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Polymer membrane electrolyzers are a useful tool for producing hydrogen, which is a renewable energy source. Unmanned aerial vehicle (UAV) fuel cells can be powered by the hydrogen and oxygen produced by the electrolyzer. The primary losses of polymer membrane electrolyzers must therefore be identified in order to maximize their performance. A renewable-based multi-energy system considers power, cooling, heating, and hydrogen energy as utility systems for integrated sport buildings. In this study, we investigate the effect of radiation intensity, current density, and other performance factors on the rate of hydrogen production in water electrolysis using a polymer membrane electrolyzer in combination with a solar concentrator. The findings showed that a rise in hydrogen generation led to an increase in current density, which increased the electrolyzer's voltage and decreased its energy and exergy efficiencies. The voltage was also increased, and the electrolyzer's efficiency was enhanced by a rise in temperature, a decrease in pressure, and a reduction in the thickness of the nafion membrane. Additionally, with a 145% increase in radiation intensity, hydrogen production increased by 110% while the electrolyzer's energy and exergy efficiencies decreased by 13.8% as a result of the electrolyzer's high input electric current to hydrogen output ratio. [ABSTRACT FROM AUTHOR]

An atmospheric-pressure microwave plasma torch is employed to generate hydrogen by injecting methanol aerosols into the near afterglow region of a nitrogen microwave plasma. Two types of reaction chambers are proposed to study the influence of different boundary conditions of reaction chambers on hydrogen production by comparison. Fourier transformation infrared spectrometer and gas chromatography are used to measure and determine the hydrogen production rate, energy efficiency, and hydrogen yield. Also, the effects of conditions of methanol injection and discharge parameters on methanol decomposition are investigated, respectively. It is found that the active species originated from collision with the excited and ionized N2 in the high gas temperature in the plasma discharge plays an important role in the conversion of methanol to hydrogen. The gas flow pattern in the reaction chamber is closely related to boundary conditions and significantly affects the reaction time of methanol in it, which is analyzed with the software of computational fluid dynamics. The achievements of hydrogen production in our work are as follows: production rate up to 921 l/h, energy yield up to 371 l/kWh, and hydrogen yield up to 70%, respectively. Furthermore, the reaction mechanism is discussed in detail with respect to the formation of outlet products. [ABSTRACT FROM AUTHOR]

Small-sized fuel cell is an ideal and promising power source for portable devices due to its long-term electricity supply and free of CO 2 emission. However, its commercialization is obstructed by reliable hydrogen source, which should be non-corrosiveness, as compact as possible, stable and controllable high purity hydrogen supply. In this study, a novel in situ hydrogen production material Al/BiCl 3 /γ-Al 2 O 3 composite is synthesized, which exhibits high hydrogen yield, fast hydrogen production rate and outstanding storage stability. The hydrogen production performance of Al/BiCl 3 /γ-Al 2 O 3 can be adjusted by changing BiCl 3 :γ-Al 2 O 3 weight ratio, additive content and milling time. XRD and SEM results indicate that surface cracks, active surface and metal Bi produced in fabrication process lead to the high hydrolysis activity of Al/BiCl 3 /γ-Al 2 O 3. Mechanism analyses reveal that hydrogen production process is the results of pitting, microgalvanic effect and catalytic effect. Taking into account hydrogen production performance, capacity and cost, Al/5 wt%BiCl 3 /5 wt%γ-Al 2 O 3 milled for 2 h is a potential hydrogen production material, which can in situ supply hydrogen for small-sized fuel cell. [Display omitted] • A novel in situ hydrogen production material Al/BiCl 3 /γ-Al 2 O 3 was synthesized. • Al/BiCl 3 /γ-Al 2 O 3 has no induction time and high hydrogen production rate and yield. • Hydrolysis activity relies on BiCl 3 :γ-Al 2 O 3 ratio, additive content and milling time. • Al/BiCl 3 /γ-Al 2 O 3 composite exhibits excellent storage stability. • Pitting, microgalvanic effect and catalytic effect are the hydrolysis mechanisms. [ABSTRACT FROM AUTHOR]

Solar-driven water splitting for hydrogen production is a vital approach to mitigating the energy crisis and achieving carbon neutrality and peak carbon emissions. Cd 0.8 Mn 0.2 S holds significant potential for photocatalytic hydrogen evolution but faces severe challenges due to photogenerated carrier recombination. To address this, we employed ultrasonic self-assembly to tightly couple Cu 2 WS 4 nanosheets with Cd 0.8 Mn 0.2 S nanoparticles, forming an S-scheme heterojunction to reduce carrier recombination rates. In this configuration, Cd 0.8 Mn 0.2 S acts as the electron acceptor, and Cu 2 WS 4 serves as the electron donor. The Cd 0.8 Mn 0.2 S/Cu 2 WS 4 structure creates a closely spaced interface, providing the shortest transfer distance for electron migration. The S-scheme heterojunction strategy effectively suppresses the recombination of photogenerated carriers, promoting vectorial separation. Under 10 W white light irradiation, the Cd 0.8 Mn 0.2 S/Cu 2 WS 4 composite photocatalyst exhibited remarkable hydrogen evolution activity, with a hydrogen production rate of 39.83 mmol g−1 h−1. This S-scheme heterojunction strategy lays the foundation for the structural design and large-scale application of high-activity visible-light photocatalysts. • Recombination of photogenerated carriers is inhibited. • Facilitated vector separation of photogenerated carriers. • In situ irradiated XPS validates the S-scheme heterojunction charge transfer mechanism. [ABSTRACT FROM AUTHOR]

Cobalt-free La 0.5 Sr 0.5 Fe 0.9 Mo 0.1 O 3-δ (LSFM) oxide is particularly investigated as a durable and efficient oxygen electrode material for the reversible solid oxide cells (RSOCs) in this study. Pr 6 O 11 nano-catalysts are introduced into LSFM oxygen electrode as synergistic catalysts to enhance and optimize the electrode reactions. Results demonstrate an effectively promoted oxygen reduction and evolution reaction kinetics of the Pr 6 O 11 decorated LSFM electrode. Polarization resistances (R p) of LSFM electrode are dramatically reduced with the increasing Pr 6 O 11 nano-catalysts and the lowest R p of 0.039 Ω cm2 is obtained at 800 °C, which is ∼97% lower than that of the LSFM electrode. The Pr 6 O 11 decorated LSFM oxygen electrode also displays a superior durability under cyclic anodic and cathodic polarizations. Furthermore, both the maximum power density and electrolytic current density of the Pr 6 O 11 decorated cell are more than 2 times that of the LSFM cell. Results make clear reliability of the Pr 6 O 11 decorated LSFM to be a promising oxygen electrode for RSOCs. • LSFM is investigated as a durable and efficient oxygen electrode in RSOCs. • Surface-decoration with Pr 6 O 11 nano-catalysts can promote ORR and OER kinetics of LSFM oxygen electrode. • Pr 6 O 11 decorated oxygen electrode exhibit a superior durability under cyclic anodic and cathodic polarizations. • Both the fuel cell and electrolysis cell properties of Pr 6 O 11 decorated cell are more than 2 times that of the LSFM cell. [ABSTRACT FROM AUTHOR]

A one-step calcination method was employed to fabricate a new TiO 2 /g-C 3 N 4 (TCN) composite catalyst. The therein TiO 2 nanoparticles with good dispersion were synthesized through a sol-gel method and followed by additional heat treatment. The ultra-thin and flat g-C 3 N 4 (CN) nanosheets were synthesized by calcining a mixture of urea and melamine. The obtained TCN exhibited significantly excellent performance, especially when 3 wt% Pt was added and lactic acid (HL) was used as a sacrificial agent, achieving a rate of 32.5 mmol/h/g. This improvement can be attributed to the uniform dispersion of nano TiO 2 particles on g-C 3 N 4 , the flat ultra-thin layer structure of CN, and the constructed heterojunctions between two, which promote the separation of photogenerated electron-hole pairs. Measurements of PL and photocurrent response confirmed enhanced efficiency in interface charge separation and transfer. Additionally, it demonstrated lower internal resistance in EIS tests. Notably, owing to the piezoelectric properties of CN, when the reaction liquid was subjected to additional ultrasonic treatment, the hydrogen production rate further increased to 43.57 mmol/h/g and 2.9 mmol/h/g, respectively, in simulated sunlight and visible light response. The piezoelectric effect of CN induced by ultrasound regulated the bandgap width of the catalysts, broadening their response to visible light. [Display omitted] • Small TiO 2 nanoclusters with good dispersion combined with ultra-thin, flat g-C 3 N 4. • The obtained TiO 2 /g-C 3 N 4 exhibited boosting photocatalytic hydrogen. • H 2 yield rate is 33 mmol/h/g with lactic acid sacrificial agent and Pt-deposition. • Hydrogen yield rate raised to 43.57 mmol/h/g due to piezoelectric effect of C 3 N 4. • Piezoelectric effect caused by ultrasound affected the response to visible light. [ABSTRACT FROM AUTHOR]

