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Electrocatalytic water splitting is considered as a green and efficient way of hydrogen production. How to promote the performance of electrode and develop stable non-precious metal catalysts has caused extensive research. One of the effective strategies is combining two or more catalytic materials to build heterogeneous structures. In this paper, a series of Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 heterostructured materials were synthesized to in-situ grow Ni 3 S 2 /Ni 3 Sn 2 S 2 on Ni foam with a 3D porous structure by modulating the substance ratio of elemental cobalt and elemental sulfur through a one-step hydrothermal process. The materials have superior oxygen evolution reaction (OER) properties and urea oxidation reaction (UOR) performance. Under an alkaline electrolyte of 1 M KOH, for OER, Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 only requires overpotential of 251 mV to obtain a current density of 10 mA cm−2. In an alkaline solution of 1 M KOH +0.5 M urea, for UOR, only the potential of 1.326 V was demanded for the catalyst to reach a current density of 50 mA cm−2, but its stability over 15 h was average. Density Functional Theory (DFT) analyses suggest that Co–Ni 3 S 2 has better metallic properties and promote the dynamics in catalysis. This study put forward a new thought for future research on nickel-tin binary metal sulfide hybrid electrocatalysts with excellent freshwater, seawater and urea oxidation properties. In this paper, a series of Co x -Ni 3 S 2 /Ni 3 Sn 2 S 2 materials was in situ grown on Ni foam by a one-step hydrothermal method, and the synthesized Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 material present excellent water and urea oxidation properties. [Display omitted] • Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 materials were successfully synthesized by hydrothermal processes. • Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 electrode shows excellent catalysis in the cathode reaction of water and urea. • Co 0.3 -Ni 3 S 2 /Ni 3 Sn 2 S 2 requires only potential of 1.326 V to achieve a current density of 50 mA cm−2 for UOR. [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]

In order to meet the hydrogen refueling demand of fuel cell vehicles and reduce the cost of HRS operation process, it is necessary to study the hydrogen refueling process of cascade hydrogen storage system of hydrogen refueling station. In this paper, a thermodynamic model of the hydrogen refueling process for fuel cell vehicles is established, and the effect of the variation of these thermodynamic parameters on the specific energy consumption and utilization rate of the hydrogen refueling process is investigated in terms of the pressure ratio and capacity of the hydrogen storage tank, which is the core of the hydrogen refueling station, consisting of multiple hydrogen storage tanks. The results show that the specific energy consumption and hydrogen utilization of the hydrogen refueling station decreases as the ratio of the nominal pressure of the medium-pressure stage to the nominal pressure of the high-pressure stage increases over the course of the pressure ratio change. In addition, the capacity variation is only slightly changed as a result of the pressure ratio variation. Therefore, the lowest ratio of specific energy consumption can be found by fixing the utilization rate and by changing the pressure ratio. For example, in this paper, if the total mass of hydrogen in the station is 600 kg and the hydrogen utilization rate is required to be not less than 12 %, the optimal pressures for each level are 50.2 MPa, 65 MPa and 86.7 MPa. • A thermodynamic model of the hydrogen filling process for fuel cell vehicles is established. • The pressure ratio and capacity of cascade hydrogen storage systems were analyzed. • Specific energy consumption and hydrogen utilization are used as evaluation indicators. • The optimal pressures for each level are 50.2 MPa, 65 MPa and 86.7 MPa. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of subcooling degree and exhaust pressure on the performance of a high-pressure piston pump for pressurizing cryogenic liquid. We fabricate a lab-scale cryogenic liquid pump, conduct experiments with liquid nitrogen, and observe the significant effect of subcooling changes on the pump performance. The lab-scale pump achieves up to 30 bar of exhaust pressure and up to 45.4 g exhaust mass per cycle. This paper introduces the concept of duty cycle for the exhaust mass as a measure of pump performance. The results show that as the subcooling degree and the exhaust pressure increase, the duty cycle and the exhaust mass also increase, improving the pump performance. However, the increase in performance does not happen proportionally, and an optimal subcooling degree must be selected. This paper establishes a generalized computational model to predict the pump performance, achieving the mean absolute errors of 1.8 bar and 0.3 g/s in pressure and mass flow rate, respectively. The model can predict the exhaust mass during one stroke cycle of the pump with an approximation error of 10 %. In addition, the model predicts that pressurizing liquid hydrogen to 900 bar requires subcooling degree and its duty cycle cannot reach 100 % by reduction of specific volume. The findings suggest that subcooling can be used to enhance cryogenic liquid pump performance, and the optimal subcooling degree can be determined during the design of piston pumps to achieve high pressure. [Display omitted] • A piston-type tension-assisted cryogenic liquid pump was developed. • We identified the performance indicator of the pump as duty cycle. • This paper investigated the effect of the parameters on the duty cycle. • Subcooling degree effect on liquid hydrogen is predicted. [ABSTRACT FROM AUTHOR]

Unitized regenerative proton exchange membrane fuel cell (URPEMFC) as a self-sufficient hydrogen energy system offers a unique proposition for achieving a net zero emissions future. The system combines the operation of water. Due to the design parameters and operating conditions of URPEMFC, the potential cycling from the mode switching, high temperature, humidified environment and the long exposure of metallic components to hydrogen are the primary factors causing degradation to the system. Consequently, the conventional graphite bipolar plate (BP) suffers heavily under such an environment while giving rise to alternative metallic base materials, such as titanium, stainless steel, and aluminum. Various surface treatment and coating methods are currently under investigation to provide the required corrosion resistance while maintaining feasible manufacturing process and cost. This paper presents an overview into the degradation phenomena of URPEMFC that contributes to the corrosion of BP that is affecting the performance and future commercialization of the system. The operating condition of the system is summarized in terms of fuel cells and water electrolyzers respectively, along with the integration of both operations as a system. Next, the paper outlines the degradation phenomena observed on BP and the behavior of various materials under such conditions. The performances of various base and coating materials have been compiled as have characterization methods that are useful in measuring corrosion resistance. This paper aims to provide a better understanding on the overall degradation of BP in URPEMFC and overview of various material choices to identify the optimal corrosion mitigation solution. [Display omitted] • Breakdown of the URPEMFC operating parameters from the respective operation modes. • System design approaches allowing integration of fuel cell and electrolyzer modes. • Identification of the main degradation mechanism on the BP. • Tabulated data of various base materials and coatings performance. • Discussion of current experimental and modeling methods for corrosion resistance characterization. [ABSTRACT FROM AUTHOR]

This paper proposes a novel energy management strategy satisfying real-time and highly efficient energy management strategies for fuel cell hybrid electric vehicles (FCHEVs). The strategy is based on model predictive control (MPC), which integrates long short-term memory (LSTM) and dynamic programming (DP). A high-precision powertrain model of the investigated FCHEV is established for subsequent simulations. After training under several typical working conditions, LSTM is designed to forecast future power demands of the entire vehicle. Using the prediction results, the DP algorithm calculates the control scheme based on model predictive control. Considering the economy and durability of power sources, the results of four different control strategies are compared: thermostat, power following, traditional DP, and MPC. The MPC proposed in this paper reduces the total usage cost per 100 km on the test set by 9%, 33.5%, and −4.6%. • The economy and durability of vehicular fuel cell system are both considered. • The LSTM neural network is imported into MPC theory for vehicular power prediction. • The key parameters of MPC and LSTM are determined by referring to the greedy algorithm. • The computational load in MPC optimisation is reduced by simplifying DP algorithm. • The real-time performance of the supposed EMS on-board is validated. [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]

The fuel cells need the high step-up DC/DC converter with low current ripples to interface to the high voltage DC grid. A novel zero voltage switching high step-up multiphase interleaved boost converter (ZVS HSMIBC) is proposed in this paper. This new converter employs advantages of low input current ripples, high voltage step-up ratio, soft-switching operation, and low switching harmonics and noise. In this paper, the two-phase interleaved structure of the proposed ZVS HSMIBC is analyzed and researched in detail as a representative topology. The relevant conclusions also can apply to multiphase (3 and above) interleaved structure of the HSMIBC. Finally, an experimental prototype is built and test, the experimental results show that the proposed converter can operated under ZVS conditions with low input current ripples and low switching noise and harmonics. In addition, this converter can obtain high voltage step-up ratio up to 45 (mn = 8, d = 0.8) with high efficiency, and proportion of the experimental ratios to theoretical ratios is also high (not less than 0.8). • A high step-up multiphase interleaved boost converter is proposed for the fuel cell power system. • The converter includes soft-switching circuit, high voltage ratio circuit, and interleaved structure. • The converter employs advantages of low input current ripples, high voltage gain, and low switching harmonics. • The operating principle and performance of the converter is verified by an experimental prototype. [ABSTRACT FROM AUTHOR]

