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The development of water electrolysis catalysts that accelerate the oxygen evolution reaction (OER) is a crucial challenge. Ni-based oxides are promising OER catalysts; however, quantitative studies of Ni-based oxides remain unexplored. In this study, we quantitatively evaluated the OER activity of LiNi0.5Mn1.5O4 as a thin-film electrode catalyst. The LiNi0.5Mn1.5O4 thin film fabricated using a sputtering method exhibited a current density of 6.6 and ∼2.6 mAcm−2 for geometric and estimated areas, respectively, at 1.78 V vs. a reversible hydrogen electrode. X-ray photoelectron spectroscopy indicated the presence of Ni3+ in the as-grown and post-OER LiNi0.5Mn1.5O4 thin films. These results suggest that Ni3+ plays a key role in the OER of LiNi0.5Mn1.5O4. [ABSTRACT FROM AUTHOR]

The imperative shift towards decarbonization necessitates the production of clean hydrogen through water electrolysis, powered by renewable energy sources. Among electrolyzer technologies, proton-exchange-membrane (PEM) systems emerge as a promising option for large-scale hydrogen generation due to their modular design and rapid response, aligning well with the intermittency of renewable energy. In this study, we employ a tape casting method to fabricate microporous layers (MPLs), both as a single layer and as a bilayer over commercial porous transport layers (PTLs), to further enhance performance of water electrolyzers. We demonstrate that microporous layers require adequate pore sizes to facilitate gas removal, preventing gas flooding and preserving electrolyzer performance. Our single layer microporous layers exhibit lower overpotentials compared to commercial sintered Ti PTLs by 142 mV at 4 A·cm⁻2. Moreover, we show that having an effective microporous layer enhances electrolyzer performance irrespective of the substrate used, offering avenues for cost reduction. We also investigate novel PTL structures with reduced tortuosity and integrated MPL fabricated via phase inversion tape casting, resulting in a performance enhancement of 92 mV. Our findings unravel the critical role of microporous layer structures and their impact on electrolyzer performance.

Green hydrogen, produced via water electrolysis using renewable electricity, will play a crucial role in decarbonizing industrial and heavy-duty transportation sectors. Anion exchange membrane water electrolyzers (AEMWEs) can overcome many of the performance and cost limitations of incumbent technologies, however, still suffer from durability challenges due to oxidative instability of anion-exchange ionomers. Herein, the use of an electro-active porous transport layer as anode (PTL-electrode) is demonstrated to enable efficient and durable AEMWEs. The stainless-steel PTL-electrodes are shown to have superior performance and durability compared to traditional catalyst layers containing ionomer and nanoparticle catalysts. An AEMWE cell operating at 2 A cm−2 for over 600 h exhibited a degradation rate of just 5 µV h−1. During operation, the surface composition of the stainless steel transforms into a mixture of iron and nickel oxyhydroxides, contributing to enhanced oxygen-evolution reaction activity. The combination of experimental work and modeling elucidates how the bulk structure of the PTL-electrode offers an additional design dimension to further improve electrolyzer performance. Lastly, a surface modification strategy is applied to a PTL-electrode to achieve an even higher performing AEMWE (2.3 vs 2.0 A cm−2 at 1.8 V). Overall, this work lays out pathways toward more efficient, durable, and affordable AEMWEs.

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]

Developing bifunctional catalysts for overall water splitting with high activity and durability at high current density remains a challenge. In an attempt to overcome this bottleneck, in this work, unique CoNiFe-layered double hydroxide nanoflowers are in situ grown on nickel-iron (NiFe) foam through a corrosive approach and following a chemical vapor deposition process to generate nitrogen-doped carbon nanotubes at the presence of melamine (CoNiFe@NCNTs). The coupling effects between various metal species act a key role in accelerating the reaction kinetics. Moreover, the in situ formed NCNTs also favor promoting electrocatalytic activity and stability. For oxygen evolution reaction it requires low overpotentials of 330 and 341 mV in 1M KOH and 1M KOH + seawater to drive 500 mA cm−2. Moreover, water electrolysis can be operated with CoNiFe@NCNTs as both anode and cathode with small voltages of 1.95 and 1.93 V to achieve 500 mA cm−2 in 1M KOH and 1M KOH + seawater, respectively. [ABSTRACT FROM AUTHOR]

Designing low cost, highly active and efficient non-noble metal bifunctional electrocatalysts with remarkable operational reliability for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is indispensable for large-scale water electrolysis and the development of clean energy conversion technologies. Herein, we decorated a two-dimensional (2D) selenium-blended zirconium dioxide (Se-ZrO2) on the surface of a nitrogen-doped carbon heterostructure (Se-ZrO2@NC), which was derived from Zr–metal–organic frameworks (Zr-MOFs), and loaded it on a stainless-steel mesh electrode. Accordingly, phenomenal electrocatalytic performance was observed for the Se-ZrO2@NC-loaded electrode with a minimum overpotential of 48 mV for the HER and 251 mV for the OER at 10 mA cm−2 current density in acidic and alkaline mediums, respectively. Moreover, a complete cell set up was constructed, where the OER and HER were studied at the anode and cathode, respectively, with a cell potential of 1.58 V to reach a current density of 10 mA cm−2 together with an exciting long-term stability of over 48 h. The developed Se-blended 2D transition metal dioxides on the 2D nitrogen-doped carbon heterostructure extended to a variety of catalytically active materials that would provide highly active and stable electrocatalysts for alkaline water splitting studies. [ABSTRACT FROM AUTHOR]

Classic in situ electro‐organic synthesis with substrates in an electrolyzer must compromise process conditions to balance electro‐ and thermochemical steps at both electrodes. This often restricts efficiency and product selectivity, since requirements may deviate for electrochemical (catalyst activation) and chemical (organic synthesis) steps, as well as for paired anode‐ and cathode reactions. Breaking this barrier, we report ex situ electro‐organic synthesis as a versatile method that enables unique product selectivity and unusual product pairs. We exemplify the concept for pairing H2 evolution (HER) with anodic alcohol oxidation. The two‐step method accomplishes this by separating cathode reactions from organic substrate oxidation, and anodic electrocatalyst activation from chemical conversion of organic substrates in time and space. First, the electro‐oxidation of Ni(OH)2 anodes to NiOOH is paired with H2 production by alkaline water electrolysis. Then, "charged" NiOOH electrodes are removed from the electrolyzer and used in external vessels to oxidize model substrate benzyl alcohol under regeneration of Ni(OH)2. Free choice of reaction media outside the electrolyzer allows to selectively obtain benzoic acid (in water) or benzaldehyde (in n‐hexane), whereas classic in situ electrosynthesis only produces the acid together with H2. Perspectively, the method enables electrosynthesis of previously inaccessible products paired to H2 generation. [ABSTRACT FROM AUTHOR]