Geothermal energy is utilized due to its sustainability and ability to provide a continuous low-emission source of heat, making it an ideal complement to the high-efficiency requirements of modern power plants. This study investigates a novel configuration coupling a solid oxide fuel cell-gas turbine unit with a dual-flash binary geothermal structure, enhanced by low-temperature electricity generation and hydrogen production subsystems. This configuration incorporates a regenerative steam Rankine cycle and a proton exchange membrane electrolyzer to achieve an efficient overall design. The setup is evaluated from thermodynamic and economic perspectives using a non-dominated sorting genetic algorithm-II for optimization. A complete parametric study assesses the sensitivity of critical variables. Multi-objective optimization is conducted across three scenarios considering exergy efficiency, hydrogen production rate, sum unit cost of products, and the payback period as objective functions. Results indicate an optimal exergy efficiency of 56.95% and a hydrogen production rate of 0.22 kg/h, with a product unit cost of $7.06/GJ and a payback period of 1.12 years. The parametric study underscores the significant impact of the number of solid oxide fuel cells and their existing density on key variables of the presented configuration. This study highlights the system's potential for efficient and economically feasible power and hydrogen production. • Investigating a novel geothermal-solid oxide fuel cell-gas turbine configuration. • Combining Rankine cycle and proton exchange membrane electrolyzer for higher efficiency. • Enhancing the thermodynamic and economic performances through multi heat recovery. • Achieving 56.95% exergy efficiency and 0.22 kg/h hydrogen production rate. • Achieving unit cost of $7.06/GJ and payback period of 1.12 years. [ABSTRACT FROM AUTHOR]

Creating and building an integrated system that consists of a storage tank, an electrolysis cell with many electrolyzer types, and a green hydrogen generator that produces clean, sustainable gas using solar photovoltaic (PV) energy and renewable energy sources. Three different electrolyzer modules with six, eleven, and twenty-one plates each were created locally and meant to be utilized in the production of green hydrogen. The hydrogen storage system's design was also created. It is clear that the maximum value of hydrogen production is recorded in the following ordered: KOH (5.5 L/min) > NaOH (1.2 L/min) > NaCl (0.7 L/min) > MgSO 4 (0.4 L/min). Also, sea water was used as electrolyte solution with different dilution 5, 10, 15, and 20% using a natural sea water sample collected from the Mediterranean Sea. It is found that 15% sea water dilution reaches the maximum value of H 2 production (3.4 L/min). Using distilled water and tap water, respectively, the volume of generated H 2 gas reached its maximum value of 8 L/min and 6.5 L/min at 0.4 mols of KOH. It was observed that with increased time durations (0–90 min), enhance the rate of hydrogen production to be reaches 8.2 and 11.5 L/min when using 0.05 and 0.1 mols KOH, respectively. This approach reduces environmental effect and operational costs, providing a sustainable solution to the water and energy problems. The integrated system for using solar energy and photovoltaic (PV) for hydrogen production used the storage H 2 as a source of energy to operate the small water desalination plant. [Display omitted] • Creation of three different electrolyzer modules with six, eleven, and twenty-one plates. • Electrolysis cell and a storage tank with many electrolyzers using solar energy used for H 2 production. • KOH, NaOH, NaCl, and MgSO 4 used as an electrolyte solutions for H 2 productions. • Different dilution of a natural sea water sample used as electrolyte solution. • Numerous variables were estimated in order to influence the production of green H 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-NiO@CNFs/ZnIn 2 S 4 -Vs was prepared by electrospinning and solvothermal methods. • The different photothermal conversion abilities of Ni and CNFs convert NIR into heat energy. • The hydrogen production rate of the best sample (0.9Ni-NiO@CNFs/ZIS-Vs) was as high as 29.16 mmol·g−1·h−1. • Under Vis-NIR conditions, the apparent activation energy (Ea) of 0.9Ni-NiO@CNFs/ZIS-Vs is as low as 9.28 kJ·mol−1. • The photothermal conversion efficiency of the 0.9Ni-NiO@CNFs/ZIS-Vs sample is 61.42%. Photothermal synergistic catalysis is a novel technology that converts energy. In this study, ZnIn 2 S 4 with S-vacancy (ZIS-Vs) is combined with Nickel, Nickle Oxide and Carbon Nanofiber aggregates (Ni-NiO@CNFs) to create a multi-interface coupled photocatalyst with double Schottky barrier, double channel and mixed photothermal conversion effect. Theoretical calculation confirms that the Gibbs free energy (ΔG *H) of the S-scheme heterojunction in the composite material is −0.07 eV, which is close to 0. This promotes the adsorption of H* and accelerates the formation of H 2. Internal photothermal catalysis is achieved by visible-near infrared (Vis-NIR, RT) irradiation. The internal photothermal catalytic hydrogen production rate of the best sample (0.9Ni-NiO@CNFs/ZIS-Vs) is as high as 17.24 mmol·g−1·h−1, and its photothermal conversion efficiency (η) is as high as 61.42 %. Its hydrogen production efficiency is 20.52 times that of ZIS-Vs (0.84 mmol·g−1·h−1) under visible light (Vis, RT) conditions. When the Vis-NIR light source is combined with external heating (75 ℃), the hydrogen production efficiency is further improved, and the hydrogen production efficiency (29.16 mmol·g−1·h−1) is 26.75 times that of ZIS-Vs (1.09 mmol·g−1·h−1, Vis-NIR, RT). Further analysis shows that the increase in hydrogen production resulted from the apparent activation energy (Ea) of the catalyst decreasing from 16.7 kJ·mol−1 to 9.28 kJ·mol−1. This study provides a valuable prototype for the design of an efficient photothermal synergistic catalytic system. [ABSTRACT FROM AUTHOR]

[Display omitted] In this study, a directional loading of cadmium sulfide (CdS) nanoparticles (NPs) was achieved on the opposite edges of nickel metal–organic framework (Ni-MOF) nanosheets (NSs) by adjusting the weight ratio of CdS NPs in the reaction process to produce effective visible light photocatalysts. The close contact between the zero-dimensional (0D) and two-dimensional (2D) regions and the matching positions of the bands promoted charge separation and heterojunction formation. The optimal CdS NPs loading of composite material was 40 wt%. At this ratio, CdS NPs grew primarily at the opposite edges of the Ni-MOF NSs rather than on their surfaces. When lactic acid was used as the sacrificial agent, the hydrogen production rate of the 40 %-CdS/Ni-MOF heterojunction under visible light irradiation was 19.6 mmol h−1 g−1, making a 20-fold enhancement compared to the original CdS NPs sample (1.0 mmol h−1 g−1). The charge carriers generated in CdS NPs were transferred to Ni-MOF NSs through heterojunctions, where Ni-MOF NSs also served as cocatalysts to improve hydrogen production. The combination of the two materials improved the light absorption ability. In particular, the 40 %-CdS/Ni-MOF heterojunction exhibited good photostability, effectively preventing the photocorrosion of CdS NPs. This study introduces an approach for constructing efficient and stable photocatalysts for visible light–driven photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

A series of M/NiCo-Ferrite (M: Pt, Pd, Ru, and Rh) nanoparticles were successfully synthesized, through a facile sol–gel auto-combustion followed by impregnation-reduction approach, as a catalyst for hydrogen generation from hydrolysis of NaBH4. All synthesized samples were characterized by XRD, N2 adsorption–desorption method, ICP-OES, FE-SEM, and EDX analysis. Compared to the other samples, it was observed that the Rh/NiCo-Ferrite sample exhibited higher particle distribution and surface area. To evaluate the hydrogen generation rate, the hydrolysis was carried out at a temperature of 35 °C, with an aqueous solution containing 5 wt.% NaBH4 and 3 wt.% NaOH. The experimental findings indicate that the Rh/NiCo-Ferrite sample exhibited a superior rate of hydrogen generation, with an average value of 11,667 mL/min.gcat, compared to the other samples studied. Enhanced catalytic properties may be responsible for its high activity. In addition, the activation energy of hydrolysis of sodium borohydride over the Rh/NiCo-Ferrite sample was 54.5 kJ/mol which is lower than the activation energy of many Ferrite-based catalysts. Moreover, the re-usability test of the Rh/NiCo-Ferrite sample denoted a decline in the catalytic activity after 4 recycling experiments due to the alterations in morphology and the reduction in the quantity of active phase. [ABSTRACT FROM AUTHOR]

