this paper. • When high-speed hydrogen is injected into the air, both velocity and concentration drop rapidly. • Final concentration is not sensitive to different injection velocity. [ABSTRACT FROM AUTHOR]

This paper explores a novel method of focuses on utilizing ammonia as a hydrogen carrier that can be decomposed to produce hydrogen, the combustion of which produces steam for generating power in turbines. The simulation for such a process is performed on ASPEN Plus software. The key steps include compressing the ammonia and passing it through a fluidized bed reactor (FBR) for its decomposition, subsequently compressing the products before combusting the hydrogen with compressed air in a combustor and extracting power from the hot products through a series of turbines. The article examines in detail the effect of different parameters on the performance of the individual components as well as the overall process. Specifically, considerable emphasis is placed on the effects of varying pressures and temperatures on the functioning of the FBR at different catalyst loadings, their effects on the combustor performance and the dependence of the overall process on the air flowrate in the combustor. The comprehensive analysis elucidated on the energy efficiency of the process and it identified conditions at 2 bar pressure and 550 °C temperature as being the most favorable for ammonia decomposition and subsequent turbine power output while lean hydrogen combustion with excess air making the inlet hydrogen concentration less than 20% resulted in optimum temperatures at the turbine inlet. • The paper explores ammonia as a hydrogen carrier in the power plant industry through ASPEN PLUS process simulations. • The initial step is to decompose ammonia into nitrogen and hydrogen in a fluidized bed reactor, the optimum operating condition of which turns out to be 2 bar pressure and 550 °C. • The next steps involve mixing air with the decomposition products, pressurizing them to 40-60 bar, combusting hydrogen in a plug flow reactor to produce steam and finally expanding it in a series of turbines to generate power. • Detailed flow and more importantly, energy analysis of all the process units show ammonia as a very effective hydrogen carrier for applications in power plants. [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]

Development of a hydrogen economy as part of the response to the challenges especially of climate change and energy security will depend upon the solution not only of technical problems, but also of legal and regulatory problems. Whereas these are most obviously related to health and safety, this paper focuses on the fact that support for hydrogen is increasingly contingent upon the method of its production and specifically upon the level of greenhouse gas emissions involved. The paper examines emerging arrangements in Australia and the EU as examples of likely future key hydrogen exporters and importers, respectively. [ABSTRACT FROM AUTHOR]

The power system using hydrogen fuel cells (FCs) as the primary energy source holds significant potential for applications in emergency fields such as post-disaster relief and outdoor power supply. The operational environment of the FC emergency power supply system (FCEPSS) is challenging, with long continuous operation time, difficulties in hydrogen supply, high maintenance costs, and, accordingly, requirements for hydrogen consumption and useful life of FCs are heightened. Hence, this paper proposes a multi-objective energy management strategy (EMS) for FCEPSS. First, the structure of FCEPSS is designed based on the demand analysis in emergency scenarios. Then, the hydrogen consumption and life degradation models of FCEPSS are established. Aiming at the multi-objective optimization problem of minimizing hydrogen consumption and life degradation value in the FCEPSS, an improved multi-objective optimization algorithm is proposed. This paper converts complex constraints into the penalty term and incorporates it as one of the objectives, constructing a three-objective optimization model. To enhance the solution of multi-objective optimization problems, an improved strategy based on relaxation-tightening and three-objective sorting is proposed. Combining the fast non-dominated sorting genetic algorithm-II and the above improved strategy, an improved multi-objective optimization algorithm (IMOOA) is constructed. In the simulation, the advantages of the proposed IMOOA algorithm are verified. In the experimental part, compared with the logical threshold strategy, the proposed strategy saves 0.60% of hydrogen consumption and reduces 5.65% of life degradation within 24 h, respectively. Finally, the superiority of the multi-objective EMS utilizing the IMOOA is demonstrated. [Display omitted] • The demand analysis and scheme design of fuel cell emergency power supply system are carried out. • A multi-objective energy management strategy for low hydrogen consumption and long useful life is designed. • An algorithm based on the relaxation-tightening and three-sorting principle is constructed. [ABSTRACT FROM AUTHOR]

