ABSTRACT Hydrogen energy has many potential applications in manufacturing, transportation, and other industries. However, demand forecasts for industrial hydrogen are limited and unreliable. Based on the source of production, hydrogen energy can be divided into three categories: “gray hydrogen,” “blue hydrogen,” and “green hydrogen.” Among these, “gray hydrogen” is produced using fossil fuels and has high carbon emissions; “blue hydrogen” combines carbon capture and storage technology and has relatively low carbon emissions; “green hydrogen” is produced using renewable energy electrolysis and has zero carbon emissions. The study in this paper focuses on green hydrogen, which is hydrogen produced by electrolysis of water. This paper investigates the demand for industrial hydrogen using ammonia production as a case study, and it creates an intelligent forecast model for hydrogen demand. This model is built on PSO, which enhances RF, and an Optimized Least Squares Support Vector Machine modified with the Sparrow Algorithm. Firstly, this paper uses text mining to create a library of influencing factor indicators. The essential components are filtered out using a Random Forest improved on the particle swarm technique to prioritize their importance. Secondly, the paper presents an intelligent projection of the demand for industrial hydrogen in ammonia synthesis, with forecast findings ranging from 2024 to 2035. This enables us to calculate the total hydrogen demand in the industrial sector. Finally, an empirical analysis is performed using industrial hydrogen ammonia synthesis data from the national database. The intelligent prediction model proposed in this paper achieves the lowest MAPE of 7.77% and RMSE of 401.06 tons, superior to other comparison models. By 2035, ammonia demand is projected to reach 56.5 million tons, requiring 1527.23 tons of industrial hydrogen. The results show that the method described in this paper is more accurate and appropriate for estimating industrial hydrogen demand.

ABSTRACT To address proton exchange membrane water electrolyzer (PEMWE) flow field inhomogeneity, this study innovatively proposes a double-spiral circular flow field structure and comparatively analyzes the performance of eight channel-numbered configurations using a three-dimensional non-isothermal two-phase model. Results indicate that the single-channel flow field achieves optimal polarization performance but suffers from an exceptionally high pressure drop (97,674 Pa) and the worst temperature uniformity index (UT) and liquid saturation uniformity index (US), exhibiting significant flow and temperature distribution nonuniformity. Among multi-channel designs, the five-channel configuration demonstrates the best comprehensive performance: compared to the single-channel design, it reduces pressure drop by 86.6% (to 13,087 Pa), improves liquid saturation uniformity by 49%, lowers the temperature uniformity index by 82.6% (UT = 0.00153), decreases average membrane temperature by 9.1 K (to 357.1 K), and enhances the current density uniformity index (Ui) by 32.6%. The three-channel flow field achieves optimal temperature distribution with the lowest UT (0.00153). The study confirms that the five-channel design balances channel quantity and layout, significantly reducing pumping power losses while maintaining voltage efficiency and extending PEMWE lifespan, providing quantitative foundations for high-performance electrolyzer design.

Developing efficient and stable non-precious metal bifunctional catalysts for overall water splitting (OWS) is a promising strategy for industrial hydrogen production. A major challenge is how to balance the distinct active site requirements for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Herein, we report a NiFe layered double hydroxide incorporated with molybdenum (Mo) (NFM0.5-H) for the purpose. During the electrochemical process, Mo leaching generates oxygen vacancies, which facilitate the formation of OER active sites and modulate the interfacial microenvironment to enhance HER kinetics. The integration of atomic incorporation and defect engineering significantly accelerates the overall reaction kinetics. NFM0.5-H delivers outstanding performance for overall water splitting (OWS), achieving low HER and OER overpotentials of 40 and 230 mV, respectively, at 10 mA cm-2 in alkaline media. It drives a low cell voltage of 1.51 V (10 mA cm-2) for OWS and maintains long-term stability at 500 mA cm-2 for over 300 hours. Tests in an alkaline anion exchange membrane water electrolyzer (AEMWE) further confirm the industrial application potential of NFM0.5-H. This work offers new insights into the rational design of advanced OWS catalysts with both high activity and durability.