The use of semiconductor‐based photocatalytic methods has been widespread for a range of applications, including pollution control and energy generation. However, certain analytical concerns limit the effectiveness of these photocatalysts, such as their limited light absorption capacity, physicochemical instability, and large energy band gap. To address these issues, scientists have been exploring integrating carbonaceous materials into photocatalytic systems to enhance their activity. This review focuses specifically on fullerene photocatalysts, a type of carbonaceous photocatalyst that has shown great promise in recent research. Fullerenes, which include C60 and C70, have unique properties that make them ideal for use as photocatalyst amplifiers in combination with other semiconductors or non‐semiconductors. This review summarizes recent research into the use of fullerene‐based materials for a variety of photocatalytic applications, including pollutant degradation, and hydrogen energy production. The efficacy of fullerene‐based photocatalysts is also discussed in recent breakthroughs in photocatalytic mechanisms and synthesis methods, focusing on pollution removal and hydrogen generation. Finally, the review addresses ongoing challenges and opportunities for fullerene‐based photocatalysts. The goal is to contribute to advancements in environmental protection and energy generation. [ABSTRACT FROM AUTHOR]

Platinum (Pt)‐based compounds are the benchmarked catalysts for hydrogen evolution reaction (HER) but exhibit slow kinetics in alkaline environments. The *OH accumulation on Pt surface can block active sites, affecting proton reduction and water re‐adsorption. Alloying Ruthenium (Ru) with Pt sites can significantly modulate the adsorption and desorption of water dissociation intermediates. Choosing suitable supports and utilizing metal‐support interaction (MSI) is crucial for active site optimization. PtRu alloy anchored on tungsten oxide (WO3) with rich oxygen vacancies (OV) is prepared through an ultrafast microwave‐assisted approach. Benefiting from the coupling effects between alloying and MSI, PtRu/WO3‐OV exhibits exceptionally high HER activity. In 1 m KOH, 1 m KOH + seawater, and 0.5 m H2SO4, it requires ultralow overpotentials of 9, 26, and 6 mV to achieve 10 mA cm−2, respectively. The designed catalyst surpasses commercial Pt/C in mass activity and demonstrates considerable potential for intermittent energy integration. Density functional theory reveals that alloying Ru with Pt sites significantly reduces the energy barrier of dissociating *OH, modulating blockage on the surface and then promoting the overall alkaline HER process. This study offers insights into the rapid synthesis of non‐carbon supported catalysts with Pt site modulation for alkaline hydrogen generation. [ABSTRACT FROM AUTHOR]

Ammonia borane (NH 3 BH 3) as a solid chemical hydrogen storage material with a high hydrogen content can be hydrolyzed under mild conditions to release hydrogen. In this work, Fe–Ni–B/Cu(OH) 2 –Cu foam was synthesized by combining in situ growth and electroless plating. Compared with the binary Fe–B/Cu(OH) 2 –Cu foam and Ni–B/Cu(OH) 2 –Cu foam prepared by the same method, the ternary Fe–Ni–B/Cu(OH) 2 –Cu foam has superior catalytic performance. The Fe–Ni–B/Cu(OH) 2 –Cu foam catalyst was able to achieve a maximum hydrogen production rate of 5.6 ml min−1 cm−2 at 298 K with an activation energy as low as 46.3 kJ mol−1. And more importantly, its catalytic efficiency has hardly decayed after ten cycles. These excellent properties are due to its low activation energy and the large specific surface, multi–site Cu(OH) 2 –Cu–foam carrier. [Display omitted] • Cu(OH) 2 nanowires were grown on the surface of Cu foam by in-situ oxidation. • Ni–Fe–B was supported on the Cu(OH) 2 –Cu foam by electroless deposition. • The HG rate of Fe–Ni–B/Cu(OH) 2 –Cu foam catalyst was 5.6 ml min−1 cm−2 at 298 K. • The activation energy of Fe–Ni–B/Cu(OH) 2 –Cu foam was as low as 46.3 kJ mol−1. • The Fe–Ni–B/Cu(OH) 2 –Cu foam catalyst has excellent cycling stability. [ABSTRACT FROM AUTHOR]

Hydrogen energy, recognized as a pivotal clean energy source, has attracted considerable attention in the realm of photocatalytic hydrogen production. Nevertheless, inorganic materials were difficult to regulate band gaps, resulting in limited photogenerated carrier rates. Additionally, organic materials frequently suffer from insufficient stability and a propensity for electron recombination. Therefore, fully utilizing the interface effect will become an important breakthrough for novel and efficient catalysts. Herein, hydroxylate covalent organic frameworks (H-COFs) were formed by direct synthesis method, in addition, titanium dioxide (TiO 2) was used as an inorganic substrate, and TiO 2 was transformed titanium acid under weakly acidic conditions, meanwhile, chloride covalent organic frameworks (C-COFs) growth on TiO 2 surface by interface effect when H-COFs were formed into C-COFs under titanium acid. The structure characteristics, photoelectric performance, bandgap width and stability of C-COFs/TiO 2 were confirmed through characterization analysis. C-COFs/TiO 2 exhibit strong stability, conjugation effects, electron deficiency effects, and catalytic efficiency. Hydrogen production rate up to 5598 μmol g−1 h−1 by C-COFs/TiO 2 as photocatalyst. C-COFs/TiO 2 lead to 161 times improvement in photocatalytic activity for TiO 2 and 3.6 times improvement in photocatalytic activity for H-COFs. The catalytic reaction mechanism was obtained by utilizing experimental data and DFT calculation. This synergistic integration of organic inorganic combined catalyst provides a foundational framework for advancing research into novel photocatalysts. [Display omitted] • Chloride COFs growth on TiO 2 surface by interface effect when H-COFs were formed into C-COFs under titanium acid. • C-COFs/TiO 2 catalysts with electronic transmission channel was synthesized for the first time. • C-COFs/TiO 2 exhibit strong stability, conjugation effects, electron deficiency effects, and catalytic efficiency. • The reaction mechanism can be proposed by experimental and DFT calculations. [ABSTRACT FROM AUTHOR]

Plastic waste entering the environment through landfilling or improper disposal poses substantial risks to ecosystems and human health. Photoreforming is emerging as a clean photocatalytic technology that degrades plastic waste to organic compounds while simultaneously producing hydrogen fuel. This study introduces high-pressure torsion (HPT), a severe plastic deformation (SPD) method, as an innovative technique to enhance the photoreforming of polypropylene (PP) plastic mixed with a brookite TiO 2 photocatalyst. Hydrogen production systematically increases with the number of HPT turns, accompanied by the formation of valuable small organic molecules. The enhancement in photocatalytic activity is attributed to strain-induced defect formation in both catalysts and plastics, as well as the creation of catalyst/plastic interphases that enhance charge carrier transport between inorganic and organic phases. These findings reveal a new functional application for SPD in energy conversion and sustainability. • High-pressure torsion (HPT) is used for the photodegradation of polypropylene plastic wastes. • Brookite TiO 2 is employed as a photocatalyst for the photodegradation. • Hydrogen production from plastic degradation increased with HPT processing. • This increase is due to strain-induced defects and catalyst/plastic interphase formation. [ABSTRACT FROM AUTHOR]