In acidic proton exchange membrane water electrolysis (PEMWE), the anode oxygen evolution reaction (OER) catalysts rely heavily on the expensive and scarce iridium‐based materials. Ruthenium dioxide (RuO2) with lower price and higher OER activity, has been explored for the similar task, but has been restricted by the poor stability. Herein, we developed an anion modification strategy to improve the OER performance of RuO2 in acidic media. The designed multicomponent catalyst based on sulfate anchored on RuO2/MoO3 displays a low overpotential of 190 mV at 10 mA cm−2 and stably operates for 500 hours with a very low degradation rate of 20 μV h−1 in acidic electrolyte. When assembled in a PEMWE cell, this catalyst as an anode shows an excellent stability at 500 mA cm−2 for 150 h. Experimental and theoretical results revealed that MoO3 could stabilize sulfate anion on RuO2 surface to suppress its leaching during OER. Such MoO3‐anchored sulfate not only reduces the formation energy of *OOH intermediate on RuO2, but also impedes both the surface Ru and lattice oxygen loss, thereby achieving the high OER activity and exceptional durability. [ABSTRACT FROM AUTHOR]

The rationalization of pH‐robust catalysis is highly desired but challengeable for overall water electrolysis (WE). It requests a metal active site that can make an efficient adaption with both cathodic hydrogen and anodic oxygen evolution reactions (HER/OER). Herein, a RuO2‐x/RuSe2 heterostructure electrocatalyst is profiled with interfacial Se─Ru─O bridge for the pH‐robust water splitting studies. An asymmetric bond delta‐polarization (Δp) is found at the interfacial Se─Ru─O bridge, including the Δp > 0 at the Ru─O part and Δp < 0 at the Ru─Se side by both experiment and calculation results. The enlarged Ru─O bond polarizability (Δp > 0) can in principle trigger the lattice oxygen mediated (LOM) pathway for OER; meanwhile, the reduced Ru─Se bond polarizability can benefit the HER due to the strengthened d‐p band hybridization. Resultantly, the heterostructure can deliver ultralow overpotentials of 25/10 mV for Pt‐beyond HER and 210/255 mV for OER at 10 mA cm−2 in acidic/alkaline media, respectively. In especial, the acidic overall WE can be stably operated for 200 h with a low cell voltage of 1.478 V at 10 mA cm−2. This research clarifies the asymmetric bond polarization as the criterion for the rational design of efficient WE catalysts. [ABSTRACT FROM AUTHOR]

The long‐term stability of Ni‐based catalysts, employed in the anode of anion exchange membrane water electrolyzers (AEMWE), has been a persisting concern. In this work, through a simple and powerful electrochemical anodization process, vertically aligned β‐NiOOH atomic sheets (vertical‐β‐NiOOH) grown on Fe‐doped Ni nanoplates (FeNi nanoplates) as a solution are offered. This innovative electrocatalyst demonstrates sustained stability of constant current density for over 120 d during the oxygen evolution reaction.The zero‐gap AEMWE cell harnessing the anodized FeNi nanoplates achieves a remarkable current density of 2.26 A cm−2 at 1.80 V with an energetic efficiency of 85.1%. It is anticipated that the electrochemically produced highly active, stable Ni‐based nanostructures demonstrate the potential in pushing the boundaries of AEMWE technology. [ABSTRACT FROM AUTHOR]

Hydrogen energy with a high fuel value is considered to be one of the most important renewable and clean energy sources in sustainable energy. Electrocatalytic water splitting is the best way to produce hydrogen sustainably on a large scale. In this work, the sand rose‐like MoSe2/NiSe/NiFe layered double hydroxide (NiFe‐LDH) catalyst is obtained by a two‐step hydrothermal method for hydrogen evolution (HER) and oxygen evolution reaction (OER). The three‐dimensional (3D) hierarchical structure is observed by SEM, TEM, XRD and XPS, and the results showed that there is strong electronic interaction among the components, which promotes electron transfer and improves catalytic activity. In the alkaline environment, the catalyst exhibits excellent HER and OER performance, the current density of 10 mA cm−2 requires only 130 mV and 136 mV overpotential, respectively. In the water splitting system composed of MoSe2/NiSe/NiFe‐LDH as both cathode and anode, only 1.51 V voltage reaches the current density of 10 mA cm−2, and workes continuously for more than 120 h at 100 mA cm−2 current density with excellent stability. The Faraday efficiency of hydrogen production is close to 100 %. This study provides a promising strategy for the preparation of efficient electrocatalyst for overall water splitting. [ABSTRACT FROM AUTHOR]

The growing demand for sustainable and healthy practices has led to an increased interest in the electrolyzed water (EW) application. This technology has garnered widespread acceptance as a sanitizer within the food industry. It also enhances the nutritional, functional, and sensory properties of food products to improve quality and safety. This review undertakes a comprehensive review of the recent advancements in electrolysis technology, exploring its applications in fruits and meat industry and its impact on nutritional, functional, microbiological, safety, and sensory characteristics. It is concluded that the EW should be considered an essential component of industrial equipment sanitization and food product decontamination by offering antimicrobial benefits and promoting functional component accumulation. Nevertheless, the effectiveness of EW can be compromised by the presence of organic matter and equipment corrosion. Furthermore, it provides a concise overview of EW generation, elucidates the influential factors governing its production, and delineates prospective directions for research and development in this field. [ABSTRACT FROM AUTHOR]

The utilization of hydrazine in aiding water electrolysis presents a promising avenue for achieving highly efficient hydrogen production through energy conversion. Herein, bifunctional electrocatalyst of urchin‐like iron, nickle‐codoped cobalt phosphide supported on Ni foam (FeNi‐CoP/NF) is reported. Benefitting from the combined electronic structure and lattice strain engineering by Fe and Ni‐ codoping, the hydrazine‐assisted seawater electrolysis assembled with FeNi‐CoP/NF as both electrodes can achieve an industrial‐level current density of 1.5 A cm−2 at a record‐setting voltage of 163 mV at 70 °C and sustain stable operation for hundreds of hours in seawater environment. The existence of a potential coincidence region lends credibility to the feasibility of implementing self‐activated hydrazine‐assisted seawater electrolysis. Based on theoretical calculations, the separate and synergistic effects of electronic structure and lattice strain engineering are investigated and an integrated illustration of these two strategies on enhancing hydrogen evolution and hydrazine oxidation activity is provided. Moreover, an innovative multi‐powered hydrogen generation system featuring a direct hydrazine fuel cell, rechargeable Zn‐hydrazine battery, and hydrazine‐assisted seawater electrolysis is proposed, underscoring the unique advantages of hydrazine oxidation reaction and its prospective contribution to electrochemical energy conversion technologies powered by sustainable sources. [ABSTRACT FROM AUTHOR]