High-entropy alloys (HEAs) offer a distinctive framework for tailoring surface affinities to reaction intermediates, enabling the design of efficient electrocatalysts. Notably, the heterogeneous interfaces within HEAs play a pivotal role in enhancing both intrinsic catalytic activity and durability, driven by the synergistic interactions among multiple metal atoms. Herein, a heterostructured bifunctional electrocatalyst, CrFeCoNiRu-RuNi (HEA-RuNi), is demonstrated to exhibit exceptional hydrogen and oxygen evolution reaction (HER and OER) activities, delivering overpotentials of 48 and 249 mV for HER and OER, respectively, at a current density of 10 mA cm-2 in alkaline media, and robust stability in an anion exchange membrane water electrolysis device for 200 h. In situ Raman spectroscopy and electrochemical impedance spectroscopy revealed that the unique heterostructure of HEA-RuNi effectively modulates the local Ru microenvironment, redistributing the interfacial water hydrogen bond network within the electrochemical double layer, which facilitates water adsorption and dissociation. Theoretical calculations further unravel that the heterointerface of HEA-RuNi enables to tailoring of the electronic structure of the Ru active site, thus facilitating water dissociation in HER and moderating the adsorption ability of reaction intermediates in OER. The present work provides an insightful understanding of interficial engineering for electrocatalyst design in the field of energy storage and conversion.

Electrocatalytic ozone production (EOP) is a new, environmentally friendly, safe and cost-efficient ozone production technology. The slow kinetics and poor stability of conventional catalysts in the EOP process limit its wide application. Consequently, the development and design of novel EOP catalysts are crucial. There have been few reviews on various types of EOP catalysts. Therefore, this paper reviews recent advances on EOP catalysts, categorized by material types. Additionally, the mechanism of EOP is discussed in depth. Finally, we propose constructive implications for future EOP system development. This paper aims to provide an in-depth analysis of the EOP process, summarize and discuss advances in EOP materials, and establish a reliable foundation for future EOP development.

Electrocatalytic water electrolysis is intrinsically limited by the slow kinetics of the oxygen evolution reaction (OER) at the anodic electrode. The development of highly active and stable catalysts for the OER is both essential and challenging. In this work, we employed porous metal-organic frameworks (MOFs) to synthesize Ru-etched MOF-derived CuCoO2 nanocrystals used as an OER catalyst. The electrochemical test results revealed that the Ru-etched CuCoO2 electrode (Ni@CCORu-3) synthesized via a 3h RuCl3-etching reaction exhibits superior catalytic activity (η10=368.4mV, Tafel slope=81.2mV dec-1) in 1.0M KOH electrolyte. After an 18h OER stability test, the Ni@CCORu-3 exhibited excellent stability with a minimal overpotential degradation of approximately 30mV. This enhancement in OER activity can be attributed to the improved specific surface area and pore structure of the MOF-derived CCORu-3 catalyst, resulting from RuCl3 etching. Furthermore, the electron distribution on the catalyst surface is modulated by Ru species loaded onto the surface. X-Ray photoelectron spectroscopy (XPS) and ultraviolet-visible-near infrared (UV-Vis-NIR) absorption spectra results revealed that RuCl3 etching increases the proportion of active sites and narrows the bandgap of CuCoO2, thereby accelerating electron transfer rates during the OER process and optimizing catalytic activity. This study may provide a novel insight into enhancing the OER performance of CuCoO2 catalysts derived from MOFs.

In contrast to the liquid phase of water, the structural molecular realities of H2O molecules embedded in crystallised salts vary little and can be precisely determined. However, this water, which is neither in the liquid nor in the gas phase, has not yet been used in water electrolysis. Here, we demonstrate that water electrolysis can be achieved without the addition of (liquid) water through experiments with a wide range of hydrated salts and organic solvent suspensions. We obtain an excellent correlation between the position of the FTIR O─H stretch vibration of the hydrated salts and the onset of the OER potential from CV measurements. Together with first-principles density functional theory calculations, we demonstrate that intramolecular bonds in crystallised water can be effectively controlled through choice of the inorganic salt. Targeted manipulation of the bonds in the H2O molecule is a promising new approach to more efficient hydrogen production.

