Hydrogen has the characteristics of high combustion value, no pollution of combustion products, and high element content, which is considered to be the most advantageous green energy in the future. The mobile hydrogen source can achieve the preparation of hydrogen at any time, effectively avoiding the safety hazards of hydrogen in the storage and transportation process. Magnesium-based active materials, which can release hydrogen by hydrolysis at room temperature, can be ideal materials for mobile hydrogen sources. This article presents a comprehensive review of recent research progress on magnesium-based active materials, focusing on four aspects of magnesium hydrolysis reaction research: preparation methods of magnesium materials, addition of catalysts, reaction media, and applications of active magnesium-based materials. In addition, the promotion mechanism of magnesium hydrolysis reaction for different preparation methods, catalysts, and reaction media is also summarized in detail. Finally, the limitations of the current research on magnesium-based active materials are analyzed, and the future research and application aspects of this material are prospected.

This study examines the phase equilibrium trends of the hydrolysis process in the thermochemical Cu–Cl cycle of hydrogen production. Various temperatures, pressures, and steam to copper ratios are modelled to predict CuCl2 conversion and progression of side reactions within the hydrolysis reactor. Novel reactor configurations, such as Moving Bed Reactors (MBRs), reactors in series and outlet gas recirculation are introduced within the analysis. Optimal conversion of CuCl2 and minimal by-product generation are obtained at a reactor temperature of 375 °C and pressure of 1 bar with improved conversion at higher temperatures and lower pressures. Improved reaction conversion is identified at higher steam to copper ratios. A 10:1 steam to copper ratio was used for the remaining reactor configuration scenarios. Reactors in series were simulated to mimic MBR behaviour. Three reactors in series with 10 kmol total steam consumption showed better conversion of 1 kmol of CuCl2 by 17% compared to a single reactor with the same steam inlet conditions. Mitigation of CuCl2 and Cu2OCl2 decomposition was also observed. The outlet gas recirculation improved the total desired product yield, however, the maximum conversion of CuCl2 was significantly impacted due to the high level of HCl concentrated steam. A combination of the gas outlet stream and reactors in series provide a method to improve the conversion rate. This reactor configuration is a challenging approach unless there is a separation technique to shift the reaction equilibrium or reduce HCl concentration within the gas stream.

Poor conductivity and low catalytic activity of NiFe layered double hydroxide (LDH) limit its application as an electrocatalyst for oxygen evolution reaction (OER). In this work, heterostructure along with oxygen vacancy and amorphous structure, which is available to the enhancement of catalytic activity were introduced in the surface of NiFe-LDH by Co and W codoping using hydrothermal method. The overpotential of OER at 50 mA cm−2 is decreased from 304 mV of NiFe-LDH to 263 mV of W0.5Co0.5@NiFe-LDH. Moreover, the existence of W6+ species in LDH can significantly improve the electrochemical kinetics of OER as well as the stability of catalyst. This work provides a new strategy to induce active sites in the surface as well as inhibit the formation of defects in the bulk so as to enhance the catalytic activity and still maintain the stability nature of catalysts.

Electrocatalytic water splitting is a promising solution to resolve the global energy crisis. Tuning the morphology and elemental composition is a crucial aspect in designing highly-efficient nanomaterials based electrocatalyst for water splitting. Herein, green synthesis using phytochemicals from aloe vera leaves extract was employed to hydrothermally synthesize copper oxide/cobalt oxide nanostructures on nickel foam. The reaction medium was performed in presence of mineralizers of different pH; hydrochloric acid (HCl), citric acid (CA), urea, diethyl amine (DEA) and sodium hydroxide (NaOH) to produce five different compositions of copper oxide/cobalt oxide on nickel foam. Based on FESEM and EDS analysis, it was verified that the plant mediated hydrothermal process yielded interesting morphologies and the elemental composition of the synthesized metal oxide nanostructures distinctly varied with effect to the different mineralizers used. Use of acidic mineralizers such as hydrochloric acid and citric acid favoured formation of copper oxide whereas basic mineralizers such as urea, diethyl amine and sodium hydroxide favoured formation of cobalt oxide. The green synthesis of metal oxide electrode in presence of urea exhibits the best OER electrocatalytic performance with an overpotential of 390 mV, and 453 mV for a current density of 50 mA cm−2 and 100 mA cm−2 respectively. The sample also exhibited sustained stability over 70 h, hence proving that the proposed electrode can serve as an efficient catalyst for electrocatalytic OER.

