Hydrogen spillover offers a promising approach to develop highly active and affordable electrocatalysts for the hydrogen evolution reaction by regulating hydrogen migration and kinetics. Herein, a catalyst composed of osmium nanoparticles supported on zirconium dioxide (Os/ZrO2) is designed and synthesized. The Lewis-acid-rich ZrO2 support not only promotes water dissociation but also triggers hydrogen spillover, thereby optimizing the desorption energetics of hydrogen intermediates. Then, Os/ZrO2 delivers outstanding HER activity in both alkaline and acidic electrolytes, requiring overpotentials of only 16 and 14 mV to reach 10 mA cm-2, surpassing commercial Pt/C and Os/C. Mechanistic studies have confirmed the occurrence of hydrogen spillover, whereby hydrogen intermediates migrate from the Os nanoparticles to the ZrO2 surface, effectively tuning the adsorption/desorption kinetics and leading to significantly enhanced HER performance. Furthermore, in an anion-exchange membrane electrolyzer, Os/ZrO2||RuO2 achieves a low voltage of 1.82 V at 1 A cm-2 and maintains stable operation, translating to a hydrogen production cost of $0.97 per gasoline gallon equivalent. This work presents an effective strategy for designing high-performance HER catalysts through hydrogen spillover engineering, providing a feasible route for enhanced electrocatalytic systems.

The reductive transformation of persistent halogenated alkanes, such as 1,2-dichloroethane (1,2-DCA), presents a long-standing challenge. Achieving rapid cleavage of the inert C-Cl bond of 1,2-DCA requires forceful electron transfer, but this often accelerates competing hydrogen evolution and ethylene overhydrogenation, undermining the electron efficiency, product selectivity, and long-term stability. Here, we report a mechanochemically engineered zero-valent iron (ZVI) functionalized with electron-localized O-CoN4 sites that reconciles this conflict of interest, using cobalt tetramethoxyphenylporphyrin as the Co precursor. This architecture maximizes the utilization of Co atoms, resulting in a Co-normalized dechlorination rate 2 to 40 times superior to those of reported benchmarked ZVIs. Spectroscopic and computational analyses reveal that electron accumulation at the Co center reduces the C-Cl bond cleavage barrier while creating proton-limited microenvironments that suppress hydrogen evolution and stabilize ethylene against further reduction. Consequently, the material achieves a 144-fold improvement in electron efficiency and a 65-fold enhancement in ethylene selectivity compared to pristine ZVI. Crucially, the system maintained activity and selectivity under continuous-flow operation and 100 day aging in real groundwater, consistently reducing 1,2-DCA below regulatory thresholds. This work provides a mechanochemically engineered strategy for the selective dehalogenation of halogenated alkanes, advancing sustainable remediation of halogenated pollutants.

The sluggish hydrogen evolution reaction (HER) in alkaline media is fundamentally limited by the high energy barrier of H2O dissociation, which is strongly governed by the orientation and hydrogen-bond environment of interfacial H2O molecules. Here, we reported a heterostructured electrocatalyst comprising PtOx nanoclusters anchored on NiO (PtOx/NiO) that overcomes this limitation by regulating the interfacial H2O configuration. Combined in-situ experimental and theoretical investigations revealed that PtOx/NiO established a strengthened dipole field, which induced a preferential H-down orientation of interfacial H2O, thereby lowering the H2O dissociation barrier. Meanwhile, partially oxidized Pt sites optimize hydrogen intermediate binding, increasing surface proton availability and facilitating subsequent HER. As a result, the PtOx/NiO delivered outstanding HER performance in alkaline electrolyte, requiring only 27 mV overpotential at 10 mA cm-2. This work establishes interfacial dipole engineering as an effective strategy for accelerating H2O activation, offering new mechanistic insight and a generalizable framework for designing high-efficiency alkaline HER electrocatalysts.

Photo-assisted electrochemical (PAEC) water splitting represents a promising approach for efficient hydrogen and oxygen generation under solar illumination. However, catalyst delamination from the working electrode and blockage of electrochemically active sites due to gas bubble adhesion significantly hinder the performance. To overcome these issues, a 2D photocatalyst, graphitic carbon nitride (g-C3N4), was incorporated into a robust, highly bubble-repellent composite coating on a porous nickel foam (NF) substrate. The resultant composite prevents g-C3N4 delamination from the electrode surface, while its intrinsic superaerophobicity enables rapid detachment of evolved gas bubbles. Furthermore, photoexcited charge carriers in g-C3N4 and its photothermal enhancement effectively assist water-splitting reactions. Compared with conventional strategies involving direct photocatalyst coating on NF, with or without an additional bubble-repellent layer, the proposed composite demonstrates a significantly improved PAEC performance. It exhibits a larger electrochemically active surface area, reduced overpotentials for both hydrogen and oxygen evolution reactions, and significantly improved gas evolution yields-enhancing hydrogen and oxygen production by 51% and 44%, respectively, at reduced applied potentials relative to bare NF under simulated solar illumination. This simple yet effective approach harnesses the cooperative influence of photoactive charge stimulation, localized photothermal enhancement, and optimized bubble dynamics in achieving stable, energy-efficient photo-assisted water splitting.