The electrochemical chlorine evolution reaction (CER) is an important electrochemical reaction for industrial applications, but it has serious problems, such as the short service life and low electrolytic efficiency in the extremely dilute chlorine-containing solution. In this paper, a RuO2–TiO2/IrO2–Ta2O5 (RuTi/IrTa) electrode was prepared via a thermal decomposition method involving alternate coating with precursor solutions with two active components, which significantly improved the service lifetime and CER selectivity of electrode materials with low Ir content. The experimental results indicate that the accelerated lifetime (AL) of the RuTi/HC–IrTa electrode with an Ir loading of 374 μg cm−2 can reach 602 h. Although the Ir loading of the HC–IrTa electrode (680 μg cm−2) is about twice that of the RuTi/HC–IrTa electrode, the AL of the HC–IrTa electrode is only 245 h, and the AL of the RuTi electrode (Ru loading: 180 μg cm−2) is only 5 h. If the precursor solutions of HC–IrTa and RuTi electrodes are simply mixed, the AL of the obtained RuTi–HC–IrTa electrode is only 41 h. This suggests that the increase in AL does in fact originate from changing the coating method, rather than simply the use of multiple active components. In addition, the SEM results indicate that the increase of the AL of RuTi/HC–IrTa is due to the change of the corrosion mechanism from pitting corrosion to surface corrosion of active components. Moreover, the CER selectivity of the RuTi/IrTa electrode has also been improved. This may be due to the change in the electronic structure, which is demonstrated through XPS characterization. The RuTi/IrTa electrode has a high electrolysis efficiency in the electrolysis of low-chlorine-concentration solutions. In the preparation of electrochemical disinfection technologies (EDTs), such as acidic electrolyzed water (AEW), more available chlorine content (ACC) can be obtained. [ABSTRACT FROM AUTHOR]

Binder plays a crucial role in constructing high‐performance electrodes for water electrolysis. While most research has been focused on advancing electrocatalysts, the application of binders in electrode design has yet to be fully explored. Herein, the in situ incorporation of polytetrafluoroethylene (PTFE) as a multifunctional binder, which increases electrochemical active sites, enhances mass transfer, and strengthens the mechanical and chemical robustness of oxygen evolution reaction (OER) electrodes, is reported. The NiFe‐LDH@PTFE/NF electrode prepared by co‐deposition of PTFE with NiFe‐layered double hydroxide onto nickel foam demonstrates exceptional long‐term stability with a minimal potential decay rate of 0.034 mV h−1 at 500 mA cm−2 for 1000 h. The alkaline water electrolyzer utilizing NiFe‐LDH@PTFE/NF requires only 1.584 V at 500 mA cm−2 and sustains high energy efficiency over 1000 h under industrial operating conditions. This work opens a new path for stabilizing active sites to obtain durable electrodes for OER as well as other electrocatalytic systems. [ABSTRACT FROM AUTHOR]

In recent years, a variety of methods have been reported to produce hydrogen by electrolysis of water. However, the design of low-cost electrocatalysts is still a great challenge because of the slow dissociation kinetics of water molecules and the poor long-term stability of catalysts in the HER/OER process. In this paper, sulfur-doped molybdenum and cobalt composites (NF@MoSCo) were prepared on the surface of nickel foam (NF) using a facile hydrothermal reaction. After further low-temperature phosphating treatment, nanoflower-like structure composites (NF@MoSCo/Co2P) can be prepared with excellent electrocatalytic properties both for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The as-synthesized composites show an overpotential of 176.3 mV at 100 mA cm−2 for the OER and 180.3 mV at 100 mA cm−2 for the HER. Thus, a symmetric device consisting of Mo and Co-based phosphide nanoflower electrodes was constructed for overall seawater splitting, which can provide a potential of 1.62 V at 100 mA cm−2 in alkaline simulated seawater (1 M KOH + 0.5 M NaCl). This provides a new idea for producing low-resistance and high-efficiency catalysts. [ABSTRACT FROM AUTHOR]

The production of hydrogen (H2) and multi-carbon fuels through water electrolysis (oxygen evolution reaction (OER)/hydrogen evolution reaction (HER)) and water–CO2 co-electrolysis (OER/CO2 reduction reaction (CO2RR)), respectively, is supposed to be the emergent energy carrier. These electrochemical processes are essential chemical conversion pathways that initiate the changes toward production of renewable energy. This review summarizes the systematic design of earth-abundant transition metal-based nanomaterials and their electrocatalytic activities toward electrochemical energy conversion reactions such as OER, HER, and CO2RR. The primary focus is on fabricating highly effective, low-cost, and advanced transition metal-based nanostructures for both the OER/HER and OER/CO2RR systems. Developing synthetic strategies for surface morphology-controlled nanostructured electrocatalysts, engineering the electrode surface, enhancing the electrocatalytic activity, understanding the relationship between intrinsic catalytic activity and preparation approaches or precursor choices, and exploring the reaction mechanism are focused on. Furthermore, the current challenges, figure-of-merit, and prospects of transition metal-based nanomaterials and their electrocatalytic activities toward water electrolysis and water–CO2 co-electrolysis are described. This study may open new opportunities to develop shape-controlled and high-performance electrocatalysts for electrochemical energy conversion and storage reactions. [ABSTRACT FROM AUTHOR]

Hydrogen energy, derived from the electrolysis of water using renewable energy sources such as solar, wind, and hydroelectric power, is considered a promising form of energy to address the energy crisis. However, the anodic oxygen evolution reaction (OER) poses limitations due to sluggish kinetics. Apart from high catalytic activity, the long-term stability of electrocatalytic OER has garnered significant attention. To date, several research studies have been conducted to explore stable electrocatalysts for the OER. A comprehensive review is urgently warranted to provide a concise overview of the recent advancements in the electrocatalytic OER stability, encompassing both electrocatalyst and device developments. This review aims to succinctly summarize the primary factors influencing OER stability, including morphological/phase change and electrocatalyst dissolution, as well as mechanical detachment, alongside chemical, mechanical, and operational degradation observed in devices. Furthermore, an overview of contemporary approaches to enhance stability is provided, encompassing electrocatalyst design (structural regulation, protective layer coating, and stable substrate anchoring) and device optimization (bipolar plates, gas diffusion layers, and membranes). Hopefully, more attention will be paid to ensuring the stable operation of electrocatalytic OER and the future large-scale water electrolysis applications. This review presents design principles aimed at addressing challenges related to the stability of electrocatalytic OER. [ABSTRACT FROM AUTHOR]

Anion exchange membrane (AEM) water electrolysis has emerged as a promising technology for producing hydrogen in a carbon‐neutral economy. To advance its industrial application, performance evaluations of non‐precious metal AEM electrolyzers with electrode areas of 25 cm2 were conducted. The focus was on pure water operation, achieving a current density of 0.26 A cm−2 at a voltage of 2.2 V. To gain a better understanding, the AEM electrolyzer was also operated in aqueous KOH, yielding 1.2 A cm−2 at 2.2 V. By adding a liquid electrolyte and by varying cell components, causes of the occurring performance limitations and ways to improve the AEM electrolyzer were identified. Electrochemical impedance analysis showed that the activation loss at the anode due to sluggish OER kinetics was the limiting factor at low current densities. At higher current densities, which is the operating range of interest for industrial application, the ohmic resistance from the membrane was the dominant factor limiting high performance in pure water operation. [ABSTRACT FROM AUTHOR]