The field of ternary-based electrocatalyst design and fabrication has attracted considerable attention due to the unique physio-chemical and heterostructural properties exhibited by electrode materials in the realm of fuel generation. In this study, we present a straightforward method for efficiently constructing an electrocatalyst capable of facilitating the electrocatalytic splitting of H2O. Our approach involves the assembly of NiO nanoparticles onto MoS2 and BiVO4 using ultrasonication. Spectroscopic analysis reveals the presence of moderated electronic configurations resulting from a robust chemical interaction within the nanostructure. This interaction induces a charge shift from Ni2+ to Mo6+/Mo4+ across the interfacial Mo–S–Ni bond, leading to an increase in active sites and facilitating charge/mass transfers for the OER and HER within the nanostructures. Furthermore, the NiO/MoS2/BiVO4 nanostructure exhibits exceptional catalytic performance under alkaline conditions. It demonstrates a low overpotential of 300 mV for the OER and 95 mV at 10 mA cm−2 for the HER. Importantly, the nanostructured electrode maintains remarkable electrochemical stability for both HER and OER, as evidenced by minimal voltage fluctuations even after continuous operation for 24 h. This work highlights a simple yet significant strategy for optimizing electronic configurations using dual-functional transition metal-based electrocatalysts in the context of H2O splitting.

Proton exchange membrane electrolysis cells (PEMEC) can be utilized to produce hydrogen using renewable energy. In this paper, photovoltaic (PV) integrated with PEMEC is developed for hydrogen production. Based on the operation characteristics of PV and PEMEC, two operation strategies (Strategy 1 and Strategy 2) are proposed to regulate membrane temperature lower than 353.15 K under different solar irradiations. For Strategy 1, the water flow rate is firstly increased and then the inlet water temperature is reduced in the morning with increasing irradiation; and only increasing the inlet water temperature in the afternoon. While for Strategy 2, only reducing the inlet water temperature is adopted in the morning, and increasing the inlet water temperature in the afternoon. Results show that Strategy 1 outperforms Strategy 2 in terms of higher energy efficiency of 5.38% and exergy efficiency of 5.46%. However, the specific energy consumption is higher with Strategy 1 owing to higher pump power consumption, which is 6.15 kWh/Nm3.

Abstract not available

Technological innovation is important to further reduce the cost of hydrogen fuel cells (HFC) and enhance commercial availability. Technology patents hydrogen fuel cell play an important role in understanding the trend of technological innovation and future policymaking. By extracting patent data of hydrogen fuel cells from IncoPat database between 2003 and 2022, the knowledge map of hydrogen fuel cell technology was drawn in this paper based on the statistical analysis method and IPC co-category analysis method. The results shows that: (1) From the technology life cycle trajectory, 2003–2013 is the initial stage of hydrogen fuel cell technology, and 2014–2022 is the rapid development period of hydrogen fuel cells. (2) Through mapping the knowledge map of hotspots in the hydrogen fuel cell technology field using IPC co-category analysis, knowledge map shows 849 nodes and 6116 connected lines, and the network density is 0.017. (3) From the hydrogen fuel cell technology clustering map, a total of nine hot topics were formed in 2003–2022, namely H01M8/04089, C08J5/22, H01M4/88, H01M8/0228, H01M8/10, C25B1/04, G01N27/12, F04D29/58, F17C13/02. (4) 59 significant IPCs were placed in the hydrogen fuel cell technology domain from 2003 to 2022. Moreover, the hydrogen fuel cell technology evolution can be divided into three phases, 2003–2008, 2008–2018, and 2018–2022, respectively.