A green hydrogen (H 2) economy requires a sustainable, efficient, safe, and widespread infrastructure for transporting and distributing H 2 from production to consumption sites. Transporting a hydrogen/natural gas (H2NG) mixture, including pure H 2 , through the existing European natural gas (NG) infrastructure is considered a cost-effective solution, particularly in the transitional phase. Several reasons justify the H2NG blending option. The NG infrastructure can be efficiently repurposed to transport H 2 , by blending H 2 with NG, to operate as H 2 daily storage, matching production and demand and to enable large-scale seasonal H 2 storage. Although many benefits exist, the potential of existing NG grids for transporting and distributing green H 2 may face limitations due to technical, economic, or normative concerns. This paper focuses on the state of the art of the European NG transmission and distribution metrology normative framework and identifies the gaps to be filled in case of H2NG flowing into the existing grids. The paper was revised to provide a comprehensive analysis of the practical implications resulting from the H2NG blend option. [Display omitted] • The RePowerEU planned hydrogen production and utilization to achieve decarbonization targets. • The existing gas grid is considered for transporting and distribute large hydrogen amounts. • The European Committee for Standardization defined Standards on gas grid instrumentation. • A review of the European natural gas grid metrology normative was carried out in THOTH2 Project. • Standards need to be revised to account for hydrogen-natural gas mixtures transportation. [ABSTRACT FROM AUTHOR]

Gassing problems and premature insulation failures in wind turbine transformers indicate reliability concerns about the insulation of such components. This fact necessitates investigating degradation of transformer insulation systems under high-dV/dt pulse voltages that exist in today's wind energy plants. For this purpose, PD activity, generally assumed to be the main long-term cause of insulation deterioration, needs to be analyzed. This work evaluates the effects of impulse voltage parameters such as rate of rise and repetition frequency on inception voltage and intensity of PD activities. PD parameter measurement under high-dV/dt voltages is challenging due to interferences from fast oscillations, and difficulties of PD energy measurements. To avoid such issues, which are related to electromagnetic detection methods under pulse energization, this work uses a chemical approach to compare PD activities, based on the rate of hydrogen generation in a controlled test chamber with oil/paper samples. Gas monitoring of the oil containing impregnated paper samples reveals that a faster rate of rise increases PD energy as well as inception voltage. Results based on experiments conducted in small oil chambers show good correlation between the amount of hydrogen detected and PD energy level; hence it can be used as a benchmark for comparing PD energy levels under various impulse waveforms. [ABSTRACT FROM AUTHOR]

Pulp and paper industry primary sludge being largely composed of lignocellulosic fibres, it could be used as carbon source by bacteria having cellulolytic capability. The aim of this study was to evaluate the use of cellulose contained in this type of sludge for Clostridium thermocellum to produce ethanol, hydrogen and cellulases. In an ATCC 1191 medium containing 5 kg m −3 dry primary sludge from recycled paper mill, batch culture reached stationary phase after 2 days. All of the available cellulose was hydrolysed after 60 h of incubation, with a final pH of 5.83. Metabolites produced after 60 h of fermentation were acetate (8.50 mol m −3 ), ethanol (11.30 mol m −3 ), lactate (8.75 mol m −3 ), formate (0.27 mol m −3 ), hydrogen (11.20 mol m −3 ) and carbon dioxide (18.41 mol m −3 ). Cellulase activity was detected in the supernatant after 36 h, with a maximal activity of 0.25 U cm −3 at 72 h. Pulp and paper primary sludge appeared to be a readily usable substrate for C. thermocellum at this concentration, yielding both potential biofuels (hydrogen and ethanol) as well as active cellulases. [ABSTRACT FROM AUTHOR]

Carbon-based single-atom catalysts, a promising candidate in electrocatalysis, offer insights into electron-donating effects of metal center on adjacent atoms. Herein, we present a practical strategy to rationally design a model catalyst with a single zinc (Zn) atom coordinated with nitrogen and sulfur atoms in a multilevel carbon matrix. The Zn site exhibits an atomic interface configuration of ZnN4S1, where Zn's electron injection effect enables thermal-neutral hydrogen adsorption on neighboring atoms, pushing the activity boundaries of carbon electrocatalysts toward electrochemical hydrogen evolution to an unprecedented level. Experimental and theoretical analyses confirm the low-barrier Volmer-Tafel mechanism of proton reduction, while the multishell hollow structures facilitate the hydrogen evolution even at high current intensities. This work provides insights for understanding the actual active species during hydrogen evolution reaction and paves the way for designing high-performance electrocatalysts. [ABSTRACT FROM AUTHOR]

Biological hydrogen production from the anaerobic fermentation of ultrasonic-pretreated paper mill sludge started at a pH of 5.5 and a temperature of 36.5°C. When the sludge reaction time (SRT) was 32 h, the organic loading rate (OLR) was 3,000 mg chennai oxygen demand (COD)·L-1·d-1, and the hydrogen production yield was 620.8 mL H2/g COD. The Gompertz equation was used for regression analysis of accumulated hydrogen yield, which indicated that R2 was 0.99. Hydrogen was produced by typical ethanol-type fermentation and the utilization of organic material was 31.8%. [ABSTRACT FROM AUTHOR]