Electrochemical pH-swing strategies offer a promising avenue for cost-effective and energy-efficient carbon dioxide (CO2) capture, surpassing the traditional thermally activated processes and humidity-sensitive techniques. The concept of elevating seawater's alkalinity for scalable CO2 capture without introducing additional chemical as reactant is particularly intriguing due to its minimal environmental impact. However, current commercial plants like chlor-alkali process or water electrolysis demand high thermodynamic voltages of 2.2 V and 1.23 V, respectively, for the production of sodium hydroxide (NaOH) from seawater. These high voltages are attributed to the asymmetric electrochemical reactions, where two completely different reactions take place at the anode and cathode. Here, we developed a symmetric electrochemical system for seawater alkalization based on a highly reversible and identical reaction taking place at the anode and cathode. We utilize hydrogen evolution reaction at the cathode, where the generated hydrogen is looped to the anode for hydrogen oxidation reaction. Theoretical calculations indicate an impressively low energy requirement ranging from 0.07 to 0.53 kWh/kg NaOH for established pH differences of 1.7 to 13.4. Experimentally, we achieved the alkalization with an energy consumption of 0.63 kWh/kg NaOH, which is only 38% of the theoretical energy requirements of the chlor-alkali process (1.64 kWh/kg NaOH). Further tests demonstrated the system's potential of enduring high current densities (~20 mA/cm²) and operating stability over an extended period (>110 h), showing its potential for future applications. Notably, the CO2 adsorption tests performed with alkalized seawater exhibited remarkably improved CO2 capture dictated by the production of hydroxide compared to the pristine seawater. [ABSTRACT FROM AUTHOR]

Due to the high cost of ultra‐pure water supply and the mismatch between water sources and renewable energy distribution, the large‐scale production of green hydrogen through seawater electrolysis has generated significant interest. This presents an attractive potential technology within the framework of carbon‐neutral energy production. However, owing to the complex composition of seawater, particularly the competitive oxidation reactions and corrosion issues involving Cl−, seawater electrolysis has suffered from low selectivity and poor stability in oxygen evolution reaction (OER), which severely impact the efficiency of hydrogen production and hinder the practical applications. To further promote in‐depth research and practical applications of seawater electrolysis, this review introduces the principles, key advantages, and challenges of seawater electrolysis. Specifically, the design strategies are categorized for highly active OER electrocatalysts for seawater electrolysis, including catalyst design, design of chemical reaction systems, and other special process design. To ensure long‐term operational stability of seawater electrolysis, various strategies such as employing self‐supporting materials, surface protection strategies, and electrolyzer design, are discussed. Finally, current challenges and future prospects for the industrialization of seawater electrolysis are proposed and discussed. It is expected that this review provides new insights for large‐scale seawater‐based hydrogen production in the future. [ABSTRACT FROM AUTHOR]

Existing cleaning methods mainly focus on removing free‐state pesticides. However, mancozeb can bind to the wax layer of grapes, forming bound‐state residues that are difficult to remove. This study aims to develop an effective cleaning strategy to eliminate both free and bound mancozeb residues from grapes. Compared with the untreated mancozeb aqueous solution, the concentration of free mancozeb significantly decreased (p < 0.05) after treatment with ozonated water (OW), electrolyzed water (EW), and their combination (OW+EW) for 60 min. The combined treatment synergistically promoted mancozeb degradation, thus reducing its half‐life to 38% and 75% of that observed when OW and EW were used alone, respectively. To investigate the effect of the waxy layer on mancozeb removal, oleanolic acid (OLA) was selected as a representative component. The binding effect of OLA limited the degradation of mancozeb in OW and EW, extending its half‐life by 1.27 and 1.20 times, respectively. Density functional theory elucidated the mechanism by which the binding of OLA affects the degradation of mancozeb. Interestingly, the decomposition of mancozeb in OW + EW was almost unaffected by the introduction of OLA, indicating that the combined treatment could effectively remove bound‐state mancozeb. The combined treatment was then successfully applied to remove mancozeb from grapes. After exposure to OW + EW for 10 min, the removal efficiency of mancozeb reached up to 80.61% with minimal risks of ethylene thiourea formation. There was no obvious change in the surface color of grapes after treatment. The findings provide valuable guidance for removing mancozeb from fresh fruits rich in waxy coatings. [ABSTRACT FROM AUTHOR]

Developing transition metal based overall water splitting (OWS) electrocatalysts with high efficiency, low‐cost, large current density, and long‐term stability is crucial for industrial electrolysis of water, but remains a major challenge. In this study, a hierarchical electrocatalyst with MoS2/Ni3S2 heterojunctions and a tiny amount of Au nanoparticles grown on nickel foam (MoS2/Ni3S2‐Au@NF) has been developed by a one‐step hydrothermal method. The heterojunctions and Au nanoparticle decoration induce the electron‐rich interfaces in the catalyst, which facilitate the synergistic adsorption of both OER and HER intermediates. As a result, MoS2/Ni3S2‐Au@NF possesses an excellent bifunctional electrocatalytic performance in 1 M KOH with low HER overpotential (78 mV@10 mA cm−2, 253 mV@500 mA cm−2), low OER overpotential (261 mV@50 mA cm−2, 435 mV@500 mA cm−2), and outstanding cyclical stability and continuous stability, which are superior than typical benchmarks of Pt/C and RuO2. An electrolyzer assembled with the self‐supported MoS2/Ni3S2‐Au@NF electrode also displays excellent OWS activity and stability with a current density beyond 100 mA cm−2. This experiment is responding a potential alternative non‐precious metal electrocatalyst for OWS at industrial settings, and thus promotes the real‐world application of hydrogen energy conversions. [ABSTRACT FROM AUTHOR]

The deprived electrochemical kinetics of the oxygen evolution reaction (OER) catalyst is the prime bottleneck and remains the major obstacle in the water electrolysis processes. Herein, a facile hydrothermal technique was implemented to form a freestanding polyhedron-like Co3O4 on the microporous architecture of Ni foam, its reaction kinetics enhanced through sulfide counterpart transformation in the presence of Na2S, and their catalytic OER performances comparatively investigated in 1 M KOH medium. The formed Co3S4 catalyst shows outstanding catalytic OER activity at a current density of 100 mA cm−2 by achieving a relatively low overpotential of 292 mV compared to the pure Co3O4 catalyst and the commercial IrO2 catalyst. This enhancement results from the improved active centers and conductivity, which boost the intrinsic reaction kinetics. Further, the optimized Co3S4 catalyst exhibits admirable prolonged durability up to 72 h at varied current rates with insignificant selectivity decay. The energy dispersive X-ray spectroscopy (EDX) and Raman spectra measured after the prolonged OER stability test reveal a partial transformation of the active catalyst into an oxyhydroxide phase (i.e., CoOOH@Co3S4), which acts as an active catalyst phase during the electrolysis process. [ABSTRACT FROM AUTHOR]