The Recent Trend of Fuel Cells and Water Electrolysis and Their Direction of Technology Development

Development and Evaluation of Large-scale PEM Water Electrolysis and Alkaline Water Electrolysis Systems

The efficient production of hydrogen via acidic water electrolysis is hampered by the sluggish kinetics of the oxygen evolution reaction (OER) and the scarcity of robust bifunctional catalysts. Iridium-based materials have been recognized as promising active sites; however, the atomic utilization should be maximized, and the stability requires further enhancement. This work introduces a support-intensified catalyst design that features covalent Ir-P-Mo linkages for achieving robust water dissociation. Theoretical calculations reveal that the Ir─P─Mo bond enhances hydrogen evolution reaction (HER) activity by optimizing hydrogen adsorption, while the Ir─O─Mo bond is more favorable for OER. Guided by this principle, a catalyst with coexisting Ir-O-Mo and Ir-P-Mo linkages is rationally synthesized, which exhibits exceptional bifunctional performance in acid solution, including low overpotentials of 33mV for HER and 249mV for OER at 10mA cm-2. When configured in a symmetrical two-electrode electrolyzer, it requires only 1.501V to reach 10mA cm-2 and demonstrates remarkable stability for 250 h with minimal voltage degradation. This work verifies the critical role of interfacial bond engineering in developing efficient and durable iridium-based electrocatalysts for practical acidic water splitting.

The development of oxygen evolution reaction (OER) catalysts based on non-noble metals that have high catalytic activity and long-term stability is crucial for the use of an anion exchange membrane water electrolyzer (AEMWE). Here, we report a three-layer composite OER catalyst, NiFe-LDH/CoPi/NF, with the cobalt phosphate (CoPi) interlayer in the middle of nickel foam and a NiFe-LDH nanosheet array. The CoPi interlayer significantly improves the OER catalytic activity as well as the stability. The overpotential required for NiFe-LDH/CoPi/NF to achieve an OER current density of 1000 mA·cm-2 is only 277 mV, and the performance has almost no attenuation for 1000 h of continuous working at 1000 mA·cm-2. The AEMWE using NiFe-LDH/CoPi/NF as an anode reached a current density of 1 A·cm-2 at the cell voltage of only 1.709 V, and it stably operated up to 1200 h. It is found that the CoPi interlayer modulated the morphology of the NiFe-LDH nanosheet arrays and also tuned the electronic structure of the NiFe-LDH. The Ni in NiFe-LDH/CoPi/NF shows a higher valence state, thereby promoting its activity, and also shows a low dissolution rate, thereby promoting its stability.

The design of acidic oxygen evolution reaction (OER) catalysts with controlling defects persists as a pivotal obstacle to achieving sustainable hydrogen production via water electrolysis. In this work, we construct grain boundary-rich structures in ultrathin RuOx nanosheets via codoping with Ni and B (Ni,B-RuOx), resulting in interfacial configurations with atomic-scale defects. This architecture establishes two distinct classes of active sites within the interfacial and lattice regions, enabling precise modulation of dual reaction pathways─namely, the adsorbate evolution mechanism (AEM) and the lattice oxygen mechanism (LOM). Specifically, interfacial sites optimize the adsorption energy barriers of oxygen intermediates, while lattice sites promote the activation and participation of lattice oxygen. The spatially separated synergistic mechanism allows Ni,B-RuOx to simultaneously achieve exceptional catalytic activity (an overpotential of 206.8 ± 1.3 mV at 10 mA cm-2) and long-term stability (>700 h) in 0.5 M H2SO4. Kinetic analyses in proton exchange membrane electrolyzers further demonstrate that the grain boundary-rich structure sustains robust interfacial reaction under harsh operating conditions. This work provides a new paradigm for atomic interface engineering in the design of highly stable acidic OER catalysts, thereby advancing the practical application of green hydrogen production technologies.

The high cost of catalysts remains a major bottleneck for water electrolysis hydrogen production, making the development of cost-effective and efficient non-precious-metal catalysts an urgent priority. In this study, we synthesized selenium vacancy-rich iron selenide (Fe3Se4) through an electro-precipitation method. Combined theoretical calculations and experimental characterization confirm that these selenium vacancies serve as highly efficient active sites, effectively modulating the local electronic structure of Fe centers and optimizing their adsorption behavior toward reaction intermediates. In the oxygen evolution reaction (OER), this defective structure significantly enhances water molecule adsorption and dissociation while minimizing the activation energy barrier of the rate-determining step. Benefiting from these features, the Se-deficient Fe3Se4 catalyst exhibits high OER performance, requiring only 274.8 mV overpotential to achieve 50 mA cm-2 while demonstrating remarkable stability for 100 h at 100 mA cm-2, highlighting its rapid OER kinetics.