This study investigates carbon-nitrogen thin films as active materials in photocatalytic methanol reforming, addressing the need for eco-friendly fuels with minimal waste and non-metallic photocatalysts. Additionally, it explores the synthesis of these materials using plasma-enhanced chemical vapor deposition (PECVD) from acrylonitrile or acetonitrile. This area has limited prior attention in carbon-nitrogen materials synthesis, particularly with subsequent application in methanol reforming offering potential advancements in clean energy production. The aim is to develop effective, environmentally friendly sources of hydrogen, where photocatalysts play a crucial role. The studies involved also characterization for morphology, and chemical structure. The results confirmed the activity in hydrogen production through methanol reforming, achieving a promising rate of 82 ± 6 μmol h−1 cm−2. [Display omitted] • Facile preparation of carbon-nitrogen films by cold plasma. • Non-metallic carbon-nitrogen catalysts for hydrogen production. • Hydrogen production rate of 32–82 μmol h−1 cm−2 over studied materials. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen evolution has attracted tremendous interest as it offers a process for generation of green hydrogen based on solar radiation. But the process is extremely complex as many factors influence photocatalytic hydrogen evolution. While novel photocatalysts such as MOFs, perovskites, conjugated polymers, carbon-based materials, quantum dots, and others face challenges such as stability and scalability, semiconductor photocatalysts and cocatalysts such as TiO 2 /Pt, Ni–CdS, CdS/ZnO, CdS/ZnS have the advantages of simplicity in synthesis, stability, and scalability. Despite decades of research, challenges such as charge separation, spectrum usage, low hydrogen generation efficiency, photocatalyst stability and scalability persist. This review discusses what has been achieved so far in the domain of photocatalytic hydrogen evolution and presents a critical analysis of challenges to be addressed in developing a robust and practical photocatalytic hydrogen generation system based on efficiency of photocatalysts and their stability and the extreme importance of efficient reactor designs. [Display omitted] • Challenges associated with photocatalytic hydrogen generation systems. • Photocatalysts, cocatalysts and their stability challenges in hydrogen evolution. • Potential of semiconductor nanostructures, plasmonic nanoparticles and QDs. • Importance of reactor designs in enhancing photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

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

Transition metal dichalcogenides (TMDs) have garnered attention as potential catalysts for water splitting owing to their unique structures, diverse electronic properties, and composition from earth‐abundant elements. While certain TMD catalysts, notably MoS2, have shown promising activity for hydrogen evolution reactions (HER), achieving performance comparable to traditional platinum catalysts remains a challenge. While significant effort has been invested into understanding the effect of TMD's structural properties, such as defectiveness and crystalline phases, recent work has emphasized the role of extrinsic factors on HER. This review summarizes the current understanding of the impact of commonly overlooked electrocatalytic effects that exhibit an enhanced importance in TMD‐based HER. By combining recent advances in theoretical modeling and experimental work, we review the dominating effects of extrinsic factors including electronic resistance, interfacial barriers, surface roughness, oxidation, and valence impurities. Our work aims to provide insights into optimizing TMDs as highly efficient catalysts for HER, facilitating future advancements in hydrogen generation technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoAl 1-x B MBene is demonstrated to be a robust support for loading Ru nanoparticles. • Ru/MoAl 1-x B achieves the superior catalytic performance towards hydrogen generation. • Mechanism of AB hydrolysis over Ru/MoAl 1-x B is systematically investigated. • This is a first example to demonstrate MBene for boosting AB hydrolysis. The coordination between carrier and active metal is critical to the catalytic efficiency of ammonia borane (AB) hydrolysis reaction. In the present study, we report a new type of catalytic support based on molybdenum boride (MBene) MoAl 1-x B and demonstrate that the effective combination of MoAl 1-x B with Ru nanoparticles can realize the significantly enhanced performance for hydrogen generation. Owing to the efficient activation and dissociation of reactants, the optimal Ru/MoAl 1-x B catalyst achieves the large turnover frequency of 494 mol H2 mol Ru -1 min−1, high hydrogen generation rate of 119817 mL min−1 g Ru -1 and favorable apparent activation energy of 39.2 kJ mol−1 for the catalytic hydrolysis of AB under alkaline-free condition. The isotopic test suggests the cleavage of O H bond in H 2 O is the rate-determining step for hydrolysis reaction, while the fracture of B–H bond in AB is also well revealed by attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy. Significantly, the flexible on-demand hydrogen generation is achieved by using chemical switches for on–off AB hydrolysis. This study provides a new support platform based on two-dimensional MBene to exploit efficient catalysts to boost AB dehydrogenation. [ABSTRACT FROM AUTHOR]

[Display omitted] Phase junctions exhibit great potential in photocatalytic energy conversion, yet the narrow light response region and inefficient charge transfer limit their photocatalytic performance. Herein, an anatase/rutile phase junction modified by plasmonic TiN and oxygen vacancies (TiN/(A-R-TiO 2 -Ov)) is prepared through an in-situ thermal transformation from TiN for efficient photothermal-assisted photocatalytic hydrogen production for the first time. The content of TiN, oxygen vacancies, and phase components in TiN/(A-R-TiO 2 -Ov) hybrids can be well-adjusted by tuning the heating time. The as-prepared photocatalysts display a large specific area and wide light absorption due to the synergistic effect of plasmonic excitation, oxygen vacancies, and bandgap excitations. Meanwhile, the multi-interfaces between TiN, anatase, and rutile provide built-in electric fields for efficient separation of photoinduced carriers and hot electron injection via ohmic contact and type-Ⅱ band arrangement. As a result, the TiN/(A-R-TiO 2 -Ov) photocatalyst shows an excellent photocatalytic hydrogen generation rate of 15.07 mmol/g/h, which is 20.6 times higher than that of titanium dioxide P25. Moreover, temperature-dependent photocatalytic tests reveal that the excellent photothermal conversion caused by plasmonic heating and crystal lattice vibrations in TiN/(A-R-TiO 2 -Ov) has about 25 % enhancement in photocatalysis (18.84 mmol/g/h). This work provides new inspiration for developing high-performance photocatalysts by optimizing charge transfer and photothermal conversion. [ABSTRACT FROM AUTHOR]

Y-shaped AuCu tripods with three-fold symmetry from icosahedral seeds and star-shaped AuCu pentapods with five-fold symmetry from decahedral seeds are controlled synthesized. CdS nanocrystals and carrier-selective blocking layer of Ag 2 S are selectively deposited onto the sharp tips of AuCu tripods for achieving effective charge separation in AuCu-Ag 2 S-CdS nanohybrids with an optimized hydrogen evolution rate of 2182 μmol·g−1·h−1. [Display omitted] Anisotropic nanostructures with tunable optical properties induced by controllable size and symmetry have attracted much attention in many applications. Herein, we report a controlled synthesis of symmetrically branched AuCu alloyed nanocrystals. By varying Au:Cu atom ratio in precursor, Y-shaped tripods with three-fold symmetry and star-shaped pentapods with five-fold symmetry are synthesized, respectively. The growth mechanism of AuCu tripods from icosahedral seeds and AuCu pentapods from decahedral seeds is revealed. Aiming to excellent photocatalytic performance, CdS nanocrystals are controlled grown onto the sharp tips of AuCu tripods and pentapods. In addition, a carrier-selective blocking layer of Ag 2 S is introduced between AuCu and CdS, for achieving effective charge separation in AuCu-Ag 2 S-CdS nanohybrids. Through evaluating the photocatalytic performance by hydrogen generation experiments, the AuCu-Ag 2 S-CdS tripod nanocrystals exhibit an optimized hydrogen evolution rate of 2182 μmol·g−1·h−1. These findings will contribute greatly to the understanding of complex nanoparticle growth mechanism and provide a strategy for the design of anisotropic nanoalloys for widely photocatalytic applications. [ABSTRACT FROM AUTHOR]

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

g-C3N4 emerges as a promising metal-free semiconductor photocatalyst due to its cost-effectiveness, facile synthesis, suitable visible light response, and robust thermal stability. However, its practical application in photocatalytic hydrogen evolution reaction (HER) is impeded by rapid carrier recombination and limited light absorption capacity. In this study, we successfully develop a novel g-C3N4-based step-scheme (S-scheme) heterojunction comprising two-dimensional (2D) sulfur-doped g-C3N4 nanosheets (SCN) and one-dimensional (1D) FeCo2O4 nanorods (FeCo2O4), demonstrating enhanced photocatalytic HER activity. The engineered SCN/FeCo2O4 S-scheme heterojunction features a well-defined 2D/1D heterogeneous interface facilitating directed interfacial electron transfer from FeCo2O4 to SCN, driven by the lower Fermi level of SCN compared to FeCo2O4. This establishment of electron-interacting 2D/1D S-scheme heterojunction not only facilitates the separation and migration of photogenerated carriers, but also enhances visible-light absorption and mitigates electron-hole pair recombination. Band structure analysis and density functional theory calculations corroborate that the carrier migration in the SCN/FeCo2O4 photocatalyst adheres to a typical S-scheme heterojunction mechanism, effectively retaining highly reactive photogenerated electrons. Consequently, the optimized SCN/FeCo2O4 heterojunction exhibits a substantially high hydrogen production rate of 6303.5 µmol·g−1·h−1 under visible light excitation, which is 2.4 times higher than that of the SCN. Furthermore, the conjecture of the S-scheme mechanism is confirmed by in situ XPS measurement. The 2D/1D S-scheme heterojunction established in this study provides valuable insights into the development of high-efficiency carbon-based catalysts for diverse energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