Underground Hydrogen Storage (UHS) in the subsurface is an alternative to overcome limitations associated with a fluctuating production of renewable energy sources. The excess energy produced can be converted to hydrogen and stored in porous media. Hydrogen is injected and produced from geological formations via wells. There are several concerns regarding the interactions of hydrogen with the different well components responsible for maintaining proper well integrity, such as cement. This experimental study investigates the interaction between molecular hydrogen and cement Class H by characterizing samples using different physical and chemical tests. Results showed samples exposed to molecular hydrogen exhibited a greater compressive strength in both the short and long terms. Porosity and permeability were found to be lower in samples exposed to molecular hydrogen. NMR distributions showed a reduction of larger pores and an increase of smaller pore spaces. Acoustic velocities showed an increase of Young's Modulus, Shear's Modulus and a slight decrease in Poisson's ratio. The compositional analysis demonstrated that hydrogen presence increases the amount of portlandite and ettringite formed. The crystalline needle-shaped structure observed in the SEM confirmed the presence of portlandite and ettringite within some of the larger pores. This experimental study showed that molecular hydrogen present could increase the formation of portlandite and ettringite, causing a shift in the porosity distribution increasing the mechanical strength of the cement.

Ceramic materials have good temperature and corrosion resistance, which is one of the ideal materials used in microchannel catalyst support for medium and high temperature catalytic reaction. Three-dimensional (3D) flow field structure is the most potential microchannel structure due to its high efficiency of mass and heat transfer. However, ceramic materials are hard and brittle, and the size of microchannel structures are small. It is a great challenge to construct a ceramic based microchannel catalyst support with a complex 3D flow field by traditional processing methods. In this paper, a 3D staggered flow field microchannel with the width of 450 μm and the depth of 1500 μm was designed and processed by diamond wire sawing. The mass and heat transfer properties of straight microchannel (SM), micro-column array (MA) and 3D staggered microchannel (3DSM) were compared by simulation. The effects of different windward angles (60°, 90° and 120°) on the performance of mass and heat transfer in 3D flow field were analyzed. The simulation results showed that the performance evaluation criteria (PEC) of 3DSM120° was 1.37, which meant better performance of heat and mass transfer than SM and MA. And the PEC of 3DSM structure was increased from 1.25 to 1.37 with the windward angle increasing from 60° to 120°. The pressure drop characteristics and hydrogen production performance of the microchannel catalyst support with different structures (SM, MA, 3DSM) were tested. The experimental results showed that the 3DSM had a good hydrogen production performance of methanol steam reforming (MSR) with the inlet flow rate of 1.5 ml/h at 300 °C. The methanol conversion rate was 99.43%, which was 15.41% and 6.20% higher than that of SM and MA, respectively, due to its better performance of mass and heat transfer.

The widespread use of unsustainable fossil fuels has caused serious damage to the ecological environment. The development of sustainable clean energy is urgent. Producing hydrogen by water electrolysis can effectively solve fossil energy shortage and environmental pollution issues. The preparation of inexpensive, efficient, and stable electrocatalytic hydrogen evolution electrode materials is the key to achieving the application of electrocatalytic hydrogen evolution. Herein, the amorphous nickel oxide/nickel foam (NiOx/NF) hydrogen evolution electrode was prepared by a simple one-step hydrothermal method with hydrogen peroxide as an oxidant. The amorphous leaf array structure of NiOx/NF electrode can enrich the surface composition and expose more catalytic active sites. Further, hydrogen peroxide etching can optimize the electronic structure of NiOx, and accelerate the electron migration. Thus, NiOx/NF displays excellent alkaline hydrogen evolution activity with the low over potentials of 70, 318 and 361 mV at 10, 500 and 1000 mA cm−2, respectively, leading to high performance in alkaline HER than those of reported Ni-based electrodes and even surpasses commercial Pt/C at high current density. Our work provides a new approach for developing inexpensive electrocatalysts with excellent alkaline hydrogen evolution activity and stability.