Electrochemical nitrate reduction to ammonia (NO3RR) is a promising pathway for nitrogen recycling but remains hindered by complex multistep kinetics and severe competition from the hydrogen evolution reaction. Coupling NO3RR with the sulfide oxidation reaction (SOR) offers an energy-efficient alternative by simultaneously enabling dual-pollutant remediation with value-added products. Herein, we report an in situ exsolution strategy to construct a tandem electrocatalyst composed of exsolved Ag nano-islands (NIs) anchored on a high-entropy perovskite oxide matrix (Ag-LaSrAgFeCoOx). The structural complexity and abundant oxygen vacancies (Ov) of the LaSrAgFeCoOx synergistically interact with the exsolved Ag NIs, creating spatially and functionally distinct active sites. As a result, the Ag-LaSrAgFeCoOx catalyst achieves high NH4 + Faradaic efficiency of 97.6% and yield rate of 0.35mmol h-1cm-2. In situ characterization and theoretical calculations reveal a relay catalytic mechanism in which Ag sites of Ag NIs preferentially activate NO3 -, while Ov-rich LaSrAgFeCoOx promotes intermediates hydrogenation and NH3 desorption, alongside efficient hydrogen supply. Moreover, the bifunctional Ag-LaSrAgFeCoOx enables energy-efficient NO3RR||SOR coupling, delivering a positive open-circuit potential of 557mV and stable co-production of ammonia and sulfur. This work highlights high-entropy materials as a powerful platform for tandem electrocatalysis in complex coupled reactions.

The manipulation of the electrocatalyst nanoarchitecture, particularly transition metal compounds, regarding size, shape, facets, and composition, significantly enhances the electrocatalytic activity in energy transformations. This study introduces a novel methodology for the precipitation of mesoporous nanoparticles of nickel tungstate (meso-NiWO4) using direct chemical deposition from a template of Brij®78 surfactant liquid crystal. Physicochemical analyses revealed the formation of amorphous meso-NiWO4 nanoparticles with dual sizes of 10 ± 3 and 120 ± 8 nm and a specific surface area of 34.2 m2/g, exceeding that of nickel tungstate deposited in the absence of surfactant (bare-NiWO4, 4.0 m2/g). The meso-NiWO4 nanoparticles exhibit improved electrocatalytic stability, reduced charge-transfer resistance (Rct = 1.11 ohm), and a current mass activity of ~365 mA/cm2 mg at 1.6 V vs. RHE during the electrolysis of urea in alkaline solution. Furthermore, by employing meso-NiWO4 in a two-electrode urea electrolyzer, a remarkable 4.8-fold increase in the cathodic hydrogen concurrent production rate was achieved (373.40 µmol/h at a bias potential of 2.0 V), compared to that of the bare-NiWO4 catalyst. The exceptional urea oxidation electroactivity and the enhanced hydrogen evolution rate arise from substantial specific surface area and mesoporous structure, facilitating effective charge transfer and mass transport through the meso-NiWO4 catalyst. Using the surfactant liquid crystal template for electrocatalyst synthesis enables a one-pot deposition of diverse nanoarchitectures and compositions with high surface area at ambient conditions for an improved electrocatalytic and hydrogen green production process.

HighlightsCompared to the 1D planar Janus electrode, the 3D curved surface Janus electrode exhibits a significant advantage in both electrolysis and bubble manipulation.The large-area 3D Janus structure electrode operates stably and efficiently for an entire week without any performance degradation.The 3D Janus electrode can optimize its geometric dimensions to enhance the efficiency of unidirectional bubble manipulation.The chemical deposition process allows for the customization of hydrogen evolution catalysts’ attachment to the electrode surface.The superaerophilic-modified Janus membrane enables unidirectional bubble transport within 16 ms.