Electrocatalytic oxidation of biomass molecules such as ethanol in hybrid alkaline water electrolysis is more thermodynamically favorable and techno-economic attractive to replace conventional pure water electrooxidation to produce green hydrogen. Herein, the flexible and binder-free hollow microtube catalyst arrays of CoS2/CC, Ni0.04Co0.96S2/CC, Fe0.07Ni0.04Co0.89S2/CC, and Fe0.08Ni0.10Co0.82S2/CC were derived from metal-organic framework arrays anchored on carbon cloth (CC). These arrays exhibited favorable performance in electrochemical water oxidation, ethanol oxidation, and hydrogen evolution processes, because of their obvious advantages in high conductivity and long-term stability. The optimized self-supporting Fe0.08Ni0.10 Co0.82S2/CC electrode composed of a 3D hollow porous microtube structure only needs a low potential of 1.412 and 1.267V (vs. RHE) to deliver 10mA cm-2 current density for alkaline water and ethanol oxidation reactions, respectively. Simultaneously, the pure CoS2/CC electrode presents excellent alkaline hydrogen production property among the series self-supporting electrodes with a low overpotential of 188mV at 10mA cm-2. In this work, it is proved that the hybrid water splitting system, using Fe0.08Ni0.10Co0.82S2/CC and CoS2/CC as anode and cathode, respectively, can effectively reduce the cell voltage to 1.479V to deliver 10mA cm-2 with high pure hydrogen generation and high valued potassium acetate generation.

Anion exchange membrane water electrolysis (AEMWE) has become a promising technology for generating hydrogen in a carbon-neutral economy. However, its competitiveness is currently limited by the low durability of AEMWE systems. To increase its durability and to advance its industrial application, this study examines the degradation behavior of a 25 cm2 AEMWE cell utilizing non-precious metal catalysts and pure water feed in a short-term durability test. Polarization curves and electrochemical impedance spectroscopy, along with scanning electron microscopy and energy-dispersive X-ray spectroscopy, are employed to identify factors affecting cell efficiency and stability. The pure-water-fed AEMWE cell exhibits high performance losses and low stability that is mainly related to degradation in the anode and at the interface of anode and membrane. Ionomer degradation, reducing hydroxide ion conductivity, and mechanical stability of the catalyst layer, is identified as the key factor decreasing cell efficiency and stability during pure water operation. The findings aim to guide the development of strategies to enhance cell performance and durability of pure-water-fedAEMWE.

Practical electrolyzer-level hydrogen production, exemplified by alkaline anion exchange membrane (AEM) ones, typically operates at harsh conditions, e.g., high-current densities (> 1 A cm-2) and long-term duration, which present significant challenges for the durability of catalysts. These challenges are amplified in atomically dispersed catalysts due to their weak point-to-point interactions. Here, we present an atom-ordering strategy to fabricate Co triangular orders that enable the activation of the substrate for durable AEM electrolyzers. We demonstrate that Co atoms thermodynamically favor triangular arrangements within the VN lattice, which are successfully synthesized via a photo-induced self-assembly method. This Co-triangular order enables the activation of adjacent V atoms, driving the exponential propagation of active sites for hydrogen production under high currents. Notably, this catalyst exhibits an extended linear region in the Tafel slope and performs stably at a current density of 1 A cm-2. The assembled AEM water electrolyzer achieves a cell voltage of 1.97 V with long-term operational durability. Our work provides a strategy for designing atom-ordered catalysts that strike a balance between activity and long-term stability under industrial operating conditions.