Using the WIEN2k code, first-principles simulations of ZrXH 3 (X = Zn, Cd) hydride perovskites are performed to determine their hydrogen storage properties. The purpose of this study is to investigate their structural, optoelectronic, hydrogen storage, mechanical and thermoelectric properties. The structural analysis demonstrates their stability through the heat of formation along with desorption temperature and shows that these compositions belong to the orthorhombic space group Cmcm (no.63). The band structure and density of states are estimated for electronic characteristics, indicating the metallic nature of both compositions. Analysis of elastic properties such as elastic constants, Pugh's ratio, bulk modulus, Poisson's ratio, and anisotropy factor are explored to determine the mechanical stability of these compositions and demonstrate their suitability as a transport medium in hydrogen storage systems even at higher pressure. To study the optical behavior of the perovskites under consideration for hydrogen storage applications, the dielectric parameters, dielectric constants, refractive index, optical conductivity, absorptivity, and energy loss function are studied. The present paper represents the initial theoretical effort toward future exploration of these materials for hydrogen storage applications. [Display omitted] Using the WIEN2k code, first-principles simulations of ZrXH 3 (X = Zn, Cd) hydride perovskites are performed to determine their hydrogen storage properties. The purpose of this study is to investigate their structural, optoelectronic, hydrogen storage, mechanical and thermoelectric properties. The structural analysis demonstrates their stability through the heat of formation along with desorption temperature and shows that these compositions belong to the orthorhombic space group Cmcm (no.63). The band structure and density of states are estimated for electronic characteristics, indicating the metallic nature of both compositions. Analysis of elastic properties such as elastic constants, Pugh's ratio, bulk modulus, Poisson's ratio, and anisotropy factor are explored to determine the mechanical stability of these compositions and demonstrate their suitability as a transport medium in hydrogen storage systems even at higher pressure. To study the optical behavior of the perovskites under consideration for hydrogen storage applications, the dielectric parameters, dielectric constants, refractive index, optical conductivity, absorptivity, and energy loss function are studied. The present paper represents the initial theoretical effort toward future exploration of these materials for hydrogen storage applications. • Stability of ZrXH 3 (X = Zn, Cd) hydride perovskites is confirmed by Enthalpy of formation. • ZrXH 3 (X = Zn, Cd) hydride perovskites have high value of decomposition temperature. • The gravimetric hydrogen storage capacities comes out to be 1.89 % and 1.46 % respectively. • Metallic behavior is reveled by electronic structure of these hydrides. [ABSTRACT FROM AUTHOR]

Guaranteeing rapid management of oxygen excess ratio (OER) for proton exchange membrane fuel cells (PEMFC) under load variations is a challenge with practical significance. To improve the controller response of PEMFC air supply system, a fixed time fault-tolerant control strategy is proposed in this paper. A fixed convergence time of PEMFC air supply control system is quantified and guaranteed by the proposed method and the control response can be accelerated by reducing the setting time. The contributions of this paper is fourfold. Firstly, the manifold leakage fault is estimated by fixed time fault observer, which can improve the real-time fault tracking performance of the control system. Secondly, a hierarchical fixed time sliding mode controller is proposed to regulate the OER rapidly. Furthermore, a novel adaptive term is employed to reduce the effects of the chattering from fault observer in the outer loop. Finally, the effectiveness of the proposed method is verified on a real-time PEMFC simulation platform. Experimental results on a Hardware-in-the-loop (HIL) platform show that the proposed fixed time fault tolerant control strategy has the characteristics of fast response and high robustness. [Display omitted] • Fixed time fault observer is employed to monitor the manifold leakage. • Fixed time control framework guarantees a quantified stabilization time of OER. • An adaptive term reduces the chattering effects of the fault observer. • The FTC method is validated on a high-fidelity HIL platform. [ABSTRACT FROM AUTHOR]

Previous studies have found that in ceramic fuel cells using Ni 0·8 Co 0·15 Al 0·05 LiO 2 (NCAL) as the electrode, lithium compounds such as LiOH generated by reduction of NCAL anode by H 2 diffuse into oxide electrolyte membranes such as Gd 0.1 Ce 0·9 O 2 (GDC), and the "GDC-lithium compounds" composite electrolyte formed online is an excellent proton conductor. In this paper, the low-temperature electrolysis performance of proton conductor type solid oxide electrolysis cell (P-SOEC) with GDC as electrolyte and NCAL as electrode for direct electrochemical conversion of H 2 O into H 2 was investigated. It is found that at operation temperature of 550 °C, the current density of the SOEC prepared in this paper can reach 2.263 A cm−2 at 1.6 V. The composite electrolyte in the electrolysis cell reaches an ionic conductivity of 0.572 S cm−1 in the SOEC mode. The excellent hydrogen production performance proves that this new type of electrolysis cell with lithium compounds as electrodes is a promising and potential proton conductive low-temperature SOEC. • SOEC with NCAL electrodes was fabricated. • Proton conductivity of the composite electrolyte reaches 0.572 S cm−1 at 550 °C. • The electrolytic current density of the SOEC reaches 2.263 A·cm−2 at 1.6 V. • Provided a new type of SOEC and related electrolytic cell material. [ABSTRACT FROM AUTHOR]

Due to the extra evaporation loss caused by the ortho-para hydrogen conversion (OPHC) during the storage and transportation of liquid hydrogen (LH 2), the initial concentration of ortho-hydrogen (o-H 2) plays an important role in the large-scale safe operation and utilization of LH 2. However, there are very limited studies focusing on clarifying the impact of the OPHC on thermal behaviors of LH 2 tanks. In light of this, this paper establishes and develops an extended thermal multi-zone model that couples the OPHC process with the mass and energy conservation equations of the ullage and liquid for an LH 2 tank. With the help of the model, a thermodynamic analysis of the pressurization rate is performed to obtain the dominant parameter that evaluates the effect of the initial o-H 2 concentration on the pressure build-up process. The results indicate that the interfacial mass transfer rate caused by the OPHC is the dominant parameter accounting for more than 90% of the effect of all parameters on the pressurization rate during a 10-day process with an initial liquid fill ratio of 90% and a heat leakage of 40 W. Additionally, the effect of the initial o-H 2 concentration on the optimal liquid fill ratio is discussed in this paper. The results indicate that when the initial o-H 2 concentration changes from 0.2% to 10%, the optimal liquid fill ratio decreases from 82.5% to 74%. The present work provides theoretical support and guidance for controlling the o-H 2 concentration to realize the long-term and high-efficiency storage of LH 2. • Modeling of transient ortho-para hydrogen conversion (OPHC) for LH 2 tanks. • Thermodynamic analysis coupled with OPHC on LH 2 storage is conducted. • Interfacial mass transfer by OPHC determines the pressure rise in LH 2 tanks. • Initial concentration of o-H 2 reduces the optimized liquid fill ratio of tanks. [ABSTRACT FROM AUTHOR]

Due to its excellent combustion properties and environmental performance, the development of hydrogen energy has become an international trend in recent years. However, hydrogen refueling stations, which are the infrastructure for hydrogen energy development, contain flammable gases such as hydrogen and methanol, which are highly susceptible to explosion and may threaten people's health and property safety. In this paper, a dynamic risk assessment method based on Dynamic Bayesian Network (DBN) is established for combustible gas leakage accidents in hydrogen refueling stations, and the methanol to hydrogen refueling stations and liquid hydrogen refueling stations are taken as research objects to quantitatively analyze their leakage risks and accident consequences. It is found that the leakage accident probability and consequences of methanol to hydrogen refueling stations show periodicity with a period of three months, while there is no periodicity for liquid hydrogen refueling stations. The probabilities of leakage accident and serious consequences in methanol to hydrogen refueling stations show a sudden increase within a cycle, on the other hand, those in liquid hydrogen refueling stations tend to increase linearly over three years with time. In addition, based on the diagnostic reasoning function of DBN, this paper identifies the two most critical hazard sources for flammable gas leakage accident in hydrogen refueling stations: human factors and corrosion factors, and provides guidance for relevant enterprises to reduce the risk. [Display omitted] • The DBN-based leakage risk assessment in two hydrogen refueling stations was finished. • The dynamic flammable gas leakage consequences in hydrogen refueling stations were achieved. • The key factors of gas leakage in hydrogen refueling stations were determined. • The commonalities and differences between two hydrogen refueling stations were compared. [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]