The integration of wind and solar energy with green hydrogen technologies represents an innovative approach toward achieving sustainable energy solutions. This review examines state-of-the-art strategies for synthesizing renewable energy sources, aimed at improving the efficiency of hydrogen (H2) generation, storage, and utilization. The complementary characteristics of solar and wind energy, where solar power typically peaks during daylight hours while wind energy becomes more accessible at night or during overcast conditions, facilitate more reliable and stable hydrogen production. Quantitatively, hybrid systems can realize a reduction in the levelized cost of hydrogen (LCOH) ranging from EUR 3.5 to EUR 8.9 per kilogram, thereby maximizing the use of renewable resources but also minimizing the overall H2 production and infrastructure costs. Furthermore, advancements such as enhanced electrolysis technologies, with overall efficiencies rising from 6% in 2008 to over 20% in the near future, illustrate significant progress in this domain. The review also addresses operational challenges, including intermittency and scalability, and introduces system topologies that enhance both efficiency and performance. However, it is essential to consider these challenges carefully, because they can significantly impact the overall effectiveness of hydrogen production systems. By providing a comprehensive assessment of these hybrid systems (which are gaining traction), this study highlights their potential to address the increasing global energy demands. However, it also aims to support the transition toward a carbon-neutral future. This potential is significant, because it aligns with both environmental goals and energy requirements. Although challenges remain, the promise of these systems is evident. [ABSTRACT FROM AUTHOR]

This study develops a semi-empirical model of an alkaline water electrolyzer (AWE) based on thermodynamic and electrochemical principles to investigate cell voltage behavior during electrolysis. By importing polarization curve test data under specific operational conditions, eight undefined parameters are precisely fitted, demonstrating the model's high accuracy in describing the voltage characteristics of alkaline electrolyzers. Additionally, an AWE system model is introduced to examine the influence of various operational parameters on system efficiency. This innovative approach not only provides detailed insights into the operational dynamics of AWE systems but also offers a valuable tool for optimizing performance and enhancing efficiency, advancing the understanding and optimization of AWE technologies. [ABSTRACT FROM AUTHOR]

This review highlights the critical effects of heat transfer and bubble mass transfer in alkaline water electrolysis on hydrogen generation efficiency. To improve heat transfer performance, the study focuses on reducing electrical resistance and controlling the electrolysis system's temperature. It proposes innovative strategies such as using metal matrix composites and catalysts to optimize electrode structure, precise temperature and pressure regulation and enhanced electrolyte concentration. Additionally, the study examines the dynamics of bubble mass transfer, proposing effective strategies to reduce bubble coverage, including hydrophilic electrodes, mechanically circulating the electrolyte and voltage smoothing with pressure swinging. This study contributes to the advancement of hydrogen energy technology with practical strategies. By adjusting the electrolysis system to optimize the combined effect of these factors, we can improve the efficiency, economy and environmental friendliness of hydrogen production. This will contribute to the transformation of the global energy mix and the implementation of sustainable development strategies. [ABSTRACT FROM AUTHOR]

Traditional iridium (Ir) oxide catalysts have faced significant limitations in water electrolysis, particularly under acidic conditions where instability and degradation severely restrict the efficiency of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). To overcome these challenges, this study successfully synthesized highly dispersed IrPtPdNi alloy nanoparticles on a graphene oxide support using a vertically moving reactor, demonstrating exceptional performance in water electrolysis. These nanoparticles, synthesized via a fast-moving bed pyrolysis method, combine iridium, platinum, palladium, and nickel. They exhibit lower overpotentials in OER and comparable performance in HER to commercial catalysts, while also offering enhanced stability. These results surpass the limitations of traditional catalysts, marking significant progress toward more efficient and sustainable hydrogen production technologies. This advancement is expected to contribute significantly to the development of sustainable energy systems by innovatively enhancing the performance of catalysts in the electrochemical water-splitting process. [ABSTRACT FROM AUTHOR]

Powered by clean energy, the hydrogen fuel production from seawater electrolysis is a sustainable green hydrogen technology, however, chlorine corrosion and correlative oxidation reactions severely erode the catalysts. Our previous work demonstrates that direct seawater electrolysis without a desalination process and strong alkali addition can be realized by introducing a hard Lewis acid oxide on the catalyst surface to capture OH−. However, the criteria for selecting Lewis acid oxides and the origin of OH− enrichment in chlorine chemistry inhibition on the catalyst surface remain unexplored. Here, we compare the ability of a series of Lewis acid oxides with different acidity constants (pKa), including MnO2, Fe2O3, and Cr2O3, to enrich OH− on the Co3O4 anode catalyst surface. Comprehensive analyses suggest that the lower pKa value of the Lewis acid oxide, the higher concentration of OH− enriched on Co3O4 surface, and the lower Cl− concentration. As established correlation among pKa of Lewis acid oxide, OH− enrichment and Cl− repulsion provide direct guidance for future design of highly active, selective and durable catalysts for natural seawater electrolysis. [ABSTRACT FROM AUTHOR]

To ensure the green and sustainable advancement of hydrogen energy, there is a critical need for the development of a cost-effective catalyst to address the sluggish kinetics of water electrolysis under alkaline conditions. An approach to achieve this is by constructing ultrathin Pt shell-structured catalysts that offer enhanced electrocatalytic hydrogen evolution reaction performance through modulation of the inner core while minimizing costs. Herein, an ultrathin Pt shell catalyst with an inner core consisting of a PtNi face-centered cubic and hexagonal-close-packed mixed-phase interface (named PtNi-mix) is synthesized through a pre-synthesis method followed by post-acid etching process. Encouragingly, the PtNi-mix catalyst only requires 12.9 mV overpotential to achieve a current density of 10 mA·cm-2 in 1 M KOH, which is much lower than that of the commercial 20 wt.% Pt/C catalyst (71.2 mV). Also, it possesses a high mass activity (7.2 A·mg-1) at an overpotential of 70 mV, which is 9 times higher than that of the commercial 20 wt.% Pt/C catalyst. Additionally, the performance of the PtNi-mix catalyst remains almost unchanged after 10,000 cyclic voltammetry tests, indicating that the catalyst exhibits excellent stability. [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]

This document is a profile of Jinfa Chang, a new editorial board member of Frontier Reporters for the Chinese Journal of Chemistry. Chang is a professor at Northeast Normal University in China and has a background in chemistry, with a focus on electrocatalytic hydrogen energy-electric energy conversion. Chang's research aims to design and develop cost-effective, high-performance catalysts to accelerate the commercialization of hydrogen-related energy storage and conversion technologies. The lab pays particular attention to the electrocatalytic performance of electrode materials for fuel cells and water electrolysis under real-service conditions, with a specific interest in the reaction mechanism and structure-performance relationship. [Extracted from the article]