Enhancement of the light-absorption response and utilization of the photogenerated carriers represent a robust strategy for the design of high-performance photocatalyst. In this work, grafting CoxP nanoclusters onto S-scheme heterojunction of W18O49/ZnIn2S4 (WO/ZIS-CoxP) with strong response to the ultraviolet–visible–near infrared ray (UV–vis–NIR) region has been achieved, which possesses efficient electron-transfer-channel, and boosts charge-separation and transport kinetics. The as-prepared WO/ZIS-CoxP yields an impressive solar-driven hydrogen production rate of 45 mmol·g−1·h−1. The increased photocatalytic performance is attributed to the synergistic effect of the composite catalyst: (1) The local surface plasmon resonance-induced "hot electron" injection of W18O49 significantly increases the electron density; (2) the engineered S-scheme directional electron transfer promotes charge separation and enhances the reducing capability of photoexcited electrons; and (3) CoxP as electron-trap site for accelerating surface proton reduction reaction. This work provides a platform to impart nonprecious co-catalyst for engineering S-scheme heterojunction, serving a class of efficient solar-driven photocatalyst towards hydrogen production. [ABSTRACT FROM AUTHOR]

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

Development of the interfacial catalyst layer (IL) of a bipolar membrane (BPM) for its application in a water electrolyzer is carried out. Zirconium-oxide based three different metal-organic frameworks (MOFs: MOF-808, UIO-66, and Fe-MOF (dual metal)) were synthesized and separately incorporated as water-splitting IL to achieve three different BPMs. Catalytic activity of each BPM was separately evaluated and BPM with double metal clustered, Fe-based MOF (Fe-MOF) showed significantly higher water splitting performance compared to the other two containing single metal clustered (Zr) MOF. Subsequently, the catalyst loading at the interface layer was varied between 0.05, 0.2, 0.5, 1.0, and 2.0 mg∙cm−2, and BPMs with each composition were synthesized. The BPM with 1.0 mg∙cm−2 of Fe-MOF content showed the lowest (ever reported) water dissociation potential at 0.66 V, and this was ∼12% lower than the BPM without interface (synthesized inhouse). The water splitting performances along with electrochemical impedance spectroscopy (EIS) analysis were estimated and compared among three different electrode assemblies (MEAs) containing 0, 0.5, 1.0 mg∙cm−2 of Fe-MOF as interface catalyst of the single cell electrolyzer. Hydrogen production rates were separately monitored varying current density range: 0–500 mA∙cm−2, and 1.45 L∙h−1 (highest) was noted with 500 mA∙cm−2 for the MEA containing 1.0 mg∙cm−2 of Fe-MOF. This investigation is believed to be useful for designing different MOFs as IL of BPM and electrolyzers. [Display omitted] • Zirconium-oxide-based MOFs were synthesized for the interface catalyst layer in BPM. • Loading of Fe-MOF at BPM interface was optimized based on BPM I–V characteristics. • Double metal cluster Fe-MOF exhibited the lowest WD potential ever recorded, in reversed bias BPM. • Performances of single-cell BPM water electrolyzer for hydrogen production were investigated. [ABSTRACT FROM AUTHOR]

The utilization of hydrogen as an energy carrier faces a challenge due to its limited presence in its pure form in the Earth's atmosphere, necessitating its extraction from various sources. Among hydrogen production methods, microwave-induced plasma molecular cracking shows promise as an alternative. This review explores how different operational parameters of a microwave-induced plasma system with gas-phase discharge impact hydrogen production performance. Performance indicators include hydrogen production rate, energy yield, and final hydrogen concentration. Parameters influencing hydrogen production encompass microwave power, gas flow rate, initial hydrogen concentration, steam addition, gas injection method, and plasma-forming gas type. Other vital system parameters are also discussed. Higher absorbed power leads to increased hydrogen production, albeit less efficiently. Elevated carrier gas flow rate reduces residence time, consequently lowering performance, while higher fuel gas flow rates enhance hydrogen production. Introducing steam can enhance indicators and reduce soot, and injecting fuel gas directly into the plasma torch tip yields optimal hydrogen production. Avoiding excessive power, fuel gas flow, or water vapor is important, as hydrogen saturation can limit further performance enhancement. • Microwave-induced plasma appears as a promising alternative for H 2 production. • Operational parameters' impacts on the system performance were analyzed. • Steam addition and gas injection methods' impacts on H 2 production were discussed. • Optimal practices for enhanced H 2 production were determined. [ABSTRACT FROM AUTHOR]

This study investigates the hydrodynamic behavior and mass transfer performance in water electrolysis within an alkaline solution (30% wt KOH). By using a glass electrolyzer with vertical stainless steel 304 electrodes spaced 20 mm apart, the research employs an optical flow method to analyze the velocity field of hydrogen bubbles. Image sequences captured by a CCD camera with a pixel resolution of 67.2 μm facilitate this analysis. The study focuses on the effect of current density, ranging from 33 to 650 A/m2. Experimental results demonstrate that the velocity distribution in most areas of the electrolyzer is primarily influenced by two asymmetric flow patterns caused by the buoyancy of hydrogen and oxygen bubble layers. Regions with lower depths exhibit increased velocity and vorticity fields, resulting in greater motion within the electrolyte. Conversely, at higher current densities, the average velocity decreases due to the expansion of dynamic areas. These complex flow structures significantly affect bubble dynamics, causing velocity fluctuations between the electrodes. The findings offer valuable insights into hydrogen bubbles' dynamics and transport phenomena within the electrolyzer, enhancing the understanding of bubble behavior in alkaline water electrolysis. • Hydrogen generation in electrolysis has been experimentally studied. • Experimental analysis of the velocity field and main characteristics of the flow field. • Velocity fluctuations and recirculation occur in electrolyte regions, influencing bubble dispersion and dynamics. • Current density significantly impacts bubble generation, dispersion, and dynamics. [ABSTRACT FROM AUTHOR]

In this study, ZnS/P-doped-MoS 2 (ZnS/P–MoS 2) composite was synthesized for the first time via in-situ precipitation approach, whereby P–MoS 2 flowers were decorated with ZnS nanoparticles. Compared to ZnS, composite has significantly wider range of visible light absorption region, lower recombination rate and large surface area. The photocatalytic activity was demonstrated by ZnS/5%P–MoS 2 (ZPM-2) composite with hydrogen (H 2) generation rate of 1.2306 mmolg−1h−1, 46.12% of benzyl alcohol (BA) to benzaldehyde (BAL) conversion with 98.30% selectivity and 98.52% brilliant green (BG) dye degradation in 40 min. The improved efficiency of the ZPM-2 composite ascribed to synergistic effect between P–MoS 2 and ZnS, which helps to lower the band gap of ZnS, shift absorption to the visible light region, promoting electron transfer and inhibit electron-hole recombination rate. Our study provides a new insight to develop novel photocatalyst for photocatalytic applications. • Synthesized ZnS/P-doped-MoS 2 photocatalyst with dual characteristics using in-situ precipitation method. • The UV light-active absorption edge of ZnS shifting toward the visible region. • The composite showed enhanced photocatalytic activity compare to ZnS and P–MoS 2. [ABSTRACT FROM AUTHOR]