In order to improve the hydrogen sensing of transition metal oxide nanomaterials at room temperature, MoO 3 nanowire paper was prepared and used as a hydrogen sensing materials on substrate. In this paper, orthorhombic phase, ultra-long (∼1 mm) MoO 3 nanowires were synthesized through conventional hydrothermal method at 260 °C for 96 h. A flexible nanowires paper with size of 200 mm × 300 mm was obtained by further self-assembly formation process of pure α-MoO 3 nanowires in aqueous solution on hydrophobic substrate, and the thickness of paper can be controlled depend on the concentration of disperse nanowires. A novel hydrogen sensor with sensing area of 10 mm × 10 mm was obtained after Pt interdigital electrodes (IDE) deposited on the surface of α-MoO 3 nanowires paper and transferred into ceramic circuit board (CCB) without any surface modification. The response and recovery time are about 3.0 and 2.7 s toward 1.5% H 2 , respectively. The sensors also show good selectivity toward H 2 against other reduce gas, such as C 2 H 5 OH, CO and CH 4 . Large amounts of the porous structures and high specific surface of nanowires paper is beneficial to the absorption of oxygen molecules, which would lead to the high sensitivity, fast response and recovery speed of sensor at room temperature. MoO 3 nanowires paper sensors have excellent stability and reliability, which could work for 5.56 years at room temperature. [ABSTRACT FROM AUTHOR]

In order to meet rapidly growing demand of liquid hydrogen in the future hydrogen industry and energy structure, the continuous catalytic ortho-para hydrogen conversion technology (CCOPHCT) has been once again proposed and has become an important choice to improve the hydrogen liquefaction units (HLUs). The origin, concept, and research progress of the CCOPHCT are systematically reviewed for the first time in this paper. However, the research depth and breadth of the CCOPHCT are insufficient to support its current application. To solve it, for the continuous catalytic ortho-para hydrogen conversion plate-fin heat exchanger (CCOPHC-PFHE) with better comprehensive performances, this paper comprehensively summarizes the research achievements in the related fields from the perspective of the unit analysis, including the ortho-para hydrogen conversion (OPHC), packing layer and plate-fin heat exchanger (PFHE), which to provide further thinking for the development of the CCOPHC-PFHE. Further, some suggestions for the CCOPHCT are proposed based on the existed research foundations, including preparing the effective ortho-para hydrogen conversion catalyst (OPHCC), developing the accurate OPHC dynamical model, revealing the coupling mechanism in the packing layer filled with the OPHCC and establishing an effective design method and standard of the CCOPHC-PFHE. In addition, considering the special conditions on the CCOPHC-PFHE, the importance of the experimental research is emphasized. And based on the established hydrogen experimental platform with the comprehensive supporting implementations, the experimental device of the CCOPHC-PFHE has been completed and a series of experimental tests are currently in progressing. [Display omitted] • The origin, concept, and progress of the CCOPHCT are reviewed for the first time. • The CCOPHC-PFHE is the preferred choice for the CCOPHCT. • The related researches are summarized to give a further thinking for the CCOPHC-PFHE. • Some suggestions are proposed for the further development of the CCOPHC-PFHE. • The experiment on the CCOPHC-PFHE is essential and currently in progressing. [ABSTRACT FROM AUTHOR]

This paper delves into the critical role of tax credits, specifically Sections 45Q and 45V, in the financing and economic feasibility of low-carbon-intensity hydrogen projects, with a focus on natural-gas-based hydrogen production plants integrated with carbon capture and storage (CCS). This study covers the current clean energy landscape, underscoring the importance of low-carbon hydrogen as a key component in the transition to a sustainable energy future, and then explicates the mechanics of the 45Q and 45V tax credits, illustrating their direct impact on enhancing the economic attractiveness of such projects through a detailed net present value (NPV) model analysis. Our analysis reveals that the application of 45Q and 45V tax credits significantly reduces the levelized cost of hydrogen production, with scenarios indicating a reduction in cost ranging from USD 0.41/kg to USD 0.81/kg of hydrogen. Specifically, the 45Q tax credit demonstrates a slightly more advantageous impact on reducing costs compared to the 45V tax credit, underpinning the critical role of these fiscal measures in enhancing project returns and feasibility. Furthermore, this paper addresses the inherent limitations of utilizing tax credits, primarily the challenge posed by the mismatch between the scale of tax credits and the tax liability of the project developers. The concept and role of tax equity investments are discussed in response to this challenge. These findings contribute to the broader dialogue on the financing of sustainable energy projects, providing valuable insights for policymakers, investors, and developers in the hydrogen energy sector. By quantifying the economic benefits of tax credits and elucidating the role of tax equity investments, our research supports informed decision-making and strategic planning in the pursuit of a sustainable energy future. [ABSTRACT FROM AUTHOR]