A cogeneration power plant based on a solid oxide fuel cell with an aluminum-hydrogen reactor in which hydrogen is obtained from aluminum and water in the presence of alkali is described. The efficiency of such a reactor is 43,7%. The fuel utilization rate at a power plant with an electric capacity of 10 kW is 42,3%. The electrical efficiency of the fuel cell is 77.2%, the proportion of hydrogen oxidized in the anode is 80.5%. The specific consumption of conventional fuel for the production of electric energy is 0.283 kg reference fuel/kW·h, and for the production of thermal energy 78.7 kg reference fuel/GJ.Specific indicators are higher compared to similar indicators for cogeneration power plants running on hydrocarbon fuel, but less than in the Russian energy system – 0.33 kg reference fuel/kW·h.

This study experimentally examines the effect of the addition of mixed gas (C2H6 + C2H4): (CO + H2) = 1:5 on the explosion characteristics of methane (volume fractions of 7%, 9.5%, and 11%) The explosion pressure, rate of increase in explosion pressure and time to reach the maximum explosion pressure are monitored. The mole fraction of radicals, sensitivity of CH4, and rate of production (ROP) are then calculated. The results show that the addition of mixed gas has the greatest impact on the explosion characteristics of the 7% methane mixture. For methane mixture of 7%, 9.5% and 11%, R1, R107 and R104, respectively, have the greatest impact on the methane sensitivity. The impact on the methane sensitivity in descending order is 7% > 9.5% > 11%. R1 (H + O2 = O + OH) was the most promoting and primary reaction for the consumption of O2 and the production of OH.

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.

In Mexico, diesel is the second most used fuel, representing 28% of the national consumption, being the largest greenhouse gas emitter. In this work, the diesel engine can run smoothly in dual combustion mode diesel fuel/oxyhydrogen gas (OH2G) because OH2G fed to the diesel engine is limited by the volume available in the combustion chamber; this allows the timing and pressure in the combustion chamber to be kept within the limits of the engine y a combustion without detonations was observed, the existing infrastructure is used, and the consumption of diesel and contaminants emissions could be reduced. This study shows the effects produced in the engine combustion chamber by the dual combustion process of diesel fuel/oxyhydrogen after 500 h of operation. Two air-cooled mono-cylinder diesel engines with a displacement of 405 cm3 were operated; a D100 engine was operated with 100% diesel and OH210 engine in dual combustion (diesel fuel/oxyhydrogen) was operated. Both engines were maintained at 40% load with respect to their maximum power during 500 h OH2G was generated in situ by alkaline electrolysis, and a flow of 2 sL min-1 was fed through the intake port during the suction stroke of the engine. Visual analysis, weight and dimensions of the engine parts, metallographic analysis, oil analysis, and electrolyte drag were used to determine the effects on the component materials. For the engine with dual combustion, diesel fuel/oxyhydrogen, was no structural damage to the engine components, although a slight corrosion onset was observed in some components, such as the piston ring. Moreover, iron and aluminum in the oil were off-standard, which is attributed to the corrosion processes occurring because of water steam containing electrolyte traces being fed to the engine with the oxyhydrogen gas. This implies that more oil changes are necessary within a short period. Therefore, a more robust gas purification process will be implemented, and the injection system will be optimized.

In the present study, techno-economic-environmental optimization of a solar-boosted energy system generating power, freshwater, and methanol as a promising clean fuel has been undertaken. A heliostat field with variable mirrors is used in a gas turbine cycle to decrease the necessity of burning much hydrocarbon fuel. By using pressure swing adsorption, 80% of the contained carbon dioxide of the exiting stream of the gas turbine is recovered and stored. In addition, by exploiting the waste heat of the exiting stream of the gas turbine, an organic Rankin cycle, a multi-effect distillation with thermal vapor compression, and a single effect absorption chiller are driven. Furthermore, a proton exchange membrane electrolyzer is utilized to generate hydrogen and portions of stored hydrogen and carbon dioxide go through the methanol synthesis reaction to produce desired methanol. A comprehensive parametric study through the 4E analysis has been carried out to detect the influential design parameters to set the decision variables for the optimization process. In the end, due to the complexity of the system, a deep neural network is developed to lower the computational time. The findings of the deep neural network-based optimization show the optimal solution in which the total cost rate of the system, exergy efficiency, and the emitted carbon dioxide values are 1.26 $/s, 46.25%, and 0.58 kg/s, respectively.