Fluorescent carbon nanoparticles, also known as carbon quantum dots (CQDs), have piqued the interest of researchers due to their numerous uses in chemical sensing, biomedical imaging, nanotechnology, photovoltaics, LEDs, and hydrogen generation. Aside from their optical brilliance, CQDs have benefits like low toxicity, environmental friendliness, cost‐effectiveness, and ease of manufacture, with adjustable properties via surface passivation and functionalization. This review article goes over CQDs in‐depth, addressing synthesis advances, benefits, limits, various synthesis processes, and prospective hydrogen generation applications. While CQDs have photocatalytic properties, they confront a few challenges, including low quantum yields, spectrum limitations, photostability limitations, limited catalytic activity, scaling difficulties, and environmental issues. Thorough research is required to use CQDs in sustainable hydrogen generation. Despite obstacles, CQD research remains appealing, with transformational promise for a cleaner and more sustainable energy future through controlled synthesis approaches displaying CQDs' many uses. [ABSTRACT FROM AUTHOR]

Recently, lead halide perovskites have emerged as promising photoanode materials for efficient hydrogen production. However, the sluggish kinetics of the oxygen evolution reaction (OER) and interfacial defect‐mediated charge accumulation inevitably result in efficiency loss and degradation of perovskite photoanodes. Herein, a defect‐passivated electron transport layer‐based perovskite photoanode combined with a catalyst layer favorable is introduced for iodide oxidation reaction bearing a small thermodynamic barrier and rapid kinetics compared to OER for efficient solar fuel generation. The resulting perovskite photoanode revealed a saturated photocurrent density of 22.4 mA cm−2 at 0.3 V versus the reversible hydrogen electrode (VRHE) with an impressive onset potential of −0.2 VRHE as well as durability for 225 h in a neutral electrolyte. In addition, an unbiased hydrogen‐production device comprising a perovskite photoanode and Pt coil electrocatalyst is demonstrated, achieving a remarkable solar‐to‐chemical conversion efficiency of 11.45% and stable operation for 25 h. Moreover, a wireless artificial leaf‐structured device realizing solar‐driven hydrogen generation in natural sea water under outdoor sunlight is presented. [ABSTRACT FROM AUTHOR]

Modern civilization has been highly suffering from energy crisis and environmental pollutions. These two burning issues are directly and indirectly created from fossil fuel consumption and uncontrolled industrialization. The above critical issue can be solved through the proper utilization of green energy sources where no greenhouse gases will be generated upon burning of such materials. Hydrogen is the most eligible candidate for this purpose. Among various methods of hydrogen generation, electrocatalytic process is one of the most efficient methods because of easy handling and high efficiency. In these aspects Co‐based nanomaterials are considered to be extremely significant as they can be utilized as efficient, recyclable and ideal catalytic system. In this article a series of Co‐based nano‐electrocatalysts has been discussed with proper structure‐property relationship and their medium dependency. Therefore, such type of stimulating summary on recently reported electrocatalysts and their activity may be helpful for scientists of the corresponding field as well as for broader research communities. This can be inspiration for materials researchers to fabricate active catalysts for the production of hydrogen gas in room temperature. [ABSTRACT FROM AUTHOR]

The rapid advancement of refined nanostructures and nanotechnologies offers significant potential to boost research activities in hydrogen storage. Recent innovations in hydrogen storage have centered on nanostructured materials, highlighting their effectiveness in molecular hydrogen storage, chemical storage, and as nanoconfined hydride supports. Emphasizing the importance of exploring ultra‐high‐surface‐area nanoporous materials and metals, we advocate for their mechanical stability, rigidity, and high hydride loading capacities to enhance hydrogen storage efficiency. Despite the evident benefits of nanostructured materials in hydrogen storage, we also address the existing challenges and future research directions in this domain. Recent progress in creating intricate nanostructures has had a notable positive impact on the field of hydrogen storage, particularly in the realm of storing molecular hydrogen, where these nanostructured materials are primarily utilized. [ABSTRACT FROM AUTHOR]

The construction of heterojunctions is one of efficacious ways to improve the charge transfer and suppress the recombination of photoexcited electron-hole pairs for enhancing reactive activities of photocatalysts. Ternary NiS-ReS 2 /CdS composites are synthesized via a one-step hydrothermal method and the heterojunction nanostructures are achieved. The NiS-ReS 2 /CdS photocatalyst exhibits the superior photocatalytic activity with a hydrogen production rate up to 139 mmol g−1 h−1, which is much higher than binary composites and pure CdS. The contributions of the dual cocatalysts NiS and ReS 2 are verified to narrower bandgaps, lower resistances and increase photocurrent density of NiS-ReS 2 /CdS, promoting the absorption of visible light and the migration of photoinduced electrons. The NiS-ReS 2 /CdS heterostructures provide a possible dual Z-scheme path for the rapid transfer of electrons. The tailoring of the dual cocatalysts is effective to improve the photocatalytic hydrogen production. [Display omitted] • Ternary NiS-ReS 2 /CdS composites are fabricated via a one-step hydrothermal way. • NiS-ReS 2 /CdS exhibits the photocatalytic hydrogen production rate of 139 mmol g−1 h−1. • A suitable small amount of rhenium benefit to the high photocatalytic activity. • The heterostructures provide the dual Z-scheme paths to improve hydrogen production. [ABSTRACT FROM AUTHOR]

As demand for clean energy continues to increase, scientists are exploring alternative sources to fossil fuels, which are a major contributor to climate change. Hydrogen (H 2) has been identified as a promising solution due to its ability to be derived from water-splitting using electricity, solar, or thermal energies. Solar water-splitting is a conventional and eco-friendly approach for producing green H 2 with high energy storage capacity among various power sources. Perovskite (PSK) minerals have emerged as a popular choice for H 2 production due to their unique optoelectronic properties, including high carrier mobility, tunable bandgap, and strong light absorption. These properties make PSK materials suitable for perovskite-based H 2 generation processes, including photocatalytic, electrocatalytic, photo-electrocatalytic, and thermochemical processes for hydrogen generation. This investigation comprehensively overviews recent breakthroughs, challenges, and perspectives in PSK-based hydrogen generation systems. We discuss the reasons behind the selection of PSK materials, including their high efficiency, stability, and low cost, as well as opportunities to enhance their performance through material optimization and device engineering. Overall, PSK-based H 2 Evolution systems hold significant promise for addressing the pressing energy and environmental challenges of our time. [Display omitted] • Perovskite materials offer high efficiency & stability, driving green H 2 production. • Solar water-splitting with PSKs enables eco-friendly H 2 generation. • Tunable bandgap & strong light absorption make PSKs ideal for H 2 systems. • Material optimization & device engineering enhance perovskite-based H 2 evolution. [ABSTRACT FROM AUTHOR]

Among conventional hydrogen storage materials, LiBH 4 has been regarded as one of the best hydrogen transporters due to its relatively large hydrogen capacities. However, because of its extraordinarily high dehydrogenation temperatures, LiBH 4 was not suitable for hydrogen storage due to its stable thermodynamic features. Herein, we present a novel approach to LiBH 4 that uses solid-state multi-hydroxyl mannitol as a reactant, regulating hydrogen release below 69.9 °C. More than 7 wt% H 2 could be released with ultra-fast rates at 140 °C from the LiBH 4 -mannitol composite. XRD, FTIR, and SEM tests revealed that the reaction between mannitol (Hδ+) and LiBH 4 (Hδ−) to produce hydrogen was accompanied by the generation of large amounts of heat in situ, which further promoted the decomposition of LiBH 4 for hydrogen production, exceeding the theoretical dehydrogenation amount of Hδ+- Hδ− reaction. This work indicates possibilities for the development of fast and easy high-capacity hydrogen generation systems based on complex hydrides. The LiBH 4 -mannitol composites were prepared by ball-milling, and ultra-fast released 7.0 wt% hydrogen below 140 °C. Mannitol (Hδ+) reacted with LiBH 4 (Hδ−) to produce hydrogen was accompanied by the generation of large amounts of heat locally, which further promoted the decomposition of excess LiBH 4 for hydrogen production. [Display omitted] • More than 7 wt% H 2 could be ultra-fast released from LiBH 4 -mannitol composites below 140 °C. • Mannitol (Hδ+) reacted with LiBH 4 (Hδ−) to produce hydrogen. • The heat generated by dehydrogenation further promoted the decomposition of excess LiBH 4 nearby. [ABSTRACT FROM AUTHOR]