Hydrogen-powered mobility is believed to be crucial in the future, as hydrogen constitutes a promising solution to make up for the non-programmable character of the renewable energy sources. In this context, the hydrogen-fueled internal combustion engine represents one of the suitable technical solutions for the future of sustainable mobility. As a matter of fact, hydrogen engines suffer from limitations in volumetric efficiency due to the very low density of the fuel. Consequently, hydrogen-fueled ICEs can reach sufficient torque and power density only if suitable supercharging solutions are developed. Moreover, gaseous-engine performance can be improved to a great extent if direct injection is applied. In this perspective, a remarkable know-how has been developed in the last two decades on NG engines, which can be successfully exploited in this context. The objective of this paper is twofold. In the first part, a feasibility study has been carried out with reference to a typical 2000cc SI engine by means of 1D simulations. This study was aimed at characterizing the performance on the full load curve with respect to a baseline PFI engine fueled by NG. In this phase, the turbocharging/supercharging device has not been included in the model in order to quantify the attainable benefits in the absence of any limitation coming from the turbocharger. In the second part of this paper, the conversion of a prototype 1400cc direct injection NG engine, running with stoichiometric mixture, to run on a lean hydrogen combustion mode has been investigated via 1D simulations. The matching between engine and turbocharger has been included in the model, and the effects of two different turbomatching choices have been presented and discussed. [ABSTRACT FROM AUTHOR]

Low or even zero carbon dioxide emissions will be an essential requirement for energy supplies in the near future. Besides transport and electricity generation, industry is another large carbon emitter. Hydrogen produced by renewable energy provides a flexible way of utilizing that energy. Hydrogen, as an energy carrier, could be stored in a large capacity compared to electricity. In Sweden, hydrogen will be used to replace coal for steel production. This paper discusses how the need for electricity to produce hydrogen will affect the electricity supply and power flow in the Swedish power grid, and whether it will result in increased emissions in other regions. Data of the Swedish system will be used to study the feasibility of implementing the hydrogen system from the power system viewpoint, and discuss the electricity price and emission issues caused by the hydrogen production in different scenarios. This paper concludes that the Swedish power grid is feasible for accommodating the additional electricity capacity requirement of producing green hydrogen for the steel industry. The obtained results could be references for decision makers, investors, and power system operators. [ABSTRACT FROM AUTHOR]

Locomotive engines serve as the powering heart of rail transportation which is widely used for massive cargo over long distances. The traditional locomotive engines have depended on the internal combustion engine for decades, operated using fossil fuels that negatively impact the environment. Since more and more commodities are transported by trains, the prime engines need to be improved where the fuels are expected to enhance the engine's performance and alleviate the environmental impact. This paper presents a comparison of three developed locomotive engines with different configurations, such as an internal combustion engine combined with a gas turbine and molten carbonate fuel cell (ICE-GT-MCFC), a gas turbine combined with a solid oxide fuel cell and onboard hydrogen production using aluminum electrolysis cell (GT-SOFC), and a GT combined with sold oxide and proton exchange membrane fuel cells (GT–SOFC–PEMFC). The paper then identifies one hybridized engine, which is GT–SOFC–PEMFC, according to its low weight and better performance to conduct an optimization study to enhance its efficiency, reduce the cost, and lower the environmental impact. The present optimization study is undertaken through a multi-objective particle swarm optimization, involving thermodynamic, exergoeconomic, and exergoenvironmental analyses. The optimized GT–SOFC–PEMFC locomotive engine is improved in power from 5.9 MW to 7.3 MW and improved in performance to 49.1% energetic efficiency and 47.0% exergetic efficiency. Additionally, the optimized GT–SOFC–PEMFC engine has less specific fuel and product cost of 24.9 $/GJ and 34.7 $/GJ, respectively, and less specific exergetic environmental impact of fuel and product of 13.2 Pt/GJ and 16.2 Pt/GJ, respectively. Also, the relative cost difference and relative environmental impact difference are significantly reduced by more than 20% to 39.4% and 22.8%, respectively. The operational conditions of the optimized GT–SOFC–PEMFC engine are improved to achieve better efficiency and better cost effectiveness in a more environmentally-benign manner. • Comparison between three hybridized combined locomotive engines is established. • Optimized GT–SOFC–PEMFC engine has 7.3 MW power and 49% energetic efficiency. • Specific exergetic product cost declined to 51 $/GJ for fuel and 35 $/GJ. • Specific exergetic environmental impact for fuel and product becomes 13 and 16 Pt/GJ. • The relative environmental impact difference becomes 22.8% instead of 44.3%. [ABSTRACT FROM AUTHOR]