In recent years, flow batteries have emerged as a crucial technological solution for large-scale energy storage, leveraging their unique power-capacity decoupling characteristics and long cycle life to demonstrate significant potential in applications such as renewable energy integration and grid frequency regulation. Based on differences in electrolyte systems, mainstream flow battery technologies are primarily categorized into three types: all-vanadium redox flow batteries (VRFBs), iron-chromium redox flow batteries (ICFBs), and zinc-based redox flow batteries (ZRFBs). However, each of these technologies faces critical challenges in practical commercialization: VRFBs are constrained by cost pressures due to fluctuations in vanadium resource prices and relatively low energy efficiency; ICFBs require urgent solutions to issues such as hydrogen evolution side reactions at the negative electrode and the sluggish kinetic responses of the Cr3+/Cr2+ redox couple; while ZRFBs grapple with safety concerns such as zinc dendrite growth and morphology instability. To overcome these technical bottlenecks, extensive innovative research has been conducted in key materials (electrodes, ion-exchange membranes, electrolytes). Against this backdrop, this paper systematically reviews recent advances in the modification and optimization of flow battery technologies and conducts an extended discussion on the emerging organic redox flow batteries in recent years.

Boosting Alkaline Hydrogen Evolution via Synergistic Reverse Hydrogen Spillover and Metal–Support Interactions in Ni–Ru Alloy Clusters on Nitrogen-Doped Carbon

A combination of semiconductors with noble metal nanoparticles is an effective way to improve photocatalytic hydrogen evolution performance via the plasmonic effect by near-field enhancement and hot electron injection. The effectiveness of this approach to organic semiconductors is often compromised by an inefficient electron transfer process at the metal-polymer interface that limits hot electron utilization. Herein, we rationally designed a novel pyrene-sulfone polymer (PSP) composite system that enables firm anchoring of gold nanospheres through electrostatic interactions and coordination effects, thereby establishing efficient pathways for plasmon-induced charge transfer. The size and loading of gold nanospheres were systematically tuned to optimize photocatalytic performance. Our investigation reveals that PSP combined with 8 wt.% 60nm gold nanospheres exhibited the optimal hydrogen production rate of 72.41mmol h-1 g-1, 4.6 fold of that for pure PSP (∼15.66mmol h-1 g-1). In situ XPS, ultrafast transient absorption spectroscopy, and temperature-dependent PL measurements confirm that the synergetic effect of reduced exciton binding energy and hot electron injection effectively promotes carrier generation for the photocatalytic process.

High-entropy oxides (HEOs) emerge as versatile electrocatalysts due to their tunable compositions, defect-rich structures, and robust stability. In this study, non-equimolar (VCrMnFeCo)O HEO microstructures were synthesized via mechanical alloying, a scalable and cost-effective route for catalyst design. When evaluated for hydrogen evolution reaction (HER), these materials exhibited excellent activity and durability in both commercial alkaline electrolyte (6m KOH) and low-alkaline seawater (1m KOH). While 6m KOH is widely employed in commercial alkaline water electrolysis (AWE), catalyst stability under such concentrated conditions remains a critical challenge. Similarly, seawater electrolysis is hindered by chloride-induced corrosion, making durability a key bottleneck. The developed catalyst exhibited low HER overpotentials and high stability during the accelerated durability test (ADT) for 5000 CV cycles. A detailed structural analysis of recovered catalysts after ADT indicated in situ reduction and redistribution of elements under operational conditions that resulted in an enhancement in activity during continuous electrocatalysis cycling. This study establishes mechanically alloyed HEOs as promising candidates for sustainable hydrogen generation, bridging fundamental materials design with practical electrolysis applications in freshwater and seawater systems.

Harnessing hot electron transfer (HET) at plasmonic-semiconductor interfaces is a promising route to modulate charge carrier dynamics toward solar energy-driven water splitting for hydrogen generation. Popular semiconductor photocatalysts driving solar-to-hydrogen conversion, such as FeVO4, suffer from limited visible light absorption, electron-hole recombination, and aqueous instability, often seeking band-gap engineering or cation doping to improve their catalytic prowess. In this first-of-its-kind comprehensive study, we demonstrate a sequentially optimized procedure to obtain one-dimensional (1D) FeVO4 that is integrated with plasmonic nanoparticles (PNPs) to address these limitations. Anchored on the surface of the semiconductor, PNPs generate hot electrons upon visible light irradiation, that are then transferred to FeVO4. Finite-difference time-domain simulations verify the electromagnetic field distribution around the FeVO4-PNP. Additionally, Au, Au-urchin, Ag, and Au+Ag NPs were used to understand the effect of varying sizes, shapes, and plasmonic metals on the photocatalytic efficiency of FeVO4. Circularly polarized photon-triggered asymmetric hot carrier injection (from Au, Au-urchin, Au+Ag) and plasmon-induced resonance energy transfer (from Ag) reveal voltage-dependent interfacial dynamics that govern charge separation and hydrogen evolution efficiency. The experimental data was used to train a generative reinforcement learning (GRL)-based machine learning model to predict the optimum parameters for tunable band gaps and applied bias photon-to-current efficiency. This study thus lays the foundation for determining appropriate combinations of PNPs and other semiconductor materials for photoelectrochemical (PEC) applications.