This paper proposes a novel SOFC based cogeneration system, consisting of biomass co-gasification, SOFC power generation and ORC waste heat recovery, to achieve the efficient and clean utilization of poultry litter. Based on the conceptual design, the energy, exergy and exergo-economic analysis are conducted, including sensitivity analysis, uncertainty analysis and multi-objective optimization. Results show that when using straw as the co-gasification biomass with poultry litter, the highest energy utilization efficiency of 44.70 % is obtained with the electricity and heat production of 162.02 kW and 52.41 kW, respectively. The biomass gasifier and the SOFC stack have the highest exergy destruction, accounting for 24.43 % and 19.99 % of the total. Sensitivity analysis presents complex results concerning mass fraction of poultry litter, water content, equivalent air ratio and water-carbon ratio, etc. The optimal solution for the current optimization problem is obtained. When poultry litter mass fraction is fixed at 25 %, T SOFC = 852 °C and u f = 0.73, the exergy efficiency is obtained as 41.95 % and the overall exergy cost per unit is obtained as 42.35 $/GJ. This paper investigates a novel cogeneration system relying on the biomass co-gasification of poultry litter, providing a new solution for poultry litter treatment and sustainable development of agriculture, forestry and husbandry. [Display omitted] • Biomass co-gasification, SOFC and ORC are integrated for poultry litter treatment. • Comprehensive energy, exergy and exergo-economic analysis are carried out. • Sensitivity analysis, uncertainty analysis and operational optimization are conducted. • High-value utilization process of the low-calorific poultry litter is proposed and studied. [ABSTRACT FROM AUTHOR]

The work presented in the paper focuses on the investigation of coupling high-temperature gas-cooled nuclear reactor (HTGR) with solid oxide electrolyzers (SOE) for large-scale production of hydrogen. In the analysis, four cases related to loads of the nuclear reactor were under consideration. These included operation at the nominal load (100%), as well part-load operation (25, 50 and 80%). Paper presents the assessment of several alternative modes of operation of the HTGR-SOE hybrid. It can be concluded that under the given assumptions, electrical loading of the electrolyzer can be varied between 5 and 31 A (for 25% and 100% load of HTGR, respectively), and the corresponding voltage is in the range from 1.03 to 1.29 V. In terms of the size of the hydrogen production island, the electric power of the electrolysis was in the range from 12.42 to 96 MW, while the heat necessary to operate the SOE was provided by the steam cycle of the HTGR. The work provides qualitative and quantitative assessment of the possibility of generating hydrogen in a hybrid system which addresses the off-design operation of the nuclear reactor. [Display omitted] • Coupling of high temperature gas-cooled nuclear reactors with SOE was studied. • Power load of the HTGR was modulated between 25% and 100%. • Current density of electrolysis was adjusted to control the process. • The maximum amount of hydrogen produces hourly was 2,800 tons. • Efficiency of SOE in the system varied between 49.86 and 89.11%. [ABSTRACT FROM AUTHOR]

This paper presents a review of modern methods for producing hydrogen, including extracting hydrogen from exhaust and purge gases of chemical industries. The technology for producing hydrogen by separation from hydrogen-containing gas obtained by partial oxidation of hydrocarbons in a high-temperature reactor (HTR) is considered. In the HTR combustion chamber, the following zones are distinguished: a combustion zone, a coking zone, and a conversion zone, i.e., a zone of hydrocarbon conversion, soot formation and soot conversion. The paper presents the results of an experimental and theoretical study of soot formation as well as the results of studying the influence of various process parameters in the HTR chamber on soot formation and burnout. A physical and chemical model for the combustion of methane with air oxygen in an HTR chamber has been developed, taking into account soot formation. Recommendations have been formulated for optimizing the process in the HTR and improving its design. • Review and comparison of modern methods for producing hydrogen. • Hydrogen production by partial oxidation of organic raw materials. • Results of an experimental study of soot formation in a high-temperature reactor (HTR). • Physico-chemical model of combustion and soot formation in HTR. • Analysis of the kinetic scheme of HTR in order to minimize soot formation during combustion. [ABSTRACT FROM AUTHOR]

Hydrogen is considered as a promising fuel in the 21st century due to zero tailpipe CO 2 emissions from hydrogen-powered vehicles. The use of hydrogen as fuel in vehicles can play an important role in decarbonising the transport sector and achieving net-zero emissions targets. However, there exist several issues related to hydrogen production, efficient hydrogen storage system and transport and refuelling infrastructure, where the current research is focussing on. This study critically reviews and analyses the recent technological advancements of hydrogen production, storage and distribution technologies along with their cost and associated greenhouse gas emissions. This paper also comprehensively discusses the hydrogen refuelling methods, identifies issues associated with fast refuelling and explores the control strategies. Additionally, it explains various standard protocols in relation to safe and efficient refuelling, analyses economic aspects and presents the recent technological advancements related to refuelling infrastructure. This study suggests that the production cost of hydrogen significantly varies from one technology to others. The current hydrogen production cost from fossil sources using the most established technologies were estimated at about $0.8–$3.5/kg H 2 , depending on the country of production. The underground storage technology exhibited the lowest storage cost, followed by compressed hydrogen and liquid hydrogen storage. The levelised cost of the refuelling station was reported to be about $1.5–$8/kg H 2 , depending on the station's capacity and country. Using portable refuelling stations were identified as a promising option in many countries for small fleet size low-to-medium duty vehicles. Following the current research progresses, this paper in the end identifies knowledge gaps and thereby presents future research directions. • Technological advancements of hydrogen production, storage and transport are reviewed. • Emissions and economic aspects of production, storage, transport and fuelling are analysed. • Refuelling protocols, temperature rise issue and its control strategies are discussed. • Recent progress of mobile hydrogen refueller is explored. • Challenges of hydrogen production to fuelling and future research directions are presented. [ABSTRACT FROM AUTHOR]

Environmental working conditions have a great impact on the power demand and fuel consumption of vehicles, and the rational use of road terrain information plays an important role in the improvement of vehicle economy and energy sources durability. In this paper, a fuel cell hybrid electric bus (FCHEB) energy management strategy (EMS) based on deep deterministic policy gradient (DDPG) algorithm taking into account future terrain information is proposed based on cyber-physical system (CPS) to reduce the economic cost of FCHEB. First, this paper implements the information exchange between the vehicle system and the network layer through CPS to obtain the environmental working conditions of the vehicle operation. Second, future terrain information is introduced into the framework for the first time with hydrogen consumption, battery degradation and fuel cell durability constraints to rationally allocate the power of the FCHEB. The results show that the proposed strategy improves the power battery durability by 7.39% and reduces the total operating cost by 5.76% compared to the EMS that ignores the future terrain information. • An energy management strategy that considers future terrain information is proposed. • The proposed strategy achieves an effective combination with cyber physical system. • A trade-off between hydrogen consumption and energy sources durability is achieved. • The proposed strategy reduces the total cost by 7.81% compared to NTI EMS. [ABSTRACT FROM AUTHOR]