Abstract The development of efficient and stable catalysts for hydrogen production from electrolytic water for multiscenario applications is of great significance to alleviate the energy crisis. Here, highly dispersed PtRu alloy cluster electrocatalysts (PtRu/NCNTs) with ultrasmall particle sizes are constructed by simultaneous in situ reduction method with the help of in situ reduction properties of borane clusters. PtRu/NCNTs achieves significant hydrogen production from electrolytic water in multiple scenarios (full pH environment, real seawater, simulated seawater, and anion‐exchange membrane integration), exceeding the performance of commercial Pt/C catalysts. The interfacial adsorption of H 2 O and the transition behavior of [H] on the Pt and Ru sites in the hydrogen evolution reaction (HER) are observed by in situ attenuated total reflection fourier transform infrared spectroscopy, and density‐functional theory (DFT) calculations revealed that electron transfer from Ru to Pt in the PtRu/NCNTs yielded closer‐to‐zero Gibbs free energies and smaller water‐cleavage energies to enhance the HER activity.

Methanol synthesis is one of the most hydrogen-intensive chemical processes, making its decarbonization a critical step toward climate-aligned chemical production. In this study, Aspen Plus® process simulation and techno-economic assessment (TEA) were applied to evaluate and compare four hydrogen production configurations for natural-gas-based methanol synthesis with capacity of 5,000 tons/day: (i) a conventional partial oxidation (POx)- water-gas shift reaction (WGS) base case, (ii) advanced reforming of methane (ARM) with integrated CO 2 utilization and multi-walled carbon nanotube (MWCNT) co-production, (iii) methane pyrolysis coupled with reverse water–gas shift reaction (RWGS), and (iv) POx supplemented with renewable hydrogen and oxygen from alkaline water electrolysis (AWE). Each configuration was assessed for syngas composition, carbon intensity (CI), capital and operating expenditures, net present value (NPV), internal rate of return (IRR), levelized cost of fuel (LCOF), and marginal abatement cost (MAC). Both ARM and Methane Pyrolysis + RWGS achieved net-negative CI (−0.47 and −0.57 kg CO 2 /kg MeOH, respectively), while AWE + POx reduced CI by 75% compared with the baseline and exhibited the lowest indirect emissions. ARM provided the highest profitability (NPV ≈ $20.2 B, IRR ≈ 118%/year) due to MWCNT revenues, whereas AWE-integrated delivered the lowest LCOF (≈$296/ton) and a negative MAC (≈−$137/ton CO 2 e), representing a cost-saving “no-regrets” decarbonization pathway. Methane pyrolysis and RWGS offered the deepest CO 2 reduction but were more sensitive to natural gas and electricity prices. These results identify clear deployment niches: ARM in regions with robust carbon co-product markets, methane pyrolysis + RWGS where CO 2 supply is abundant and valorization is feasible, and AWE-integrated where low-cost renewable electricity is accessible. Two-way sensitivity maps further delineate viability domains as a function of gas and methanol prices, providing a compact decision-support tool for investors.

The construction of a Pt-based single-atom alloy (SAA) catalyst could concurrently fulfill the demands for low Pt loading and high performance of the cathode of a proton exchange membrane water electrolyzer (PEMWE), but its controllable synthesis remains a challenge. Herein, we report the successful fabrication of carbon shell-encapsulated Pt-doped NiFe single-atom alloy (C@Pt-NiFe SAA) catalysts via a spatial confinement strategy, followed by an investigation of the detailed formation process. As expected, compared with commercial Pt/C, C@Pt-NiFe SAA exhibits enhanced mass activity for the acidic hydrogen evolution reaction (HER). Remarkably, when integrated into PEMWE cathodes, C@Pt-NiFe SAA also outperforms commercial Pt/C. Operando X-ray absorption spectroscopy (XAS) characterization confirms that the low-coordination Pt sites generated in situ during the reaction serve as the main active sites, whereas theoretical calculations confirm the optimized electronic structure and ΔGH* of the Pt single atoms, which jointly contribute to the enhanced HER activity of C@Pt-NiFe SAA. Inspiringly, this spatial confinement strategy can be universally used to prepare other platinum group metal (PGM, PGM = Ru, Rh, Pd, Os, and Ir)-based SAAs. This work not only shows that C@Pt-NiFe SAA is a promising candidate catalyst for use at the cathode of practical PEMWEs but also stimulates research interest in further exploring the promising applications of other PGM-based SAAs in the broad electrocatalytic field.

Activating RuO2 nanofibers through precise Re doping toward promoted alkaline water electrolysis under high current density exceeding 1Acm-2.