This work provides a new mathematical model of photovoltaic (PV) solar panels integrated with proton exchange membrane (PEM) water electrolyzer cells for optimal hydrogen production. The proposed mathematical model evaluates the operating temperature of the PV solar panel and PEM water electrolyzer and the effect of membrane thickness on hydrogen production performance. In the model results, when the operating temperature of the PEM water electrolyzer increased from 25 °C to 80 °C, the hydrogen flow rate of about 1.44 and 1.82 mL/min at 2 A/cm2, respectively. Moreover, the maximum flow rate of hydrogen produced in a 7-cell and 14-cell PV-assisted PEM water electrolyzer stack is around 349.98 mL/min and 699.91 mL/min, respectively. The total efficiency of the integrated PV-assisted PEM water electrolyzer stack is around 6.0–6.5%, depending on the solar irradiance values. This mathematical model significantly contributes to green hydrogen production using the integrated PV-assisted PEM water electrolyzer system. Moreover, the mathematical model of PV-assisted PEM water electrolyzer will be a pioneer in determining the hydrogen production potential of the PEM water electrolyzer systems. • Evaluation of a new mathematical model of hydrogen production with PV-assisted PEM water electrolyzer. • Mass transfer modeling for single-cell PEM water electrolyzer is presented. • The hydrogen production rate relies on solar irradiation, temperature, and membrane thickness. • The efficiencies of PEM water electrolyzer and PV module are ∼65.5% and ∼15.37%, respectively. • Total average hydrogen production with a PV-assisted PEM water electrolyzer is ∼9.970 mL/min. [ABSTRACT FROM AUTHOR]

In the quest for effective photocatalysts for hydrogen production via photocatalytic water splitting, ZnIn 2 S 4 has garnered considerable attention due to its high photocatalytic hydrogen evolution capability. In this study, boron-doped ZnIn 2 S 4 was successfully synthesized via a hydrothermal method, with a small amount of cobalt phosphate (Co-Pi) decorated on its surface. The hydrogen evolution rate of boron-doped ZnIn 2 S 4 was determined to be 5.2 mmol g−1 h−1, surpassing that of pure ZnIn 2 S 4 by 1.68 times. Moreover, with the addition of Co-Pi to boron-doped ZnIn 2 S 4 , the hydrogen production rate escalated to 29.7 mmol g−1 h−1, which is 9.58 times higher compared to pure ZnIn 2 S 4. UV–vis analysis revealed that boron doping introduced new energy levels into ZnIn 2 S 4 , effectively narrowing the bandgap and enhancing light absorption wavelength range. Furthermore, PL and XPS analyses indicate that Co-Pi effectively captures photogenerated holes (h+) in ZnIn 2 S 4 , retaining photogenerated electrons and overcoming the disadvantage of electron-hole pair recombination in ZnIn 2 S 4. The doping and loading of Co-Pi as a cocatalyst ultimately contribute to enhancing hydrogen production efficiency, thereby significantly improving the photocatalytic hydrogen evolution capability of ZnIn 2 S 4. This study provides a scalable idea for designing composite catalysts in which doping and co-catalysts work together. • ZnIn 2 S 4 (ZIS) was synthesized hydrothermally using ZnCl 2 , In(NO 3) 3 ·xH 2 O, and thioacetamide (TAA) as precursors. • Defective ZnIn 2 S 4 (B-ZIS) was hydrothermally synthesized from ZIS and NaBH 4. • B-ZIS-CP composites were prepared through the in situ photodeposition of cobalt phosphide (Co-Pi) onto B-ZIS. • The composite catalysts exhibited exceptional photocatalytic activity for hydrogen evolution. • B-ZIS-CP demonstrates remarkable separation efficiency of photogenerated electron-hole pairs. [ABSTRACT FROM AUTHOR]

In this study, a bimetallic Co–Fe nanocatalyst supported on carbon quantum dots (CQDs) is introduced as an effective catalyst for promoting hydrogen generation upon hydrolysis of sodium borohydride. Hydrothermal synthesis routes were used to produce CQDs support. All samples were subjected to analysis using XRD, UV–Vis, Raman, FTIR, FESEM, EDX, and nitrogen adsorption-desorption techniques. Benefiting from the higher surface area (51 m 2 g r ), pore volume (0.200 m L g r ), and good dispersion of Co–Fe nanoparticles over the CQDs support, the CoFe/CQD spherical nanocatalysts with 5 wt.% iron content exhibited the highest catalytic activity of 20200 mL/min.g cat within only 1 min of reaction. The kinetics studies revealed a low activation energy of 48 kJ/mol over this optimum catalyst. In addition, it was found that the catalytic performance of this catalyst was decreased after 4 runs of recycling experiments. Catalyst degradation and leaching of the active phase were likely responsible for the decline in catalyst performance. [Display omitted] • Bimetallic Co–Fe nanocatalysts supported on carbon quantum dots CQDs were prepared. • The prepared catalysts were used for H 2 generation upon hydrolysis of NaBH 4. • CoFe/CQD with 5 wt% iron exhibited superior performance in the hydrolysis of NaBH 4. • CoFe/CQD with 5 wt% iron possessed a high hydrogen generation, 20200 mL/min.g cat. • The activation energy (E a) of this reaction was 49.5 kJ/mol over CoFe/CQD with 5 wt% iron. [ABSTRACT FROM AUTHOR]

The development of efficient nanocomposites represents a promising strategy for enhancing the transfer and separation of photogenerated carriers within metal-organic frameworks (MOFs) for photocatalytic H 2 generation. In this study, we report, for the first time, the successful fabrication of a novel CuGaS 2 @NH 2 -MIL-125(Ti) nanocomposite in a two-step synthesis, consisting of octahedral NH 2 -MIL-125(Ti) metal-organic frameworks interspersed with flat hexagonal plates of CuGaS 2. The CuGaS 2 @NH 2 -MIL-125(Ti) nanocomposite effectively mitigates the recombination rate of photogenerated electron-hole pairs. Notably, the most active CuGaS 2 @NH 2 -MIL-125(Ti) composite (containing 30 wt% CuGaS 2) achieves a remarkable hydrogen generation rate of 965.07 μmol/g cat , surpassing the performance of NH 2 -MIL-125(Ti) and CuGaS 2 by approximately 83 and 144 times, respectively. Additionally, the apparent quantum efficiency for the most active material at a wavelength of 380 nm is 9.07%. This study provides valuable insights into the design of efficient I-III-VI2 compound-MOF nanocomposites for H 2 generation applications. [Display omitted] • NH 2 -MIL-125(Ti)/CuGaS 2 composites: novel dual-step synthesis. • Enhanced charge transfer in composite components boosted H 2 photoproduction. • Photocatalytic efficiency is directly related to CuGaS 2 content in the composite. • Investigation of the photocatalytic mechanism of H 2 generation via AQE analysis. [ABSTRACT FROM AUTHOR]

Enhancing the hydrolysis reaction of NaBH 4 for efficient hydrogen production requires the development of effective catalysts. In this study, the solution particles used for nanoparticles synthesized using the ultrasonic spray (US) method were produced for the first time in N 2 at room temperature in the gas and liquid intermediate phases. It also brings a new approach to synthesizing low-cost and efficient catalysts using ultrasonic spray technology. The proposed method involves US the CoCl 2 solution into the NaBH 4 solution to reduce cobalt, producing catalysts for hydrogenation. This innovative approach pioneers a gas-liquid interface reaction for metal reduction. The resulting catalysts were characterized using SEM, XRD, XPS, TEM, BET and FT-IR analysis. The influence of NaOH/NaBH 4 concentration, solution temperature, and catalyst amount on hydrogen production rate was investigated, and kinetic parameters were analyzed to understand the reaction kinetics better. The hydrogen production rates of US-Co and reduction method (RM) Co catalysts under the same conditions were calculated as 3995 ml H2 /min.g cat and 1245 ml H2 /min.g cat , respectively. The activation energy values calculated for the NaBH 4 hydrolysis of the US-Co catalyst using the nth-order and Langmuir-Hinshelwood kinetic models are 46.75 kJ/mol and 46.87 kJ/mol, respectively. Therefore, it can be concluded that the Langmuir-Hinshelwood kinetic model is consistent with the nth-order kinetic model. Experimental results showed that the ultrasonic spray method is very effective in producing active metal catalysts, offering promising opportunities for catalytic advances. [Display omitted] • A novel method of ultrasonic spray was improved for Co NPs pioneering a gas and liquid interface reaction. • The US-Co is highly active for NaBH 4 with an H 2 production rate of 3995 ml H2 /min.g cat at 30 °C. • The activation energy was calculated to be 46.75 kJ/mol with US-Co NPs. [ABSTRACT FROM AUTHOR]