With the rapidly evolving geo-political landscape and unceasing advancements in technology, sustainable energy security is a very important topic. Research indicates that electrochemical energy systems are quite promising to solve many of energy conversion, storage, and conservation challenges while offering high efficiencies and low pollution. The paper provides an overview of electrochemical energy devices and the various optimization techniques used to evaluate them. The optimization techniques include linear regression, factorial design, the Taguchi method, artificial neural networks, filters, and a combination of such methods to improve these systems. To support the growing interest in research, the bulk of this study focuses on a review of the most promising and highly researched electrochemical energy devices, such as fuel cells, batteries, and supercapacitors. The paper also provides modest commentary on hydrogen production technologies, electrochemical reactors, and membrane separation technologies, amongst other technologies. Building on a previous paper by the authors of this paper on artificial intelligence in hybrid renewable energy systems with fuel cells, this work provides a comparative review of optimization techniques for supercapacitors by highlighting key findings based on model accuracy. A summary of the advantages and disadvantages of the different major optimization techniques is presented. The paper concludes that a combination of optimization techniques is used to overcome the drawbacks of individual techniques, with adaptive filters being the most widely studied. This paper presents studies on the Design of Experiments (DoE) with the goal of building a better understanding of the relationships that exist between different operating variables in various electrochemical devices. • The electrochemical systems can be optimized for better performance with high accuracy. • The optimization techniques used are either model-based or data-driven. • Linear regression and artificial neural networks are the most common techniques studied. • Hybrid models could be applied to enhance systems' accuracy and minimize errors. [ABSTRACT FROM AUTHOR]

An alkaline electrolyzer is a traditional equipment to generate hydrogen. Improving the yield of electrolyzers has recently captured much attention. In this regard, the utilization of carbon-coated nanomaterial structures is a state-of-art method. On the other hand, considering the current crisis of fossil energies, the exploitation of renewables and green technologies is necessary and unavoidable. Additionally, the design and development of integrated energy systems with two or more output products and the maximum usage of thermal losses to enhance productivity can increase the flexibility and acceptability of the energy system. In this regard, the current paper develops a framework for the performance of a new solar and biomass energies-driven multigeneration system (MGS). The main units installed in MGS are three electric energy generation units based on a gas turbine process, a solid oxide fuel cell unit (SOFCU) and an organic Rankine cycle unit (ORCU), a biomass energy conversion unit to useful thermal energy, a seawater conversion unit into useable freshwater, a unit for converting water and electricity into hydrogen energy and oxygen gas via a nanomaterial-based alkaline electrolyzer, a unit for converting solar energy into useful thermal energy (based on Fresnel collector), and a cooling load generation unit. The planned MGS has a novel structure and layout that has not been considered by researchers in previous papers. The current article is based on presenting a multi-aspect evaluation in order to investigate thermodynamic-conceptual, environmental and exergoeconomic analyzes. The outcomes indicated that the planned MGS can produce about 6.31 MW of electrical power and 0.49 MW of thermal power. Furthermore, MGS is able to produce various products such as potable water (∼0.977 kg/s), cooling load (∼0.16 MW), hydrogen energy (∼1.578 g/s) and sanitary water (∼0.957 kg/s). The overall energy and exergy productivities were measured as 78.13% and 47.72%, respectively. Also, the total investment and unit exergy costs were 47.16 USD per hour and 11.07 USD per GJ, respectively. Further, the content of carbon dioxide released from the planned system was equal to 10.59 kmol per MWh. A parametric study has been also developed to identify influencing parameters. • The nanomaterial-based alkaline electrolyzer is utilized for hydrogen production. • The system is tested by thermodynamic and environmental aspects. • The developed system was capable of generating 1.578 g/s hydrogen energy. • The content of carbon dioxide released from the planned system was less than traditional systems. [ABSTRACT FROM AUTHOR]

This paper provides a cost-effective energy management method for the microgrid's standalone and on-grid operational modes. The considered microgrid based on Green-to-Green systems such as a photovoltaic array (PV), wind turbine (WT) as renewable generators, hydrogen fuel cell (FC) system, microturbine (MT), and battery storage system. The suggested technique is based on the marine predator algorithm (MPA) that and created for a scheduling horizon of one day. The main objective of this paper is to reduce operating costs while satisfying the demand power. To approve the performance of the suggested management strategy, the simulation results are compared with other recent optimization algorithms. These algorithms include particle swarm optimization (PSO), salp swarm algorithm (SSA), and coot optimization algorithm (COOT). To approve the performance of the proposed EMS, the system will be evaluated for three cases: free renewable generation, restricted generation mode, and unlimited main grid power mode. For the first case, the proposed EMS reduces the operating costs by 0.8732%. For case 2, the economic benefits have been raised by 1.0815% and by 0% for the last case because of the reduced problem complexity. • A cost-effective energy management strategy for the microgrid based PEM fuel cells is proposed. • Implementation of marine predator algorithm to minimize the operating costs. • The performance has been investigated under various operating conditions. [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]

The merits of adjustable structure and composition and wide source of raw materials have convinced researchers to become more and more obsessed with the discussion of perovskite oxide materials and materials with perovskite structure in recent years. Perovskite type materials with excellent performance and well structural composition are expected to replace Pt/C, IrO 2 and RuO 2 , which are considered to be the most advanced active, valuable and cost-effective catalyst materials in the future. Therefore, finding catalysts with relatively higher economic and catalytic efficiency have always been the ideal goal of research for hydrogen production and O 2 /N 2 reduction. A large number of scholars have made significant efforts in developing various catalysts that remarkably enhance the catalytic activities of hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and nitrogen reduction reaction (NRR). This review aims to summarize some significant achievements in obtaining high-performance perovskite in the main related electro-catalysis field in recent years and provide a reference for the subsequent development of perovskite. This paper introduces the detailed methodology of the preparation of perovskite and discusses the design strategy of perovskite performance enhancement as important entry points to optimize the activity of perovskite. The paper comprehensively reviews the preparation methods of various perovskite with various examples, and also compares their advantages and disadvantages. To improve perovskite performance, most of the existing design strategies are introduced and integrated and novel design schemes are also displayed. The paper finally suggests the improvement potential in perovskite activity, aiming to create better design schemes of new perovskite in the future. • Conventional and new preparation methods of perovskite oxides catalysts are summarized. • Perovskites for hydrogen generation via hydrogen evolution reaction were summarized. • Perovskites for oxygen generation via oxygen evolution reaction were summarized. • Perovskites for nitrogen fixation via nitrogen reduction reaction were summarized. • Further performance improvement strategies of perovskite catalysts for electrochemistry are summarized. [ABSTRACT FROM AUTHOR]

Shifting from fossil fuels to clean alternative fuel options such as hydrogen is an essential step in decarbonising the road freight transport sector and facilitating an efficient transition towards zero-emissions goods distribution of the future. Designing an economically viable and competitive Hydrogen Supply Chain (HSC) to support and accelerate the widespread adoption of hydrogen powered Heavy Goods Vehicles (H 2 -HGVs) is, however, significantly hindered by the lack of the infrastructure required for producing, storing, transporting and distributing the required hydrogen. This paper focuses on a bespoke design of a hydrogen supply chain and distribution network for the long-haul road freight transportation in the UK and develops an improved end-to-end and spatially-explicit optimisation tool to perform scenario analysis and provide important first-hand managerial and policy making insights. The proposed methodology improves over existing grid-based methodologies by incorporating spatially-explicit locations of Hydrogen Refuelling Stations (HRSs) and allowing further flexibility and accuracy. Another distinctive feature of the method and the analyses carried out in the paper pertains to the inclusion of bulk geographically agnostic, as well as geological underground hydrogen storage options, and reporting on significant cost saving opportunities. Finally, the curve for H 2 -HGVs penetration levels, safety stock period decisions, and the transport mode capacity against hydrogen levelized cost at pump have been generated as important policy making tools to provide decision support and insights into cost, resilience and reliability of the HSC. [ABSTRACT FROM AUTHOR]

There is currently a "mother-daughter" model for hydrogen refueling stations (HRS). On-site "mother" stations produce hydrogen from city natural gas or water electrolysis, and off-site "daughter" stations are supplied with hydrogen from nearby on-site stations. This HRS system is a micro hydrogen supply chain that includes hydrogen suppliers, retailers, and end consumers characterized via demand functions. The present paper designs an optimal business model for this distributed HRS system using a multi-level game model, given that on-site and off-site HRS can operate individually or as a coalition to supply hydrogen. Stackelberg game and Shapley value models are constructed to explore how cooperative operation is superior by generating more profits than separate operation. Accordingly, in order to promote cooperation between on-site and off-site operators of HRS, an evolutionary game model is developed to investigate the allocation of profits and coordinated costs on the equilibrium of cooperative operation. The authors conclude that boosting the initial probabilities of actors to choose cooperative strategies and decreasing the coordinated cost can lead the game system to the ideal consequence. The present paper offers recommendations including establishing regulation standards for HRS operation, and advancing the information technology to design a more effective cooperative mechanism. • A business model of the hydrogen distribution is designed by multi-level games. • The centralized cooperation mode is better than the decentralized separation mode. • Reduction in the communication cost can help to achieve the cooperative mode. • Regulation and information technology related to the hydrogen should be enhanced. [ABSTRACT FROM AUTHOR]