Electrooxidation conversion of benzyl alcohol to value-added benzoic acid is a sustainable and environmentally method to acquire valuable chemicals and accelerate hydrogen production. However, this promising approach is limited by the expensive and less stable anode electrocatalysts and low current density at moderate cell potential. To address these challenge, herein, we develop hierarchical ZnCo2O4@Ni(OH)2 heterostructure nanoarrays on nickel foam (ZnCo2O4@Ni(OH)2/NF) for electrooxidation of benzoic alcohol coupled with hydrogen production. The as-prepared ZnCo2O4@Ni(OH)2/NF anode shows it excellent electrooxidation activity for benzyl alcohol to benzoate in 1.0 M KOH electrolyte with 0.1 M benzyl alcohol. At a constant potential of 1.62 V vs. RHE, the corresponding production rate of benzoate and H2 is 1.99 mmol cm−2 h−1 and 44.66 mL cm−2 h−1, respectively. In addition, the current density can reach 100 mA cm−2 only applying a potential of 1.48 V (vs. RHE). Above all, it exhibits high conversion of 99% and Faradaic efficiency (FE) of 96% for value-added benzoate. Moreover, it could be recycled at least eight times with stable electrocatalytic activity.

(La,Sr)CoO3 and (La,Sr)2CoO4 dual phase powders were synthesized via thermal plasma to be used as cathodes for intermediate temperature solid oxide fuel cells (IT-SOFC). This covered pure (La,Sr)CoO3 as well as the composites where the fraction of (La,Sr)2CoO4 was gradually increased reaching the mid-composition. Powders, all synthesized in the same condition, were extremely small in size, especially at mid-composition where they were close to 30 nm in size. Area specific resistance (ASR) determined from the symmetric cell imply improved cathodic performance at the mid-composition. Taking ASR = 0.15 Ω∗cm2 as benchmark, it was found that the (La,Sr)CoO3: (La,Sr)2CoO4 = 0.53:0.47 cathode may be used at temperatures close 750 °C. Measurements taken from several runs however imply that the cathode performance was not stable and ASR values increases with cycling. This was attributed to the powder form of the cathode which would be expected to coarsen rapidly due to accelerated surface diffusion.

In this work, the new application of cooperation search algorithm (CSA) is addressed to extract the unknown solid oxide fuel cell (SOFC)'s parameters supported by investigating and testing the cell steady-state and dynamic performances. Primarily, the indefinite SOFC's parameters are estimated utilizing CSA and the results are assessed and verified with compulsory comparisons. The minimum errors are obtained, CSA convergence behavior and SOFC's performance are all compared with other recognized algorithms in the literature. At last, and for more validations, the dynamic behavior of the SOFCs is studied when supplying electric vehicle (EV) operated with four DC motors at different speeds. The SOFCs and EV are represented via Simulink/MATLAB package. The EV's input current, voltage, power, and torque are traced at various acceleration and speed according to the road nature and/or driver requirements. The extensive investigations and validations prove the high efficacy of CSA capabilities in representing the SOFCs and for analyzing their steady-state and dynamic behaviors.

Using off-site hydrogen can reduce CO2 emissions from urban buildings with limited renewable energy generation. We demonstrated the supply and usage of off-site green hydrogen using a pilot-scale hydrogen energy utilization system, Hydro Q-BiC®, for a commercial building. The off-site location supplied green hydrogen to the on-site system using high-pressure gas. By developing rapid-filling-type metal hydride tanks, we could safely fill 100 Nm3 of off-site hydrogen at <1 MPaG in approximately 1 h. The use of off-site green hydrogen in a 24 h operation of Hydro Q-BiC® can extend the operation time of fuel cells and significantly contribute to a reduction in CO2 emissions. Estimations indicate that gray hydrogen increases CO2 emissions, and CO2 emissions can be reduced to zero using a green-hydrogen supply of 300 Nm3. The results indicate that the type and quantity of supply of off-site hydrogen are important for reducing the CO2 emissions of buildings.