For the effective operation of a Power-to-Hydrogen (P2H) system that integrates renewable energy sources with an Alkaline Water Electrolyzer (AWE), precise modeling of the AWE plant is paramount. This research delves into the electrothermal dynamics of the AWE and constructs an advanced Power–Temperature–Hydrogen (P–T–H) coupling model of the AWE plant. The developed model intricately captures the pivotal role of temperature in modulating hydrogen production rates, power constraints, and system flexibility. Furthermore, to enable the application of the model to system-level optimization, we undertake a rational simplification process to transform it into a linear model. Building upon this model, we devise an optimized power scheduling strategy for the P2H system that enhances the system's economic efficiency and adaptability. A comprehensive sensitivity analysis of crucial variables such as hydrogen demand, transmission line capacity, and AWE capacity underscores the strategic insights this model offers for system development and implementation. In a word, the developed P–T–H model is well feasible for the improvement of the system's operation with AWE. • The decisive role of temperature in hydrogen production properties, power limit, and operational flexibility of an AWE is demonstrated. • A novel P–T–H coupling model is proposed to capture temperature-based operation characteristics of the AWE plant. • Sensitivity analysis reveals the dependency of daily optimal revenue on hydrogen demand and transmission line capacity. [ABSTRACT FROM AUTHOR]

The proton exchange membrane water electrolysis system has long been considered a promising technique for the generation of hydrogen owing to its high electrolytic efficiency, reliability, and quick response to renewable energy sources. At present, noble metals and their oxides (e.g., Pt, IrO2, and RuO2) are widely used as high active electrocatalysts for accelerating the conversion efficiency of the water electrolysis process, especially in acidic media. Nevertheless, the scarcity and instability seriously impede their large‐scale application in practice. In the past years, metal‐organic frameworks (MOFs) have proven to be an ideal platform for designing efficient and cost‐effective electrodes due to their unique physicochemical properties. In this review, the fundamental catalytic mechanisms of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in acidic media are discussed first. Then, design strategies and advanced characterizations for MOF‐based water‐splitting catalysts are summarized. Finally, the recent research advances of MOF‐based electrocatalysts for HER and OER in acidic electrolytes, along with current challenges and future opportunities, are provided. [ABSTRACT FROM AUTHOR]

Photoactive artificial nanocatalysts that mimic natural photoenergy systems can yield clean and renewable energy. However, their poor photoabsorption capability and disfavored photogenic electron–hole recombination hinder their production. Herein, we designed two nanocatalysts with various microstructures by combining the tailored self-assembly of the meso-tetra(p-hydroxyphenyl) porphine photosensitizer with the growth of titanium dioxide (TiO2). The porphyrin photoabsorption antenna efficiently extended the absorption range of TiO2 in the visible region, while anatase TiO2 promoted the efficient electron–hole separation of porphyrin. The photo-induced electrons were transferred to the surface of the Pt co-catalyst for the generation of hydrogen via water splitting, and the hole was utilized for the decomposition of methyl orange dye. The hybrid structure showed greatly increased photocatalytic performance compared to the core@shell structure due to massive active sites and increased photo-generated electron output. This controlled assembly regulation provides a new approach for the fabrication of advanced, structure-dependent photocatalysts. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4)-based photocatalysts have garnered significant interest as a promising photocatalyst for hydrogen generation under visible light, to address energy and environmental challenges owing to their favorable electronic structure, affordability, and stability. In spite of that, issues such as high charge carrier recombination rates and low quantum efficiency impede its broader application. To overcome these limitations, structural and morphological modification of the g-C3N4-based photocatalysts is a novel frontline to improve the photocatalytic performance. Therefore, we briefly summarize the current preparation methods of g-C3N4. Importantly, this review highlights recent advancements in crafting high-performance g-C3N4-based photocatalysts, focusing on strategies like elemental doping, nanostructure design, bandgap engineering, and heterostructure construction. Notably, sophisticated doping techniques have propelled hydrogen production rates to a 104-fold increase. Ingenious nanostructure designs have expanded the surface area by a factor of 26, concurrently extending the fluorescence lifetime of charge carriers by 50%. Moreover, the strategic assembly of heterojunctions has not only elevated charge carrier separation efficiency but also preserved formidable redox properties, culminating in a dramatic hundredfold surge in hydrogen generation performance. This work provides a reliable and brief overview of the controlled modification engineering of g-C3N4-based photocatalyst systems, paving the way for more efficient hydrogen production. [ABSTRACT FROM AUTHOR]

A structurally disordered MoSe 2 with rich 1T phase is reported as multi-functional cocatalyst for photocatalytic hydrogen evolution. [Display omitted] • MoSe 2 with different crystallinity degree can be synthesized by controlling reaction kinetics. • Structurally disordered MoSe 2 shows higher efficiency than the crystalline counterparts. • Deep origin of crystallinity-dependent activity is uncovered supported by systematic analysis. The improvement of surface reactivity in noble-metal-free cocatalysts is crucial for the development of efficient and cost-effective photocatalytic systems. However, the influence of crystallinity on catalytic efficacy has received limited attention. Herein, we report the utilization of structurally disordered MoSe 2 with abundant 1T phase as a versatile cocatalyst for photocatalytic hydrogen evolution. Using MoSe 2 /carbon nitride (CN) hybrids as a case study, it is demonstrated that amorphous MoSe 2 significantly enhances the hydrogen evolution rate of CN, achieving up to 11.37 μmol h−1, surpassing both low crystallinity (8.24 μmol h−1) and high crystallinity MoSe 2 (3.86 μmol h−1). Experimental analysis indicates that the disordered structure of amorphous MoSe 2 , characterized by coordination-unsaturated surface sites and a rich 1T phase with abundant active sites at the basal plane, predominantly facilitates the conversion of surface-bound protons to hydrogen. Conversely, the heightened charge transfer capacity of the highly crystalline counterpart plays a minor role in enhancing practical catalytic performance. This approach is applicable for enhancing the photocatalytic hydrogen evolution performance of various semiconducting photocatalysts, including CdS, TiO 2 , and ZnIn 2 S 4 , thereby offering novel insights into the advancement of high-performance non-precious catalysts through phase engineering. [ABSTRACT FROM AUTHOR]

Activity and stability are two scientific issues of concern in catalyst design and synthesis. In this study, supported (CoS/CdS) and encapsulated (CdS@CoS) catalysts were synthesized with controlled variations in solvent. Remarkably, the CoS/CdS exhibited higher activity, achieving an impressive average H 2 generation rate of 29.26 mmol g−1 h−1 for the optimized sample. Conversely, the CdS@CoS demonstrated superior stability, showing no significant activity decline over a 20-h period. These findings highlight the importance of the cocatalyst deposition state in affecting the photocatalytic performance of catalysts. This research provides valuable insights for the synthesis of photocatalysts. [Display omitted] • The controllable synthesis of CoS/CdS and CdS@CoS heterostructures was achieved. • The CoS/CdS demonstrated high activity, whereas the CdS@CoS exhibited long-term stability. • The impact of the deposition state of CoS on catalytic performance was examined. • The photocatalytic mechanism was detailedly analyzed. [ABSTRACT FROM AUTHOR]

This work investigates the potential of ZrO 2 /MoO 3 nanocomposites as catalysts for hydrogen production through NaBH 4 methanolysis. The samples were prepared by controlled thermal calcination and characterized using various techniques like XRD, FTIR, Raman, SEM, and surface area BET analysis. Rietveld refinements verified the presence of the ZrO 2 monoclinic phase with the space group P 2 1 / c in all samples and a second orthorhombic MoO 3 phase with the space group Pnma. The average crystal size decreased from 44 to 40 nm. FTIR and Raman spectroscopy confirmed the successful preparation of ZrO 2 /MoO 3 nanocomposites. SEM analysis showed ZrO 2 particles and MoO 3 nanoparticles adhered to the ZrO 2 surface, potentially creating a rougher texture. The results confirmed the formation of ZrO 2 /MoO 3 nanocomposites with increasing MoO 3 content, leading to an increased surface area of 19–23 m2/g. The catalytic performance evaluation revealed that the sample containing 30 % MoO 3 (ZM3) exhibited the highest hydrogen generation rate of 18,451 mL/g. min at 30 °C. The calculated activation energy for ZM3 was 18.78 kJ/mol, suggesting efficient hydrogen generation at moderate temperatures. [ABSTRACT FROM AUTHOR]