The paper presents an investigation of the performance of the proton exchange membrane (PEM) electrolyser directly connected with large-scale PV systems under faulty, degradation and partial shading conditions. With the direct coupled system, the power loss and external price on auxiliary devices are avoided. However, the adaptability of the direct coupled system to fluctuate solar irradiance and ambient temperature is reduced significantly compared to systems with DC-DC converters. To maximise the system efficiency, the optimal electrolyser (ELY) cell configuration is identified using an optimal sizing approach or operating strategy. This paper applied the Particle Swarm Optimisation (PSO) algorithm to find the optimal configuration for the two approaches, namely the Sizing technique and Operating strategy under different PV systems: faults, degradation and partial shading conditions. Additionally, a large-scale system is simulated to describe the characteristics of a large-scale direct coupled PV-electrolyser system with actual operating faults and phenomena. Simulations of the large-scale direct coupling system were conducted using measured irradiance and temperature data for a typical day period. Based on the collected output, it is found that compared to the optimal sizing approach, the optimal operating strategy allows the direct coupled system to increase its coupling efficiency from 0.17% to 4.47%. In contrast, the amount of hydrogen production when applying the two methods witnessed different trends, depending on the type of faults. The differences are even more significantly presented during multiple short-circuit fault scenarios. • Modelling of a large-scale direct coupling PV-electrolyser system up to 1 MW. • An analysis of typical PV system faults, partial shading, and degradation phenomenon. • A comparison of the optimal sizing approach and operating strategy. • Proposed optimal operating strategy allows 99.99% coupling factor in normal operation. [ABSTRACT FROM AUTHOR]

In pursuit of energy transition objectives, Algeria is increasingly focusing on the production and utilization of low-carbon and renewable hydrogen. While hydrogen has predominantly been used in the chemical and refining industries, it holds promise for decarbonizing specific industrial sectors, enabling electricity storage, and powering the transport sector. However, several barriers must be overcome before hydrogen technologies can be widely deployed. Numerous countries, with Japan at the forefront, are heavily investing in this burgeoning market, anticipating the creation of thousands of new jobs. Hydrogen offers Algeria significant potential for greenhouse gas (GHG) reduction and substantial economic benefits. In response, the Algerian government has prioritized energy transition to new and renewable sources as part of its economic recovery plan, aiming for "green" growth through innovative and digital energy technologies. This paper's primary objective is to provide a techno-economic foundation for guiding public policy development, identifying promising opportunities for green hydrogen within Algeria's energy transition context, and outlining sustainable pathways for pilot projects that promote hydrogen adoption within the Algerian society. Additionally, this paper will explore the latest advancements in hydrogen research, technology, and applications relevant to the Algeria's energy transition. The Algerian energy minister, has reaffirmed his desire to "invest in hydrogen", an energy source presented as one of the solutions to the climate crisis. In October 2021, Algeria launched a hydrogen plan worth several billion dinars, including 100 million for research, to enable the country to develop "green" hydrogen, i.e. produced without fossil fuels. • Algeria's energy transition mission focuses on promoting energy transition, innovation, and efficiency. • The Algerian Strategy on Green Hydrogen 2050 intends to establish a supportive framework for hydrogen sector development. • Algeria has set ambitious targets: reducing its GHG emissions by 2030 and lowering its consumption of petroleum products. • Algeria export between 30 and 40 TWh by 2040 of gaseous green hydrogen, liquefied, and derived. [ABSTRACT FROM AUTHOR]