The development of bifunctional electrocatalysts that efficiently operate for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in a single electrolyte under high current density remains a critical challenge toward applied overall water splitting. Herein, we designed a robust and microporous Co(II)-based nonpenetrating metal-organic framework (MOF) via juxtaposition of redox-active naphthalenediimide linker and π-electron rich C2-symmetric dicarboxylate ligand that features in situ-generated [Co2(COO)4] chain and exhibits high thermo-chemical stability. The efficient charge-mediating architecture upon interface engineering with conductive nickel foam (NF) delivers remarkable bifunctional water splitting activity in an alkaline medium (1 M KOH), achieving an industrially relevant current density of 100 mA·cm-2 with low overpotentials of 313 mV (OER) and 263 mV (HER). Importantly, rapid reaction kinetics, minimal charge-transfer resistance, and >95% Faradaic efficiency outperform the majority of contemporary as well as benchmark materials. The catalyst demonstrated excellent electrochemical durability in both water oxidation and reduction reactions for over 40 h and retains its structural and morphological attributes after prolonged chronoamperometric operation, demonstrating high-performance water splitting. Performance comparison with an isostructural Cd-MOF analogue confirms the essential contribution of ligand-metal synergism in the Co-MOF for much enhanced redox articulation and electrocatalysis. When deployed as both electrodes, the bifunctional MOF/NF system efficiently catalyzes overall water splitting with only 1.678 V cell voltage at 10 mA·cm-2, marking it among the leading MOF-based electrocatalysts. The findings highlight the pivotal role of ligand-metal cooperativity and hierarchical interface engineering in boosting the electrochemical efficacy of MOF catalysts and provide a promising strategy in designing next-generation bifunctional electrocatalysts for sustainable energy applications.

Artificial N2 reduction offers a sustainable approach to green NH3 synthesis, but the practical implementation is challenged by N2 activation and competing hydrogen evolution. Photoelectrochemical nitrate and nitrite (NOx-, x = 2 and 3) reduction with favorable thermodynamics represents a promising alternative for NH3 production, provided that NOx- can be supplied from the atmosphere. Here, through leveraging water microdroplet chemistry and dynamic photoelectrode-electrolyte interface engineering, we report a tandem air-NOx--NH3 conversion system that integrates catalyst-free N2 oxidation with pulsed photoelectrochemical NOx- reduction (mNOR-pPNOxR). The system achieves efficient and selective NH3 production with a yield rate of 24.5 μmol cm-2 h-1 at -0.2 VRHE, which are two to three orders of magnitude higher than conventional photo/electrocatalytic N2 fixation. This study introduces insights for decentralized, on-demand ammonia production from air and water and broadens horizons of microdroplet chemistry and pulse strategy for sustainable chemical manufacturing.

ABSTRACT The formation of metal–hydrogen intermediates (M─H*) is critical for the alkaline hydrogen evolution reaction (HER), but is kinetically hindered by the energy‐intensive water dissociation. Here, we report a distinct pathway in the model catalyst of Pt nanoparticles loaded on TiH 1.924 (Pt/TiH 1.924 ), which directly generates Pt─H* by transferring lattice hydrogen from TiH 1.924 to Pt catalytic sites, while the lattice hydrogen can be dynamically replenished by the electrolyte spontaneously. This pathway decouples Pt─H* formation from water dissociation at a significantly lower energy barrier, as evidenced by operando differential electrochemical mass spectrometry and in situ Raman spectroscopy. The continuous hydrogen supply from the hydride support enables the Pt/TiH 1.924 catalyst to achieve a 35.6‐fold higher mass activity than Pt/C at 100 mV overpotential. Moreover, in an anion exchange membrane water electrolyzer with Pt/TiH 1.924 as the cathode, the cell voltage only requires 1.76 V at a current density of 1 A cm −2 , and the device can operate stably for over 1000 h under this current density. This work proposes a lattice hydrogen‐mediated mechanism to boost alkaline HER and other electrochemical processes constrained by slow M─H* formation, by decoupling Pt─H* production from water dissociation using metal hydride supports.