Fuel Hydrogen cells become nowadays a major candidate to replace the diesel in powering the traction locomotives since they offer low emission of pollutant gases, high efficiency, and flexible modular structure without the need for installation of electrification infrastructure for railway networks. However, they cannot respond appropriately to the fast load transients due to their slow internal electrochemical and thermodynamic responses. Therefore, they shall be integrated with fast dynamics Li-ion battery cells to form a hybrid power source for traction systems. Accordingly, this paper presents a development of a new smart integrated power source of fuel hydrogen and Li-ion battery cells to supply dual three-phase machines for driving the trains in railway networks. The developed control management system is regulating the two power sources according to the train operational modes as well as the battery state of charge. In addition to that, dual three-phase machines offer several superiorities over the conventional three-phase machines such as lower harmonic distortion and power losses along with higher power density and fault tolerance. A designated railway line is nominated through selection criteria in this paper for the implementation of the new smart drive traction system in HIL platform using Typhoon HIL real time simulator. Moreover, an optimization analysis has been carried out to reduce the overall hydrogen consumption with the same journey time spent for a designated railway line using particle swarm optimization approach. Finally, a case study is presented to illustrate a proof of concept for designing the hydrogen refueling station for such railways which are supplied by the new integrated power source of fuel hydrogen and Li-ion battery cells. The case study investigates the site selection, operational assessment, and equipment requirements. • Smart hybrid power source of fuel hydrogen and Li-ion battery cells is developed to supply dual three-phase machines for driving the trains. • The management system regulates the power sources according to the train operational modes as well as the battery state of charge. • The new drive traction system is validated in hardware-in-the loop platform using Typhoon real-time simulator. • Optimization analysis is also carried out to reduce the overall hydrogen consumption using particle swarm optimization approach. • Li-ion battery cells are optimized to act as an energy storage buffers by keeping their states of charge at start and end of the journey the same. [ABSTRACT FROM AUTHOR]

Deploying renewable hydrogen presents a significant challenge in accessing off-takers who are willing to make long-term investments. To address this challenge, current projects focus on large-scale deployment to replace the demand for non-renewable hydrogen, particularly in ammonia synthesis for fertiliser production plants. The traditional process, involving Steam Methane Reformers (SMR) connected to Haber-Bosch synthesis, could potentially transition towards decarbonisation by gradually integrating water electrolysis. However, the coexistence of these processes poses limitations in accommodating the integration of renewable hydrogen, thereby creating operational challenges for industrial hubs. To tackle this issue, this paper proposes an optimal dispatch model for producing green hydrogen and ammonia while considering the coexistence of different processes. Furthermore, the objective is to analyse external factors that could determine the appropriate regulatory and pricing framework to facilitate the phase-out of SMR in favour of renewable hydrogen production. The paper presents a case study based in Spain, utilising data from 2018, 2022 and 2030 perspectives on the country's renewable resources, gas and electricity wholesale markets, pricing ranges, and regulatory constraints to validate the model. The findings indicate that carbon emissions taxation and the availability and pricing of Power Purchase Agreements (PPAs) will play crucial roles in this transition - the carbon emission price required for total phasing out SMR with water electrolysis would be around 550 EUR/ton CO 2. • Addressing the co-existence of steam methane reformers and electrolysers. • Novel power dispatch model addressing the flexibility of co-existential pathways. • PPA availability and pricing and ETS taxation as key enablers of renewable hydrogen. • Carbon intensity constraints heavily impact the project's sizing and feasibility. • Techno-environmental study of the carbon intensity of ammonia production. [ABSTRACT FROM AUTHOR]

With the growing demand for green technologies, hydrogen energy devices, such as Proton Exchange Membrane (PEM) fuel cells and water electrolysers, have received accelerated developments. However, the materials and manufacturing cost of these technologies are still relatively expensive which impedes their widespread commercialization. Additive Manufacturing (AM), commonly termed 3D Printing (3DP), with its advanced capabilities, could be a potential pathway to solve the fabrication challenges of PEM parts. Herein, in this paper, the research studies on the novel AM fabrication methods of PEM components are thoroughly reviewed and analysed. The key performance properties, such as corrosion and hydrogen embrittlement resistance, of the additively manufactured materials in the PEM working environment are discussed to emphasise their reliability for the PEM systems. Additionally, the major challenges and required future developments of AM technologies to unlock their full potential for PEM fabrication are identified. This paper provides insights from the latest research developments on the significance of advanced manufacturing technologies in developing sustainable energy systems to address the global energy challenges and climate change effects. • The AM technologies relevant to PEM fabrication are reviewed. • Corrosion performance of AM materials in the PEM working environment is presented. • The challenges and prospects of AM for PEM fabrication are discussed. • AM has the potential to revolutionize the fabrication of PEM systems. [ABSTRACT FROM AUTHOR]

The identification of the technical cooperation mode in the field of hydrogen energy is of great importance in guiding technological innovation. Based on the social network analysis (SNA) and spatial network method, this paper constructs the technical cooperation graph of China's industry-university-research (IUR) tripartites in the field of hydrogen technology. Based on the performed graphs, it shows the game and evolution of hydrogen technology innovation in three stages, respectively 2000–2010, 2011–2015 and 2016–2019. Meanwhile, this paper calculates the changes of network indicators and found that: (1) the network density showed a downward trend, from the initial 0.062 to 0.003. (2) The degree centrality of the network decreased from 14.7% to 5.7%. (3) The average path length and clustering coefficient indicate that the internal connections within the network were relatively close from 2000 to 2010, and had small-world characteristics. From 2016 to 2019, although the clustering coefficient increased, the average path length also increased significantly, indicating that the internal connections of the network did not become closer. From the network characteristics, the collaborative innovation network of China's hydrogen energy industry continues to expand in scale and scope, and the cooperation relationship is stable. However, it shows the characteristics of low network density and loose cooperation relationship, gradually developing into a scale-free network. Developed provinces and cities in North and East China occupy core positions in the industry-university-research network, while other regions are gradually expanding their cooperation efficiency; however, the overall cooperation frequency is relatively low in Northeast China, and most provinces and cities in South and Northwest China are in edge positions with poor collaboration capabilities. • Network analysis sheds light on China's hydrogen energy tech cooperation via patent. • Collaborative innovation in hydrogen technology evolves through three stages. • Tight internal connections with small-world properties seen in network (2000–2010). • Network's internal connections didn't become closer (2016–2019). • Network transforms from a stable and expanding structure into a scale-free network. [ABSTRACT FROM AUTHOR]

This paper presents research on the impact of the material microstructure on the performance of Molten Carbonate Fuel Cells (MCFC). The study is motivated by the need to increase the operation time of MCFC stacks. As the MCFC stacks are mainly composed of porous materials, the paper shows the impact of the porosity on both fuel cell performance and degradation rate. The study is based on the mathematical model, validated through experiments with varying microstructure parameters, achieving an overall relative error of 8%. The study evaluated the performance of MCFC using anodes with different porosity and found that increasing anode porosity from 40% to 70% led to a nearly two-fold increase in maximum power density. However, from both the degradation test and polarization curves, the optimal level of porosity for the anode is around 55%. The porosity level at 55% ensures the highest catalytic surface of the electrodes and is a compromise between the mechanical properties of the electrode and its electrochemical properties. • New approach of 0D model of MCFC including materials microstructure influence is proposed. • The new model is prepared in MS Excel and Aspen HYSYS environments. • Experimental investigation for materials with predefined microstructire parameters was performed for model validation. • Variant analysis is presented for different porosity, tortuosity and constrictivity of MCFC anode. • An optimal scenario is suggested based on modleing results. [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]