The present paper offers a thorough examination of the safety measures enforced at hydrogen filling stations, emphasizing their crucial significance in the wider endeavor to advocate for hydrogen as a sustainable and reliable substitute for conventional fuels. The analysis reveals a wide range of crucial safety aspects in hydrogen refueling stations, including regulated hydrogen dispensing, leak detection, accurate hydrogen flow measurement, emergency shutdown systems, fire-suppression mechanisms, hydrogen distribution and pressure management, and appropriate hydrogen storage and cooling for secure refueling operations. The paper therefore explores several aspects, including the sophisticated architecture of hydrogen dispensers, reliable leak-detection systems, emergency shut-off mechanisms, and the implementation of fire-suppression tactics. Furthermore, it emphasizes that the safety and effectiveness of hydrogen filling stations are closely connected to the accuracy in the creation and upkeep of hydrogen dispensers. It highlights the need for materials and systems that can endure severe circumstances of elevated pressure and temperature while maintaining safety. The use of sophisticated leak-detection technology is crucial for rapidly detecting and reducing possible threats, therefore improving the overall safety of these facilities. Moreover, the research elucidates the complexities of emergency shut-off systems and fire-suppression tactics. These components are crucial not just for promptly managing hazards, but also for maintaining the station's structural soundness in unanticipated circumstances. In addition, the study provides observations about recent technical progress in the industry. These advances effectively tackle current safety obstacles and provide the foundation for future breakthroughs in hydrogen fueling infrastructure. The integration of cutting-edge technology and materials, together with the development of upgraded safety measures, suggests a positive trajectory towards improved efficiency, dependability, and safety in hydrogen refueling stations. [ABSTRACT FROM AUTHOR]

Current U.S. government policy seeks to achieve a completely carbon-free economy by 2050, with a carbon-free electricity sector by 2035 (per executive orders #14008 and #14057). To address these goals, the U.S. Department of Energy is evaluating strategies and technologies that support the production, utilization, transport, and storage of hydrogen (via initiatives such as Department of Energy's (DOE) Energy Earthshot--Hydrogen and various DOE funding opportunity announcements). A carbon-free fuel such as hydrogen cannot be overvalued in a dynamic electric energy sector seeking to decarbonize. One of the most important technologies needed to achieve the goal of a carbon-free electricity sector is a 100% hydrogen-fueled gas turbine. Accommodating hydrogen-based fuels has been a key goal for various original engine manufacturers (OEMs) for many years, but much more research and development (R&D) is needed. The purpose of this paper is to highlight the current state-of-the-art of hydrogen turbine technology, especially regarding nitrogen oxide (NOX) emissions compared to natural gas-fueled turbines. NOX is the primary criteria pollutant from thermally driven combustion turbines and should be controlled to levels that are equivalent to or below existing standards (as reported "existing standards" for hydrogen-fueled gas turbines may need to be rebaselined). This paper will provide an overview of hydrogen as a fuel and various NOX emissions control techniques that are relevant for hydrogen-based fuels. A conclusion from this overview is that, with some level of R&D, NOX emissions from hydrogen-fueled gas turbines can be controlled to levels similar to those produced by state-of-the-art (SOTA) natural gas-fueled combustion turbines while remaining competitive in terms of performance and efficiency. [ABSTRACT FROM AUTHOR]

This paper precisely estimates the looming demand for hydrogen within the transportation sector, spanning 14 pivotal G20 nations from 2022 to 2050, anchored in the global vehicle hydrogen market penetration rate. Employing a robust techno-economic modeling methodology and leveraging Geographic Information System (GIS) for enriched visualization, it unveils distinct environmental dividends across three thoughtfully devised scenarios: Business- as -Usual, Moderate, and Aggressive. Findings herald India and China as pinnacles of hydrogen demand, with South Korea and Japan tailing closely. The study forecasts the energy consumption for solar hydrogen production in G20 countries to oscillate between 3.02 and 2.89 million GWh in 2022, while production costs are anticipated to range from $8.47/kg to $10.01/kg. In an assertive scenario, the paper illuminates a pathway towards achieving a significant CO 2 reduction, unmasking environmental savings of up to a staggering 48%, equivalent to 1.5 million mtCO 2 , by 2050. [Display omitted] • Hydrogen demand of G20 countries is analyzed using GIS and techno-economic models. • The projected adoption rates of hydrogen vary among the G20 countries. • Solar energy is crucial in determining each region's annual energy demand. • China, US, and India have the highest solar potential throughout the year. • The environmental analysis shows 850–1.5 million mtCO2 total emissions by 2050. [ABSTRACT FROM AUTHOR]