This work investigates the use of Ti6Al4V as flow field plates in PEM-based electrolyzer stacks, utilizing its good corrosion resistance and high mechanical strength. The study explores the development of durable conductive coatings on Ti6Al4V surfaces. The coated surfaces are characterized by X-ray diffraction (XRD), showing the characteristic peaks of Pt deposited and the presence of Pt, PtO2, and TiO2 after thermal oxidation. Field emission scanning electron microscopy reveals a uniform Pt coating on Ti6Al4V with a thickness of 2–3 µm. Potentiodynamic studies revealed improved corrosion resistance with a corrosion current density of 2.1 µA·cm⁻2 in Ti6Al4V-PA-AD-TO compared to Ti6Al4V. Stability under 2 V vs. SHE for 5 h in a PEM water electrolyzer anodic environment is demonstrated, along with an evaluation of performance in a PEM electrolyzer single cell. The durability of the developed coating is assessed over 100 h in a single-cell setup, offering insights into cost-effective PEM-based electrolyzer stacks. The reduction of reliance on precious metals and the enhancement of durability provide a promising method for achieving economic viability in the production of hydrogen through water electrolysis. [ABSTRACT FROM AUTHOR]

Self‐repairing catalysts are useful for achieving alkaline water electrolyzers with long lifetimes under intermittent operation. However, rational methodologies for designing self‐repairing catalysts have not yet been established. Herein, hybrid cobalt hydroxide nanosheets (Co‐ns), with a high deposition (repairing) rate, and β‐FeOOH nanorods (Fe‐nr), with high oxygen evolution reaction (OER) ability, are electrostatically self‐assembled into composite catalysts. This strategy is developed to integrate multifunctionality in self‐repairing catalysts. Positively charged Co‐ns and negatively charged Fe‐nr form uniform composites when dispersed in an electrolyte. These composites are electrochemically deposited on a nickel electrode by electrolysis at 800 mA cm−2. Co‐ns form a conductive mesoporous assembly of CoOOH nanosheets as a support. Fe‐nr are then distributed on the CoOOH nanosheets as active sites for the OER. Because of the high deposition rate of Co‐ns, the amount of Fe‐nr deposited increases 22 times compared to when Fe‐nr is deposited alone, and the OER current density increases 14 times compared to that of Co‐ns alone. The composite self‐repair catalyst shows the highest activity and durability under an accelerated durability test (ADT), and its degradation rate decreases from 84 μV cycle−1 (Fe‐nr only) to 60 μV cycle−1 (composite catalyst) under ADT conditions without repair. [ABSTRACT FROM AUTHOR]

So far, the sol-gel process has been available to prepare precursor gels of bioactive glasses with various compositions. In this report, we described a novel coating method of bioactive gels on a titanium substrate where the sol-gel transition is controlled by applying external electric fields. The application of a constant current of 10 mA/cm2 in an acidic sol containing pre-hydrolyzed tetraethoxysilane, calcium nitrate, and ammonium dihydrogen phosphate led to the deposition of gels on the titanium cathodes due to the generation of OH– by water electrolysis as a catalyst of the sol-gel transition. The obtained gels, which were characterized to be amorphous and consisted of Si, Ca, and P, covered the titanium substrates as a coating. The bioactivity of the gels deposited was confirmed by soaking in a simulated body fluid (SBF) up to 7 days, suggesting that the electrochemically assisted sol-gel process is promising for providing bioactive coatings on metallic implants. Highlights: The electrochemically assisted sol-gel processing successfully led to the deposition of bioactive gel coating on titanium substrates. The gels were amorphous and consisted of Si, Ca, and P, characterized by XRD, FT-IR, SEM, and EDX. The gels successfully formed apatite on them in a simulated body fluid (SBF) for at least 1 day. The novel and straightforward electrochemical method in providing bioactivity is promising for surface modification of metallic implants. [ABSTRACT FROM AUTHOR]

Recurring environmental challenges and the global energy crisis have led to intensified research on alternative energy sources. Hydrogen has emerged as a promising solution, produced through electrochemical, thermochemical, and biological methods. This study presents the advantages and disadvantages of these technologies. It also provides pertinent data on hydrogen production, identifying world‐leading countries in hydrogen production, such as the USA, Japan, and China, and the government policies that they have adopted. It reports market trends such as hydrogen synthesis by water electrolysis, the high cost of the electrolyzers used, and incentives for the carbon market to become competitive with other alternative energy sources. It also highlights startups from around the world that are developing innovative methodologies for producing hydrogen. The study concludes that integrating hydrogen production concepts with social, environmental, and industry interests is essential. [ABSTRACT FROM AUTHOR]

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Ti3C2, one typical MXene, has great potential to be coupled with various transition metals. Herein, a novel and effective catalyst is developed by synergistically loading VCoCOx onto Ti3C2‐modified nickel foam (VCoCOx–Ti3C2@NF). Field emission scanning electron microscope and high‐resolution transmission electron microscopy are employed to characterize the morphology and structure. As expected, the catalyst optimized by response surface methodology attains overpotentials of 290 and 64 mV and Tafel slopes of 82 and 79 mV dec−1 for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. By using the bifunctional VCoCOx–Ti3C2@NF catalyst, the water splitting current density achieves 10 mA cm−2 in 1.0 mol L−1 KOH electrolyte at cell voltage of 1.52 V, comparable with the noble metal electrolyzer Pt@C@NF||RuO2@NF (1.57 V). Furthermore, the resulting catalyst exhibits excellent cycling durability after 120 h of continuous catalysis, which retains 103.8% and 105.4% of potential (V vs reversible hydrogen electrode) for OER and HER, respectively. Density functional theory calculation reveals that the Gibbs free energy barriers for the OER and HER intermediates are reduced due to the integration of VCoCOx with Ti3C2@NF. The fabricated VCoCOx–Ti3C2@NF catalyst is a promising electrochemical material for clean energy production. [ABSTRACT FROM AUTHOR]

Solid oxide cells (SOCs) are a promising dual‐mode technology for the production of hydrogen through high‐temperature water electrolysis, and the generation of power through a fuel cell reaction that consumes hydrogen. Switching between these two modes as the price of electricity fluctuates requires reversible SOC operation and accurate tracking of hydrogen and power production set points. Moreover, a well‐functioning control system is important to avoid cell degradation during mode‐switching operation. In this article, we apply nonlinear model predictive control (NMPC) to an SOC module and supporting equipment and compare NMPC performance to classical proportional‐integral (PI) control strategies, while switching between the modes of hydrogen and power production. While both control methods provide similar performance across various metrics during mode switching, NMPC demonstrates a significant advantage in reducing cell thermal gradients and curvatures (mixed spatial‐temporal partial derivatives), thereby helping to mitigate long‐term degradation. [ABSTRACT FROM AUTHOR]