The development of large energy systems based on renewable energy sources is accompanied by an increase in the input capacities of large grid storages. Taking into account the vector for decarbonization and maneuverability, the use of hydrogen as a fuel in the cycle of a diabatic compressed air energy storage (CAES) is a promising scientific and technical direction. This paper analyzes the key performance indicators of a compressed air energy storage in the presence and absence of thermal energy recovery within the cycle. In addition, an assessment was made of the prospects for the use of a methane-hydrogen mixture in gas turbines. At the end of the paper, a calculation of the process of plasma pyrolysis of methane is given as one of the possible methods for the production of hydrogen for use in energy purposes. [ABSTRACT FROM AUTHOR]

Recently, ammonia is getting more attractive as a potential alternative fuel for future power generation and transportation purposes due to its ability to reduce consumption of fossil fuels, soot, CO 2 emissions, and hydrocarbon pollutants. In the recent past, several studies aimed to the development of ammonia combustion systems have been conducted. However, ammonia combustion systems face several challenges, such as poor ignition timings, lower burning velocity, low energy density, shorter flammability limits than hydrocarbons. These issues are compounded by the significant increase in NOx emissions, which makes practical application of ammonia challenging. Various conventional methods, such as blending ammonia with other hydrocarbons and hydrogen, have been employed to improve combustion performance and reduce NO x emission. Meanwhile, it increased the engine complexities and at the same time, it raised CO 2 and NO x emissions. Recently, plasma-assisted combustion (PAC) has emerged as a promising technology to boost the ammonia combustion process by improving ignition delay timings, increasing flame speed, extending flammability limits, and reducing NO x emissions. In recent years, plasma-assisted combustion (PAC) has emerged as a promising technology to enhance the ammonia combustion process by improving ignition delay timings, increasing flame speed, extending flammability limits, and reducing NOx emissions. Nevertheless, only a few studies on plasma-assisted ammonia combustion (PAAC) are available in the literature. This review paper aims to summarize the latest advancements in the field of PAAC during the last years, including progress in the development of numerical models and experimental studies. The paper highlights the detailed procedure of PAAC numerical modeling and the limitations of numerical models. Finally, the latest numerical and experimental developments of PAAC have been discussed. • Ammonia is getting more attraction as an alternative fuel for future power and transportation sectors. • A comprehensive outlook of non-thermal plasma for ammonia combustion is provided. • The in-depth mechanisms of plasma assisted combustion are highlighted. • The latest numerical and experimental studies of Plasma assisted combustion were analyzed. [ABSTRACT FROM AUTHOR]

Coupling water electrolyzers with solar and wind sources may be a promising solution in the near future for utilizing excess renewable energy. Indeed, many researchers have investigated various green hydrogen production systems, but a systematic approach should be developed to compare them. In addition, it is crucial to understand which solar and wind-based green hydrogen production systems have been studied and the literature gap on this topic. This review presents the latest research on green hydrogen production systems integrated with solar and wind technologies. One of the most significant novelties of this paper is to suggest a preliminary pathway and standardization strategy for the comparison of different green hydrogen production systems based on solar and wind sources. Various data and information are extracted from the most relevant papers in this field, such as renewable systems investigated, the location of the studied system, connection with the electrical grid, research type developed, final utilization of hydrogen considered, and performance indicators employed. This work will be an introductory guide for the community interested in green hydrogen production systems. • Comparison of solar and wind-based hydrogen production systems. • The combination of a water electrolyzer with solar and wind energy may be a promising solution. • More attention is needed on transient electrolyzer behaviour, battery degradation, and grid stability. [ABSTRACT FROM AUTHOR]

In this paper, based on the first-principle calculations of hybrid density functional theory, the MoSTe/g-GeC of the Z-scheme heterostructure is constructed. The stability, electronic properties, optical absorption properties, and photocatalytic mechanism of the heterostructure is investigated. The band structure of MoSTe/g-GeC heterostructure is staggered, and the bandgap is 0.47 eV. The built-in electric field from g-GeC to MoSTe, with a size of 1.03 eV. The optical absorption coefficient of MoSTe/g-GeC heterostructures is significantly higher than that of MoSTe and g-GeC layer. When pH ranges from 0 to 7, the reduction reaction occurs in g-GeC layer, and the oxidation reaction occurs in the MoSTe layer. In the MoSTe/g-GeC heterostructure under different stresses, the band structure is arranged in a staggered manner. Importantly, under tensile strain, the bandgap of MoSTe/g-GeC heterostructure can be changed from the indirect into a direct bandgap. The bandgap of heterostructure decreases under the strain. In addition, the analysis of the photocatalytic mechanism shows that the redox reaction of the MoSTe/g-GeC heterostructure occurs on the layer with strong redox ability, and their light absorption ability is significantly enhanced compared to single-layers, which effectively improves the photocatalytic properties. It's a potential high-efficiency photocatalytic materials for direct Z-scheme heterostructure. In this paper, the stability, electronic properties, optical absorption properties, and photocatalytic mechanism of the MoSTe/g-GeC heterostructure is systematically studied. The results show that the heterostructure is a direct z-scheme heterostructure, and the photocatalytic performance is better than that of MoSTe and GeC monolayers. [Display omitted] • MoSTe/g-GeC heterostructure is a direct Z-scheme heterostructure, which is suitable for photocatalytic water splitting. • MoSTe/g-GeC heterostructure has excellent absorption coefficient (9.8 × 104 cm−1) in the visible and ultraviolet ranges. • The bandgap of MoSTe/g-GeC heterostructure can change from indirect bandgap to direct bandgap under partial strain. [ABSTRACT FROM AUTHOR]

To explore more possibilities for hydrogen economy, Mg-based alloys containing long period stacking ordered (LPSO) phase for solid-state hydrogen storage deserve attention. In this paper, indium (In) element is adopted to alter the de/hydrogenation abilities of Mg–Y–Zn alloys. The relationship between microstructural features and hydrogen storage behaviors of Mg 95 Y 3 Zn 2- x In x (x = 0, 1 and 2 at.%) alloys are discussed in detail. Indium element can modify the morphology of LPSO phase and more Mg interfaces are obtained. LPSO phase cannot be generated when Zn is completely replaced by In element; instead α-Mg grains and eutectic phase (Mg + MgYIn) the constitute the In 2 alloy. Element In benefits the activation process of the alloys in this paper, which helps the alloy particles to be hydrogenated quickly in the first hydrogenation. Specifically, 1 at.% In substitution for Zn accelerates dehydrogenation and the dehydrogenation temperature reduces by 11 °C. The benefits of In element for dehydrogenation behaviors mainly come from increased Mg grain boundaries, larger MgH 2 lattice constants with weaker Mg–H bonds, uniformly distributed nanoscale YH 2 /YH 3 phase. • Indium can modify the morphology of LPSO phase with rough boundaries. • Indium substitution for Zn increases the MgH 2 cell volume, weakening Mg–H bonds. • Nanosized YH 2 and Indium alloying synergistically reinforce the hydrogen desorption. [ABSTRACT FROM AUTHOR]

The hydrogen supply system (HSS) is an important part to ensure the efficient and reliable operation of fuel cells. As one of the key equipment of hydrogen supply system, the hydrogen circulation pump (HCP) has a significant impact on improving the utilization rate of hydrogen and the output characteristics of fuel cell stacks. Considering the function and operating conditions, this paper proposes the design requirements for HCPs. The principles and characteristics of several mechanical pumps that can be used for hydrogen circulation are introduced, including root pump, claw pump, vortex pump, and centrifugal pump. And the research progress and technical innovation of these four types of HCPs are summarized. Then, the control methods and purge strategies of the hydrogen supply system with an HCP are also summarized. And the performance parameter of HCP products in the current market is compared. Finally, the possible solutions are given to address some challenges faced by the actual operation of HCPs, including hydrogen safety issues, cold start at low temperature, leakage, vibration, and noise. This paper is helpful for researchers to understand the overall research progress of HCP and provide a reference for optimizing the performance and achieving more efficient hydrogen circulation. • Proposing design requirements for hydrogen circulation pumps. • Summarizing the research progress in structural design and performance analysis. • Providing feasible solutions to the challenges faced in actual operation. • Control of hydrogen supply system with a hydrogen circulation pump is complicated. • Water and heat management in hydrogen circulation pumps needs to be studied. [ABSTRACT FROM AUTHOR]