In the hydrogen‐based integrated energy system (HIES), there exists a hydrogen trading market where hydrogen producers and consumers are distinct stakeholders. Current research in hydrogen trading predominantly focuses on high‐cost green hydrogen (GH), which is not aligned with the current trend of utilizing hydrogen from multiple sources. To address this, this paper proposes a hydrogen trading strategy between the virtual hydrogen plant (VHP) and electro‐hydrogen energy system (EHES) based on a bi‐level model, considering the synergy of GH produced from electrolyzers and blue hydrogen (BH) derived from natural gas in the HIES. In the VHP level, the objective is to maximize profit from hydrogen sales, allowing for the determination of hydrogen prices. In the EHES level, the goal is to minimize the cost of energy supply, leading to the formulation of GH and BH purchasing plans based on hydrogen prices. Additionally, this paper incorporates a risk‐averse model from the information gap decision theory (IGDT) to account for the impact of wind power output uncertainties in the VHP level. Subsequently, leveraging the Karush–Kuhn–Tucker (KKT) conditions of the EHES level, the bi‐level problem is transformed into a solvable single‐level mathematical program with equilibrium constraints (MPEC), with the non‐linear equilibrium constraints linearized. The proposed bi‐level optimization model is validated through case studies encompassing industrial and residential hydrogen utilization within the HIES. The outcomes confirm the rationality of the proposed model, demonstrating that, in comparison to exclusively trading GH, the coordinated GH and BH trading can increase the profit of the VHP by 2.7% and reduce the costs of the EHES by 8.5%. [ABSTRACT FROM AUTHOR]

To advance carbon neutrality policies, many countries are increasingly integrating Renewable Energy Sources (RESs) into their energy mix. However, for harnessing natural energy in power generation, RESs present challenges in output control, potentially leading to power imbalances. Such imbalances, when coupled with an excessive reliance on unpredictable RES, may necessitate the curtailment of grid-integrated renewable generation, halting production despite available capacity. This paper proposes strategies to mitigate the economic and operational efficiency impacts of increased RESs on the power grid. It focuses on the optimal operation of Battery Energy Storage Systems (BESSs) and Power to Gas (P2G) technology, which flexibly converts surplus electricity into hydrogen. By employing Mixed Integer Linear Programming (MILP) for optimization and Stochastic Programming (SP) for the management of the uncertainty of renewable energy output, this paper evaluates the anticipated benefits of BESS and P2G applications. [ABSTRACT FROM AUTHOR]

Water dissolved in nominally anhydrous minerals (NAMs) can be transported to deep regions of the Earth through subducting slabs, thereby significantly influencing the physicochemical properties of deep-Earth materials and impacting dynamic processes in the deep Earth. Stishovite, a prominent mineral present in subducting slabs, remains stable at mantle pressures of 9–50 GPa and can incorporate various amounts of water (H + , OH - , and H 2 O) in its crystal structure. Consequently, stishovite can play a crucial role in transporting water into the deep Earth through subducting slabs. This paper provides a comprehensive review of the research process concerning water (hydrogen) solubility in stishovite. The key factors that govern water solubility in stishovite are summarized as temperature, pressure, water fugacity, and aluminum content. Combined with published results on the dependence of water solubility on the aforementioned parameters, this paper proposes a new equation to describe the solubility of water in Al-bearing stishovite. Calculation results based on this equation suggest that stishovite may effectively accommodate water released from processes such as hydrous mineral breakdown, which could ultimately contribute to the presence of a water-rich transition zone. [ABSTRACT FROM AUTHOR]

In this paper, an economic life cycle assessment of hydrogen-fueled gas turbine power plant is developed, where hydrogen is produced via electrolysis with electricity generated from renewable resources (green hydrogen). By this way, the continuous green electricity without fluctuation can be generated. With a great potential in solar irradiation, Iran can be a major country for producing green hydrogen. For this purpose, first, we simulate a 100 MW solar PV plant in Fars province and calculate annual electricity generation. Considering capital cost (Capex) and operations and maintenance costs (Opex) of plants including PV, electrolyzer, hydrogen storage and distribution facilities, and gas turbine, we estimate levelized cost of electricity from green H2-fueled gas turbine power plant. Because hydrogen technology has not matured yet, the analysis for both 2021 and 2040 will be conducted. Due to lower marginal production costs, the increase in renewable energy sources decreases electricity wholesale prices. In this paper, we also estimate long-term merit order effect (MOE) of electricity generated by green hydrogen on electricity wholesale price. The results show that in renewable/hydrogen-based forecast for electricity mix of 2040, electricity wholesale price is estimated around 6.38 c$/kWh, nearly 38% less than present wholesale price. [ABSTRACT FROM AUTHOR]