Efficient catalysts are imperative to accelerate the slow oxygen reaction kinetics for the development of emerging electrochemical energy systems ranging from room-temperature alkaline water electrolysis to high-temperature ceramic fuel cells. In this work, we reveal the role of cationic inductive interactions in predetermining the oxygen vacancy concentrations of 235 cobalt-based and 200 iron-based perovskite catalysts at different temperatures, and this trend can be well predicted from machine learning techniques based on the cationic lattice environment, requiring no heavy computational and experimental inputs. Our results further show that the catalytic activity of the perovskites is strongly correlated with their oxygen vacancy concentration and operating temperatures. We then provide a machine learning-guided route for developing oxygen electrocatalysts suitable for operation at different temperatures with time efficiency and good prediction accuracy. Catalyst screening is an important process but it's usually time-consuming and labor intensive. Here the authors report the prediction of oxygen vacancy for perovskites using machine learning techniques to develop suitable oxygen electrocatalysts for solid oxide fuel cells at reduced temperatures. [ABSTRACT FROM AUTHOR]

Hybrid water electrolysis offers a groundbreaking approach to energy‐saving hydrogen production by utilizing thermodynamically favorable and value‐added reactions to replace sluggish anodic oxygen evolution in overall water splitting. However, numerous anodic processes generate intermediates or products incompatible with aqueous environments, thereby degrading anodic performance to limit the efficiency and durability of hybrid water electrolysis. Herein, this difficulty is addressed by applying anodic mass transport intensification in conjunction with catalyst engineering, realizing a long‐lasting hybrid seawater electrolysis coupling sulfion oxidation reaction (SOR) for efficient hydrogen production below 1.2 V at an industrial‐level current density of 500 mA cm−2. An exceptional longevity of 2000 h is achieved for the electrolysis by eliminating anode passivation by sulfur deposition during SOR, a general concern in the sulfur‐involved industrial sector. This technology cut the electricity expense of hydrogen production to 2.80 kWh m−3 H2, undercutting alkaline water electrolysis by 34.9–51.1%. Simultaneously, fast upcycling of sulfion pollutants to value‐added sulfur is achieved to add additional economic and environmental profits, enabling hydrogen production at a midpoint expense ($ 0.93) of the United States Department of Energy's 2026 target ($ 2.0) for the cost per gallon of gasoline‐equivalent. [ABSTRACT FROM AUTHOR]

Understanding the dynamics changes of the water network at the electrode–solution interface during the hydrogen evolution reaction (HER) process, including how it is doubly regulated by the electrode material and electrolyte pH, and its subsequent effects on the reaction intermediates (H* and OH*), is crucial in electrochemistry. However, relevant studies are limited due to water's its dual role as both a reactant and a solvent. Thus, it is essential to construct an ideal model capable of decoupling the effects of interfacial water action from the surface catalytic HER process. In this study, M‐O atom pairs doped MoSe2 model catalyst is developed to achieve this goal and tailor the water network structure in a double‐layer microenvironment. Combined with molecular dynamics simulations and in situ spectroscopic characterization, correlations between water configuration, the water network, and water dissociation with HER activity are successfully established. This findings reveal that the pH‐dependent hydrogen‐bonding environment, modulated by oxophilic species, exerts a greater influence on acidic HER compared to alkaline media. The optimized Rh,O‐MoSe2‐x catalyst demonstrates exceptional performance in both acid and alkaline electrolytes and shows no activity decay during a PEMWE test at 1.5 A cm−2, making it promising for scalable water electrolyzers. [ABSTRACT FROM AUTHOR]

Reducing the cost of PEM water electrolyzers is crucial for making green hydrogen economically viable achievable by cheaper catalysts as well as bipolar plates. This study demonstrates for the first time the use of uncoated carbon bipolar plates (C‐BPs) as an alternative to titanium bipolar plates (Ti‐BPs). The corrosion phenomena of C‐BPs versus Ti‐BPs are investigated through ex situ and in situ accelerated stress tests. The findings show that pH values, especially between 1 and 0, exponentially influence the corrosion current density of bipolar plates. Ex situ tests revealed significantly higher corrosion current densities for C‐BPs compared to Ti‐BPs (e.g., 170 times higher at pH 1 and 80 °C). Yet, tests applying C‐BPs in a Proton Exchange Membrane Electrolyzer operated for at least 567 h at alternating current densities of 1 and 3 A cm⁻2 with low degradation rates (16.41 µV h⁻¹ at 1 A cm⁻2 and 31.92 µV h⁻¹ at 3 A cm⁻2), comparable to Ti‐BPs. Contrary to general perceptions, C‐BPs are stable under application‐ready conditions and do not corrode as previously expected. This study highlights the potential of C‐BPs in electrolyzers, showcasing the potential to reduce the costs of the electrolyzers. [ABSTRACT FROM AUTHOR]

Atomic Fe sites enabled electrochemical carbon dioxide (CO2) reduction (ECO2R) to carbon monoxide (CO) at low overpotentials. However, the narrow potential ranges for selective CO2 conversion on atomic Fe sites hindered the CO production at high current densities. Therefore, unveiling the CO2 electroreduction processes and clarifying the catalytic mechanisms on different atomic Fe sites are important for better design of atomic Fe catalysts toward efficient ECO2R. Herein, the ECO2R processes on single‐atom, dual‐atom, and cluster Fe sites are systematically investigated, and clarify that the balanced water dissociation and CO2 protonation on dual‐atom Fe sites promote the efficient CO production. The dual‐atom Fe catalyst achieves Faradaic efficiencies of CO (FECO) above 92% over a wide potential range of −0.4–−0.9 V versus reversible hydrogen electrode and maintains FECO of 91% after 153‐h electrolysis in H‐type cell. Benefitting from the favorable CO2 protonation for ECO2R on dual‐atom Fe sites, pH‐universal CO2 electroreduction is achieved in alkali‐/acid‐/bicarbonate‐fed membrane electrode assembly electrolyzer, with FECO exceeds 98% in strongly acidic/alkaline and neutral mediums. The work reveals a water dissociation‐promoted CO2 electroreduction on dual‐atom Fe sites and presents a feasible regulation of atomic Fe sites for highly active/selective ECO2R. [ABSTRACT FROM AUTHOR]

Transition metal compounds (TMCs) are potentially fruitful substitutes for noble metals for electrocatalytic splitting of water due to their intrinsic electrocatalytic activity, modifiable morphology, tunable electronic structure and their earth‐abundance. The combination of TMCs with graphene improves the dispersion of loaded catalysts, providing more catalytic active sites, enhancing the conductivity of hybrids, affording accelerated charge‐transfer kinetics, and minimizing catalyst bleaching, aggregation, and sintering under harsh reaction conditions. Additionally, graphene incorporation into TMCs modulates the electronic structure of active centers because of the synergistic interaction between them, thereby improving their catalytic performance. This review paper focuses on the recent progress made in designing different graphene‐transition metal‐based materials that can be used in the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and overall water splitting (OWS). In‐situ characterization methodologies and DFT calculations that facilitate catalyst development are discussed elaborately. Finally, the advancements made in the development of graphene‐supported transition metal compounds for use in a functional water electrolyzer have been explored. In conclusion, a few specific recommendations have been made about the current challenges related to the widespread production of effective HER/OER electrocatalysts for water electrolysis. [ABSTRACT FROM AUTHOR]