The plateau environmental adaptability of the proton exchange membrane fuel cell (PEMFC) is a key technical challenge for the development of fuel cells (FCs). This paper reviews the current research on the adaptability of FCs in plateau environments, focusing on the application requirements of automotive FCs in high-cold and high-altitude areas. First, the paper investigates how low temperature and low pressure affect the internal structure and output performance of FCs in plateau environments. Second, it analyzes the recent advances in FC technology to cope with plateau environments and evaluates the technical advantages and disadvantages of various approaches based on essential indicators such as FC output performance, efficiency, and response time. Finally, it identifies future research directions in FC plateau environmental adaptability technology, aiming to provide a reference for using FCs in plateau environments. • Reviewed the development status of plateau environmental adaptation technology for fuel cells. • Analyzes the advantages and disadvantages of various cold start solutions. • The advantages and disadvantages of altitude adaptation technology are analyzed. • Suggests the future research focus of fuel cell plateau environmental adaptation technology. [ABSTRACT FROM AUTHOR]

A solid oxide electrolyzer cell (SOEC) is a promising clean energy technology due to with high conversion efficiency and the ability to directly produce syngas. This paper summarizes technical challenges of SOEC in terms of dynamic response, co-electrolysis and material degradation, and recent developments on the manufacturing technology, materials for each component, mathematical models, flow channel designs and reversible solid oxide fuel cells (RSOFCs). The model development and related research on SOECs are explored in this paper, encompassing sensitivity analyses, dynamic responses, structural degradation and practical applications. This paper aims to promote the future development of SOECs, including the improvement of electrolysis efficiency, lifetime and economic performance. • Technological limitations and recent developments for SOEC are reviewed. • The dynamic response, co-electrolysis and material degradation are discussed. • Component materials and their manufacturing techniques are summarized. • Multi-physics coupling models at different scales are highlighted. • Future research direction in materials and modeling are proposed. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cell (SOFC) is regarded as a promising energy conversion device because of its advantages such as high efficiency and fuel flexibility. With the advent of aviation electrification era, SOFC has been gradually studied as aviation power system. However, the high temperature operation and temperature gradient of SOFC bring challenges to practical application. Nowadays SOFC systems often use excessive air as coolant to reduce the temperature gradient of SOFC, which leads to the increases of the fuel consumption and reduction of the power generation efficiency. In order to maintain a lower temperature gradient with less air, a supercritical fuel cooled SOFC scheme is proposed in this paper. By establishing a one-dimensional model of conventional air-cooled fuel cell and fuel cell with fuel cooling channel. Through calculating the fuel cell temperature gradient under different working conditions, the results show that when the excess air coefficient (EAC) is 3, the temperature gradient of air-cooled SOFC reaches 22.7K/cm, while the temperature gradient of SOFC with fuel channel decreases to 8.35K/cm. Therefore, the SOFC with fuel channel can effectively reduce the use of air, reduce parasitic power consumption and improve the efficiency of the system while maintaining a lower temperature gradient. • A supercritical fuel cooled SOFC scheme is proposed in this paper. • When the excess air coefficient is 3, the temperature gradient of fuel cell with fuel channel decreases to 8.35K/cm. • The fuel cell system with fuel channel can effectively reduce the use of air. • The SOFC scheme of fuel cooling can improve the electrochemical performance of SOFC. [ABSTRACT FROM AUTHOR]

A broad consensus has been formed around global greenhouse gas emission reduction, and the task of realizing carbon reduction and decarbonization in the shipping industry is getting increasingly severe. Low-carbon and zero-carbon fuel power is the most direct and effective way to reduce ship emissions. However, it is difficult to form a mature power system configuration in designing, constructing, and applying low-carbon and zero-carbon fuel-powered ships due to the constraints of waters, routes, ship types, demand, power, alternative fuels, carbon emission reduction policies, and other dimensions. Based on this situation, to fill in the top-level architecture of the ship green power system and form a preliminary ship green power system configuration, this paper constructs a "demand-configuration-integration-system evaluation" architecture of ship green power system based on zero-carbon fuels from two kinds of zero-carbon fuels, i.e., hydrogen and ammonia. First, the demand for green ship power systems is sorted out, and the five ship system configuration elements, namely, fuel, power module, propulsion mode, aftertreatment mode, and propulsion module, are summarized. Then, the systems are combined and integrated, and the steps of the assessment of zero-carbon ship power systems are summarized by taking three typical power system configurations, namely, internal-combustion engine, fuel cell, and hybrid power systems, as examples. The green zero-carbon power system architecture proposed in this paper not only includes three kinds of inland near-sea and oceanic water requirements but also involves different ship types, such as container ships, bulk carriers, cruise ships, offshore engineering vessels, which can provide specific ideas and references for the designers/owners when designing and selecting a new type of zero-carbon powered ship. [Display omitted] • A ship zero carbon power system architecture has been constructed. • Sorting out zero-carbon power needs from waters, routes, and ship types. • Constructing the zero-carbon ship power system from five dimensions. • Demand, configuration, integration, and evaluation form a selection closed-loop. [ABSTRACT FROM AUTHOR]

Fuel cell hybrid electric vehicles (FCHEV) are one of the most promising new energy vehicles. The cost and lifetime of its powertrain have limited its commercial development. This paper proposed an energy management strategy based on nonlinear model predictive control (NMPC) technology to solve the economy and durability problem of FCHEVs. Based on Markov Monte Carlo(MCMC) method, a prediction model of multi-scale operating conditions is established, and dynamic programming(DP) is used to realize the optimal control in the predicted time domain. The "constant speed prediction" is innovatively adopted in the transition stage to improve the prediction accuracy and enable the model to be realized online. The ways to reduce calculating amount of NMPC are also discussed in this paper. This simplification leads to suboptimal fuel economy and durability of control system but can have obvious reduction in calculating time. The simulation results show that, compared with the thermostat strategy and the power following strategy, the degradation cost decrease of 11.1% and 23.9% and the total operation cost of NMPC decrease of 11.0% and 23.5% respectively. The NMPC strategy has better economy and durability than the rule-based energy management strategy, is close to the global optimal result obtained by dynamic programming and can meet the requirements of real-time control. • The economy and durability of vehicular fuel cell system are both considered. • Markov Chain Monte Carlo is imported into MPC theory for vehicular power prediction. • Adaptability to changing conditions is strengthened via "constant speed prediction". • The computational load in MPC optimization is reduced by simplifying DP algorithm. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell vehicles (HFCVs), as an important strategic path for global sustainable development and energy transition, have now become an important support for the global energy and transportation sectors. The United Kingdom, Japan, the United States, China, and other countries are vigorously developing HFCVs and increasing the construction of hydrogen stations. Before HFCVs enter the stage of rapid commercialization and development, it is necessary to investigate the factors that influence consumer HFCV adoption. In this paper, meta-analysis used 24 pieces of literature to include in a systematic evaluation of the existing research on the factors that influence consumer willingness to purchase HFCVs, setting influencing factors as the dependent variable, to clarify the specific roles of different influencing factors and to address the problem of mixed and contradictory findings in the literature. The results of the study show that: (1) The influence of gender and age on consumer willingness to purchase HFCVs cannot be judged. (2) Education, individual income, household income, family car number, driving range, knowledge, fuel availability, hydrogen refueling station density, environmental impact, policy incentives and attitudes all have a positive effect on HFCV adoption. (3) Household size, purchase price, fuel cost, maintenance cost and refueling time have a negative effect on HFCV adoption. (4) The purchase price, knowledge, fueling time, hydrogen refueling station density, and policy incentives significantly influence HFCV adoption. This paper provides new research methods and perspectives for the HFCV field and presents theoretical references for future governmental promotion of HFCV. • Meta-analysis of 24 studies conducted for consumers' intention to purchase HFCVs. • Subgroup analysis provides evidence of heterogeneity among estimates. • Household size and the other 4 influencing factors inhibit HFCV adoption. • Education and the other 9 influencing factors promote HFCV adoption. • The purchase price and other 4 influencing factors significantly influence HFCV adoption. [ABSTRACT FROM AUTHOR]