In recent years, the catalyst efficiency of hydrogen evolution reaction (HER) has been extensively studied. However, the stability of catalysts at high current densities is still a challenge. Herein, layered Ni−Co−P was electrodeposited on carbon fiber paper (CFP) via cyclic voltammetry (CV). This low‐cost electrode exhibits high efficiency and excellent durability for HER in 1 M KOH. To achieve current densities of 10, 100, 500, and 1000 mA cm−2, Ni−Co−P/CFP required overpotentials of 49, 95, 170, and 295 mV, respectively. The layered structure allows the catalyst to fall off layer by layer. After the outer layer of catalyst falls off, the inner layer of catalyst will be exposed to continue working. After 300 h of HER at 1000 mA cm−2, Ni−Co−P/CFP still has a regular morphology and high efficiency. Our work shows that layered Ni−Co−P/CFP has excellent prospects for practical applications. [ABSTRACT FROM AUTHOR]

The effects of N/C, P/C and Fe/C ratios on dark fermentative hydrogen gas production from activated carbon treated WPT hydrolysate were investigated using Box–Behnken statistical experiment design. N/C, P/C and Fe/C ratios were chosen as independent variables while the H 2 yield and SHPR were set as the objective functions. H 2 yield and SHPR functions were described by two quadratic model functions. The addition of a proper amount of N, P and Fe to the fermentation media was found to be essential to enhance the H 2 production performance. Linear and interaction terms of N/C and Fe/C did have a significant effect on the H 2 yield in the model function. However, the SHPR was significantly affected by the linear and interaction terms of N/C and P/C. The most convenient N/C, P/C and Fe/C ratios resulting maximum H 2 yield (0.656 mol H 2 /mol glucose) and SHPR (241.64 mL H 2 /g biomass.h) were determined as 0.05, 0.09 and 0.003 (w/w), respectively. [ABSTRACT FROM AUTHOR]

The authors of the title paper (Appl Phys A 126:394, 2020) report to have grown a new nonlinear optical potassium hydrogen oxalate (KHO) single crystal, which exhibits second harmonic generation response. In this comment, it is shown that these claims are erroneous since KHO is a well-known solid which crystallizes in the centrosymmetric P21/c space group. [ABSTRACT FROM AUTHOR]

• Co doped MoS 2 was decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) by a solvothermal process. • The lattice spacing of (1 0 0) plane of Co-MoS 2 was slightly narrow than that of MoS 2. • The as-prepared Co-MoS 2 /NCFCP hybrids showed enhanced electrochemical activity for HER. In this paper, Co-doped MoS 2 (Co-MoS 2) with various Co/Mo mole ratio (6%–12%) decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) (Co-MoS 2 /NCFCP) is fabricated by a solvothermal method as an efficient electrocatalyst for hydrogen evolution reaction (HER). The NCFCP substrate is prepared by electrochemical deposition of polypyrrole on carbon paper followed by heat treatment. The obtained 9% Co-MoS 2 /NCFCP hybrid catalyst exhibits an excellent electrocatalytic HER activity with a low overpotential of 174 mV at 10 mA cm−2, a small Tafel slope of 52 mV dec−1 and long-term stability. Thus, Co-MoS 2 /NCFCP hybrid holds high potential as an efficient earth-abundant electrocatalyst material for HER. [ABSTRACT FROM AUTHOR]

Energy and transport are the two largest contributors to carbon emissions. In recent years, the transport sector has made strides in reducing its carbon footprint by producing electric vehicles that emit zero carbon. This paper investigates the use of Fuel Cell Electric Vehicles (FCEVs) with a newly developed regenerative suspension module (RSM). The RSM uses an electromechanical mechanism to obtain regenerative electrical energy from the engine and is mounted to the passive suspension system. To determine the potential energy savings of the RSM module, a hydrogen fuel cell electric vehicle simulated under specific road geometries, speeds, and acceleration conditions. The simulation results indicate that the Regenerative Suspension Modules (RSM) mounted on each wheel of the FCEV generate 2.5 times more energy than the regenerative braking system. This result is evaluated as an increase in efficiency and range in electric vehicles. • This study aimed to investigate efficiency gains from adding an RSM to hydrogen fuel cell electric vehicles. • This is the first study in literature to integrate RSM into a Fuel Cell Electric Vehicle. • The charging efficiency of the FCEV is improved by the Regenerative Suspension Modules mounted on each wheel. • The FCEV's Regenerative Suspension Module mounted on each wheel generates 2.5 times more energy than regenerative braking. [ABSTRACT FROM AUTHOR]