Producing hydrogen efficiently through water electrolysis could greatly reduce fossil fuel consumption. As well as this renewable energy source will also help combat global warming and boost economic investment opportunities. This paper studied some factors affecting the performance of oxy-hydrogen/hydroxy (HHO) gas generator, such as applied voltage (from 10.5 to 13.0 V) and electrolyte solution concentration (from 0.05 to 0.20 M), using a dry fuel cell based on the electrolyzing technique of water. The results revealed that the HHO gas production rate, power consumption, and temperature change of electrolyte solution increased significantly with increasing the tested applied voltage and electrolyte concentration. This study concluded that the optimum conditions for producing HHO gas ranged from 11.5 to 12.0 V for applied voltage and from 0.05 to 0.10 M for KOH concentration according to the lowest specific energy and highest HHO gas generator efficiency. Under the previous optimum conditions, the highest productivity, specific energy, and efficiency of the HHO gas generator were 343.9 cm3 min−1, 3.43 kW h m−3, and 53.79%, respectively, using 12.0 V for applied voltage and 0.10 M for electrolyte solution concentration. These findings provide an unambiguous direction for adjusting the operational factors (applied voltage and electrolyte concentration) for efficient HHO gas production and use in different applications. Furthermore, the required energy to operate the HHO gas generator can be obtained from renewable sources. [ABSTRACT FROM AUTHOR]

Designing high‐entropy oxyhydroxides (HEOs) electrocatalysts with controlled nanostructures is vital for efficient and stable water‐splitting electrocatalysts. Herein, a novel HEOs material (FeCoNiWCuOOH@Cu) containing five non‐noble metal elements derived by electrodeposition on a 3D double‐continuous porous Cu support is created. This support, prepared via the liquid metal dealloying method, offers a high specific surface area and rapid mass/charge transfer channels. The resulting high‐entropy FeCoNiWCuOOH nanosheets provide a dense distribution of active sites. The heterostructure between Cu skeletons and FeCoNiWCuOOH nanosheets enhances mass transfer, electronic structure coupling, and overall structural stability, leading to excellent activities in the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and water splitting reaction. At 10 mA cm−2, the overpotentials for OER, HER, and water splitting in 1.0 m KOH solution are 200, 18, and 1.40 V, respectively, outperforming most current electrocatalysts. The catalytic performance remains stable even after operating at 300 mA cm−2 for 100, 100, and over 1000 h, correspondingly. This material has potential applications in integrated hydrogen energy systems. More importantly, density functional theory (DFT) calculations demonstrate the synergy of the five elements in enhancing water‐splitting activity. This work offers valuable insights for designing industrial water electrolysis systems. [ABSTRACT FROM AUTHOR]

The pursuit of carbon‐neutral energy has intensified the interest in green hydrogen production from direct seawater electrolysis, given the scarcity of freshwater resources. While Ni‐based catalysts are known for their robust activity in alkaline water oxidation, their catalytic sites are prone to rapid degradation in the chlorine‐rich environments of seawater, leading to limited operation time. Herein, we report a Ni(OH)2 catalyst interfaced with laser‐ablated LiFePO4 (Ni(OH)2/L‐LFP), derived from spent Li‐ion batteries (LIBs), as an effective and stable electrocatalyst for direct seawater oxidation. Our comprehensive analyses reveal that the PO43− species, formed around L‐LFP, effectively repels Cl− ions during seawater oxidation, mitigating corrosion. Simultaneously, the interface between in situ generated NiOOH and Fe3(PO4)2 enhances OH− adsorption and electron transfer during the oxygen evolution reaction. This synergistic effect leads to a low overpotential of 237 mV to attain a current density of 10 mA cm−2 and remarkable durability, with only a 3.3 % activity loss after 600 h at 100 mA cm−2 in alkaline seawater. Our findings present a viable strategy for repurposing spent LIBs into high‐performance catalysts for sustainable seawater electrolysis, contributing to the advancement of green hydrogen production technologies. [ABSTRACT FROM AUTHOR]

Electrodes with a maximal active site density are critical for high‐performance high‐temperature electrochemical cells (HTECs). One widely employed approach involves the use of porous nanostructures with a high surface‐to‐volume ratio. However, their active site densities inevitably decrease owing to particle aggregation induced at high temperatures, necessitating further development of electrode processing techniques. Taking Pt/yttria‐stabilized zirconia (YSZ) interface as a model system, a Pt nanostructured textile akin to the cantaloupe‐rind pattern with high mechanical integrity is fabricated. Application of an AC voltage to this textile electrode at an elevated temperature reduces the Pt particle size from submicron to 10–80 nm forming a nanocomposite with YSZ, accompanied by a 40‐fold increase in current density under high‐temperature water electrolysis conditions. Furthermore, the AC voltage application to a partially aggregated electrode restores its nano‐blended structure associated with the recovery of its activity. This technique is effective in counteracting particle aggregation on demand, providing an alternative approach to achieve high performance and extended lifetimes in HTECs. [ABSTRACT FROM AUTHOR]

Seawater electrolysis holds great promise for sustainable green hydrogen generation, but its implementation is hindered by high energy consumption and electrode degradation. Two dimensional (2D) layered double hydroxide (LDH) exhibits remarkable stability, high catalytic activity, and excellent corrosion resistance in the harsh electrolytic environment. The synergistic effect between LDH and seawater ions enhances the oxygen evolution reaction, enabling efficient and sustainable green hydrogen generation. Here, we report a synthesis of low cost, novel 2D Vanadium Copper (VCu) LDH first time in the series of LDH's as a highly efficient bifunctional electrocatalyst. The electrochemical (EC) and photoelectrochemical (PEC) study of VCu LDH and VCu LDH/Graphite Carbon Nitride (g‐C3N4) nanohybrid was performed in 0.5 M H2SO4 (acidic), 1 M KOH (basic), 0.5 M NaCl (artificial seawater), 0.5 M NaCl+1 M KOH (artificial alkaline seawater), real seawater and 1 M KOH+real seawater (alkaline real seawater) electrolyte medium. It was found that VCu LDH shows a remarkable lower overpotential of 72 mV hydrogen evolution reaction (HER) and 254 mV oxygen evolution reaction (OER) at current density of 10 mA/cm2 under alkaline real seawater electrolysis exhibiting bifunctional activity and also showing better stability. [ABSTRACT FROM AUTHOR]