The ionic liquids are increasingly used as versatile media capable of reshaping the electrochemical environment for hydrogen production. Their wide electrochemical windows, thermal stability, and customizable solvation structures enable these liquids to tailor the electrode–electrolyte interface in such a way that the traditional alkaline and polymer-membrane systems cannot. These features allow for reductions in the hydrogen evolution overpotentials, improved catalyst stability, and effective suppression of gas crossover, positioning the ionic liquids as promising components for advanced electrolysis systems. Despite these benefits, their broader deployment remains constrained by certain challenges. The elevated viscosity and associated mass-transport limitations complicate the cell design and energy efficiency, whereas the cost and long-term stability of many ionic liquids limit their competitiveness in industrial hydrogen production. Also, the hydrolysable anions and other reactive species increase the burden, particularly in environments where moisture and anodic potential are present. As a result, the ionic liquids electrolysis has its most promising prospects in niche and hybrid configurations like the renewable integrated systems and configurations where the tailored interfacial chemistry and long operational lifetimes outweigh the investment cost and maintenance requirements. Future progress will depend on the development of greener, task-specific ionic liquids with improved stability and lower synthesis costs, alongside hybrid electrolyte designs that balance the unique interfacial benefits of ionic liquids with the practicality of aqueous systems. Advancing these materials from laboratory research to large-scale sustainable hydrogen production will require coordinated advances in the materials compatibility, device and infrastructural architecture, and techno-economic optimization.

Efficient and stable photocatalytic water splitting catalysts based on platinum‐free nonprecious metals offer a promising approach to solar‐driven hydrogen production. Here, we synthesized a covalent organic framework (COF) featuring a trinuclear copper cluster (Cu 3 ‐BPY‐COF) and constructed a platinum‐free bimetallic photocatalyst (Cu 3 ‐BPY‐COF(Zn)) through the coordination of Zn 2+ via bipyridine. Cu 3 ‐BPY‐COF(Zn) achieves a hydrogen production rate of 23.04 mmol g −1 h −1 under visible light ( λ > 420 nm), which is a significant improvement over unmodified Cu 3 ‐BPY‐COF (11.60 mmol g −1 h −1 ), and ranks among the best nonprecious metal photocatalysts up to now. The catalyst maintains performance stability for over 32 h with an apparent quantum efficiency of 15.2%. Experimental results and theoretical calculations suggest that the Cu 3 cluster serves as an efficient electron transfer pathway, while Zn 2+ coordination optimizes the electronic structure of the bipyridine ligand, facilitating charge separation and migration. The synergistic effect of Cu 3 –Zn promotes H 2 production by modulating the adsorption free energy of H intermediates, enabling highly efficient proton reduction and thereby achieving high HER activity. This study presents a novel approach for designing platinum‐free bimetallic photocatalysts based on COF for efficient hydrogen production.

Stray currents pose a significant threat to the structural health and resilience of subway shield tunnels through the destructive effects of electrochemical corrosion, which is broadly recognized as one of the main obstacles to ensuring the sustainability of urban rail transit systems. Environmental humidity can lead to variations in the pore water saturation of concrete structures. In the coupled environment of stray currents and pore water saturation, this condition exacerbates the corrosion of reinforced concrete, shortening its service life and jeopardizing the normal operation of subway systems. Given this, a combined study is carried out to explore the effect of pore water saturation on stray current corrosion of reinforced concrete through FEM-based simulation and experiment tests. The effect of pore water saturation on stray current corrosion is studied by varying applied potential and porosity. The study validates the influence of concrete porosity and voltage on the control ranges of pore water saturation corresponding to the various stages of stray current corrosion in reinforced concrete. Based on the simulation and experimental results, it is concluded that, under the same voltage conditions, an increase in the porosity of the reinforced concrete correlates with a greater severity of corrosion as pore water saturation increases. As the applied voltage increased from 2 V to 10 V, the pore water saturation range for iron oxidation shrank from 0–0.6 to 0–0.4, while the hydrogen evolution range expanded from 0.7–1 to 0.5–1. Pore water saturation influences the control mechanisms of electrochemical corrosion at various stages in reinforced concrete. Moreover, under each control mechanism, the control ranges of pore water saturation corresponding to the corrosion stages demonstrate sequential trends of contraction, movement towards lower saturation regions, and expansion as the applied voltage increases. The findings of the study contribute to the understanding of the intrinsic mechanisms underlying the service life extension of buried foundation structures.

Comprehensive strategy through regulating specific atomic orbitals of electrocatalytic sites by heteronuclear double-atom doping for improving alkaline hydrogen evolution reaction.

Regulating the d-band center of tungsten‑molybdenum bimetallic alloys via incomplete carbon coating for enhanced proton dissociation and the photocatalytic hydrogen evolution of transition metal sulfides.