Implicit finite difference method is popular numerical method for simulation of transient pipeline dynamics, governed by the system of Euler partial differential equations. If advection equation is included in the mathematical formulation, gas composition tracking is also possible. If implicit scheme is used for gas composition tracking, simulated concentration profiles are distorted due to the occurrence of numerical diffusion, a non-physical phenomenon, caused by the 1st order accurate numerical implicit scheme. Intensity of the numerical diffusion can be decreased by use of θ -scheme with arbitrarily chosen implicitness. In order to evaluate accuracy of such numerical scheme and adequacy for usage in actual application, numerical model must be evaluated on actual gas pipeline system topology with actual measured boundary conditions and compared to actual measured results. Aim of this paper is to assess whether hydrogen concentration tracking is feasible using such approach considering complex grid topologies. Paper highlights the peculiarities of the proposed θ -scheme and finite difference method and its impact on the calculated concentration profile for binary gas mixtures. Non-physical flow reversal issue and its impacts on concentration tracking in looped pipeline system is researched and explained. Simulation results shows high accuracy for simulated values of hydraulic variables compared to the measured values, in some cases fit is perfect. Discrepancy between measured and the simulated values of the pressures at nodes on the main transport route is negligible, while the discrepancy increases with the distance from the main transport routes. The largest discrepancy occurred on the most distant node and was between 1.7006 bar (4.85%) and 1.7119 bar (4.88%), depending on the θ value. On the other hand, simulated concentration profile lacks finer details due to the numerical diffusion effects while the simulated concentration profile lags the measured profile, partly by the impacts of the 1st order accurate scheme and partly by effects of non-physical reversed flows. Discrepancy between simulated and measured amplitude of the tracked concentration profile was negligible, while discrepancy due to the time delay of the simulated and measured profile was more expressed and ranged between 2h to 9h. Largest time delay was caused by the non-physical flow reversal. • Model validation on actual network topology using measured boundary conditions. • Only gas component concentration profiles are affected by implicitness of the numerical scheme. • Simulation with lower implicitness is more accurate than fully implicit model. • Non-physical simulated flow reversal can occur in looped network topology and affect hydrogen concentration profile. [ABSTRACT FROM AUTHOR]

The objective of this paper is to evaluate and assess the potential of green hydrogen (H 2) as a substitute fuel for Cameroon's road transportation system. To achieve this objective, we start by providing a status quo of Cameroon's road transport. Then, we conduct an empirical analysis on the potential of H 2 as a fuel for vehicles. Based on photovoltaic electrolysis, we estimate the amount of H 2 needed to fuel vehicles with the associated costs as well as the quantity of carbon emissions that could be reduced in the event of an energy switch over the period 2020–2035. Finally, techno-economic indicators are used to assess the cost-effectiveness of an H 2 vehicle in comparison to a petrol car. Results reveal that if a transition were to take place before 2035 the Cameroonian road transport sector would need between 1.75 MT and 2.5 MT of H 2 fuel per year. With this transition, Cameroon could reduce its emissions by around 26% (or 429 megatons of CO 2 equivalent). Hydrogen-fuelled vehicles offer the greatest potential for initiating this transition with the current level of technology. Indeed, starting from an investment cost for PV of 0.42 USD/Wp, H 2 in a hydrogen-fuelled vehicle can be cost-effective compared with petrol in an internal combustion engine with a PV efficiency of 40%. Therefore, a hydrogen fuel-based transport sector could emerge through technological and production advances. This study contributes to solving the problems related to fossil fuel availability and greenhouse gas emissions arising from the expansion of the road transport sector in Cameroon, envisaging H 2 as an alternative fuel. • The situation of Cameroon's vehicle fleet and its expansion are thoroughly examined. • The challenges of alternative fuels are discussed with highlights on car technologies. • The cost of producing H 2 with photovoltaic electrolysis is also studied in this paper. • Cameroon's road transport would need between 1.75 MT and 2.5 MT of H2 fuel per year. • An H 2 transport sector could emerge through technological and production advances. [ABSTRACT FROM AUTHOR]

Explosion and deflagration may occur when a fuel cell truck in driving has hydrogen leakage faults, and the complex and changeable operating conditions of the vehicle are incredibly unfavorable for fault diagnosis. Therefore, to provide real-time diagnosis on the hydrogen supply system of driving truck, a diagnosis method of hydrogen leakage faults classification based on data-driven in this paper. The faults are divided into 3 levels using the K-means algorithm, and 4 features are selected as the hydrogen leakage faults diagnosis indicators. The Principal Component Analysis (PCA) method is used to reduce the dimensions of the data, while Support Vector Machine (SVM) is used for hydrogen leakage faults diagnosis. Meanwhile, the kernel parameter σ and the penalty factor C of SVM are optimized by Sparrow Search Algorithm (SSA) to improve diagnostic accuracy. The results show that the diagnostic accuracy of the SSA-PCA-SVM method proposed in this paper is higher than that of the ordinary SVM and PCA-SVM diagnosis methods when σ = 9.79, C = 7.89, which is over 97 %. • A classification diagnostic method is proposed for hydrogen leakage faults. • The diagnostic method can perform real-time faults diagnosis for driving truck. • The fault diagnosis accuracy of the proposed SSA-PCA-SVM method exceeds 97 %. [ABSTRACT FROM AUTHOR]

Hydrogen production from renewable energy sources is one of the important means to solve the world energy crisis. In the past decades, many experts and scholars have made different reviews on electrolyser and hydrogen production power supply. However, few articles have reviewed the actual industrial products of electrolyser and hydrogen production power supply from the perspective of industry. Therefore, this paper reviews the hydrogen production power supply and electrolyser used in practical engineering projects. It is helpful for experts and scholars to understand the development status of hydrogen production power and electrolyser in the industry and to further develop industrial products more suitable for practical applications. • This paper reviews the products of electrolyzers and hydrogen power sources. • This paper expounds the development situation of hydrogen production key products. • This paper summarizes the future development direction of water electrolysis. • This paper helps scholars to propose methods with practical significance. • This paper has guiding value for industrial equipment selection. [ABSTRACT FROM AUTHOR]

The integration of water electrolysis with renewable energy sources (RESs) constitutes a milestone in the transition to neutral and sustainable energy systems. The attractive features of the Proton Exchange Membrane (PEM) electrolyzer such as high purity of hydrogen, operation with high pressure, and high current densities have made it a critical technology to produce green hydrogen from RESs. Accurate models are required for proper design, analysis, and control of the electrolyzer when connected to the grid or renewable energy systems. Amongst the various types of models proposed for modeling the PEM electrolyzer, electrical circuit models are the easiest, most appealing, and straightforward to use for the investigation of electrolyzer operation and control. This paper presents an exhaustive review of the electrical circuit modeling reported in the literature on PEM electrolyzers. The reviewed models are classified analogously to the classifications of physical modeling in terms of voltage components (reversible, ohmic, activation, and concentration voltage drop), model behavior (static/dynamic), and modeling scale (cell/stack). Furthermore, MATLAB simulations of the reviewed models are implemented and the results are compared to pinpoint their similarities and deviations. Moreover, the applications, challenges, benefits, and drawbacks of the electrolyzer's electrical equivalent circuit modeling are discussed and overarching recommendations are set out for further research on the PEM electrolyzer modeling. The paper can be used as a comprehensive reference for choosing the appropriate electrical model of the electrolyzer for beginners as well as for research and industry experts who rely on PEM electrolyzer models in their work. • A comprehensive review of the electrical circuit models of the PEM electrolyzer is presented. • The models are classified in terms of voltage components, model behavior, and scale. • Simulations of the models are implemented to show their similarities and deviations. • Applications, benefits, and drawbacks of electrical circuit modeling are discussed. • Overarching technical recommendations are drawn for further research on electrical circuit modeling. [ABSTRACT FROM AUTHOR]

In this paper, the use of inhibitor for preventing the detonation propagation in the mixtures of hydrogen with air is studied in numerical experiments. The hydrocarbon propylene additive is used as an inhibitor. The paper presents the results of two-dimensional simulations of the cellular structure of a detonation wave. The dependence of cellular structure on the content of inhibitor is studied for different conditions of detonation initiation. The results allow determining critical content of inhibitor preventing from detonation onset. Experimental validation of results for hydrogen-air mixtures is provided. • Chemical methods for suppressing detonation in hydrogen-air mixture studied. • Numerical model for hydrogen-air mixture with propylene additive developed. • The effectiveness of hydrocarbon inhibitor for suppressing hydrogen-air detonation. • Comparison of simulation with experiment provide good agreement. [ABSTRACT FROM AUTHOR]