Crystalline Lattice-Confined Atomic Pt in Metal Carbides to Match Electronic Structures and Hydrogen Evolution Behaviors of Platinum

Mitigating Strain Localization via Stabilized Phase Boundaries for Strengthening Multi-Principal Element Alloys

Multi-principal element alloys (MPEA) demonstrate exceptional stability during rapid solidification, making them ideal candidates for additive manufacturing and other high-design-flexibility techniques. Unexpectedly, MPEA failure often mimics that of conventional metals, with strain localization along phase or grain boundaries leading to typical crack initiation. Most strategies aim at reducing strain localization either suppress the formation of high-energy sites or dissipate energy at crack tips to enhance toughness, rarely achieving a synergy of both. Inspired by the microstructure of mouse enamel, nanoscale body-centered cubic (BCC) and face-centered cubic (FCC) phases into MPEAs are introduced, stabilized at phase boundaries to provide ample plastic space for dislocation-mediated deformation. This approach overcomes the local hardening limitations of nanoscale alloys and harmonizes traditional toughening mechanisms-such as crack deflection, blocking, and bridging-to mitigate strain localization. These mechanisms impart the alloy with ultra-high tensile strength (≈1458.1 MPa) and ductility (≈21.2%) without requiring heat treatment. Atomic calculations reveal that partial atomic plane migration drives continuous dislocation transfer across phases. This study uncovers fundamental but latent mechanical mechanisms in MPEAs, advancing understanding of ultra-strong bioinspired alloys.

Manipulating Interfacial Water Via Metallic Pt1Co6 Sites on Self-Adaptive Metal Phosphides to Enhance Water Electrolysis

Metallizing active sites to control the structural and kinetic dissociation of water at the catalyst-electrolyte interface, along with elucidating its mechanism under operating conditions, is a pivotal innovation for the hydrogen evolution reaction (HER). Here, a design of singly dispersed Pt-Co sites in a fully metallic state on nanoporous Co2P, tailored for HER, is introduced. An anion-exchange-membrane water electrolyzer equipped with this catalyst can achieve the industrial current densities of 1.0 and 2.0 A cm-2 at 1.71 and 1.85 V, respectively. It is revealed that the singly dispersed Pt-Co sites undergo self-adaptive distortion under operating conditions, which form a Pt1Co6 configuration with a strongly negative charge that optimizes reactant binding and reorganizes the interfacial water structure, resulting in an improved concentration of potassium (K+) ions in the closest ion plane. The K+ ions interact cooperatively with H2O (K·H2O), which strengthens the Pt-H binding interaction and facilitates the polarization of the H─OH bond, leading to improved HER activity. This study not only propels the advancement of cathodic catalysts for water electrolysis but also delineates a metallization strategy and an interface design principle, thereby enhancing electrocatalytic reaction rates.

Anti-Sintering Ni-W Catalytic Layer on Reductive Tungsten Carbides for Superior High-Temperature CO2 Reduction

The reverse water-gas shift (RWGS) reaction stands out as a promising approach for selectively converting CO2 into CO, which can then be upgraded into high-value-added products. While designing high selectivity and stability catalysts for RWGS reaction remains a significant challenge. In this study, an efficient and ultra-stable Ni-W catalytic layer on reductive WC (NiAWC) is designed as an anti-sintering catalyst for superior high-temperature RWGS reaction. Benefiting from the unique structures, the NiAWC catalyst exhibits exceptionally high performances with a CO production rate of 1.84 molCO gNi -1 h-1 and over 95% CO selectivity, maintaining stability for 120 h at 500 °C. Even after 300 h of continuous testing at 600 °C and five aging cycles at 800 °C, the activity loss is only 0.34% and 0.83%, respectively. Unlike the conventional mechanism in RWGS reaction, it is demonstrated that the Ni-W limited coordination can stabilize the Ni sites and allow a pre-oxidation of Niδ+ by CO, which produces an O* electronic reservoir and hinders the charge transfer from Ni to W-O, thereby avoiding the dissolution of Ni atoms. The design of new, efficient, and selective catalysts through metal-substrate synergistic effects is suggested to offer a promising path to engineering superior thermal catalysts.

Oxygen spillover on supported Pt-cluster for anti-CO-poisoning hydrogen oxidation

Reducing Pt loading in the anodic hydrogen oxidation reaction (HOR) and concurrently increasing mass activity and CO tolerance are essential for advancing proton exchange membrane fuel cells (PEMFCs). Here, an electrocatalyst of 1.7 wt% Pt clusters loaded on a hollow bowl-like W3O/WC heterostructure is designed to increase the anti-CO-poisoning HOR. Due to its unique electron delocalization effect, the W3O/WC heterostructure serves as a warehouse to share electrons with Pt; this simultaneously lowers the HOR barrier and accumulates the hydroxyl radicals (•OH) to accelerate CO oxidation. The Pt‒O bond originating from the oxygen spillover effect of W3O promotes hydrogen and CO oxidation, whereas the lattice‒O consumed in W3O replenished through water dissociation. The resultant electrocatalyst exhibits mass activity of 469 A g‒1 at 50 mV and anti-toxicity even at 2000 ppm CO. The PEMEC delivers a peak power density of 1.63 W cm‒2 and maintains considerable anti-CO poisoning performance.

Advanced Fabrication of Graphene-Integrated High-Entropy Alloy@Carbon Nanocomposites as Superior Multifunctional Electrocatalysts

High entropy materials exhibit unparalleled reactivity and tunable electrochemical properties, putting them at the forefront of advances in electrocatalysis for water splitting. Their various interfaces and elements are purposefully engineered at the nanoscale, which is essential to enhancing their electrochemical characteristics. The exceptional catalytic efficiency observed in graphene-coated nanoparticles (NPs) with an inner high-entropy alloy (HEA) (HEA@C) is a result of the combined action of several metallic constituents. However, increasing catalytic efficiency is still a very difficult task, particularly when it comes to obtaining precise control over the composition and structure via efficient synthesis techniques. HEA@C NPs exceptional reactivity and adaptable electrochemical characteristics allow them to perform better in slow oxygen evolution (SOE) activities. The novel multilayer graphene-enhanced HEA CoNiFeCuV@C NPs electrocatalyst presented in this work is carbon-based, and transmission electron microscopy (TEM) investigations verify its efficacy. The efficiency of the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR) is greatly increased by this electrocatalyst. The electrocatalytic performance of the core-shell HEA CoNiFeCuV@C NPs is remarkable for HER, OER, and ORR, even though its highly stressed lattice has structural flaws. These catalysts reach a half-wave potential of 0.87 V in 0.1 M HClO4 at a moderate current density of 10 mA cm-2, with HER and OER onset potentials of 20 and 259 mV, respectively. Using cyclic voltammetry scans, the study delves deeper into the material's evolution by examining its morphology, chemical state, and elemental makeup both before and after activation. In addition to introducing novel electrocatalysts, this study significantly enhances our understanding of the deliberate synthesis of multicomponent intermetallic high-entropy alloys.

Negative-Valent Platinum Stabilized by Pt─Ni Electron Bridges on Oxygen-Deficient NiFe-LDH for Enhanced Electrocatalytic Hydrogen Evolution

The unique hydrogen adsorption characteristics of negatively charged platinum play a crucial role in enhancing the electrocatalytic hydrogen evolution reaction. However, atomically dispersed Pt atoms are typically anchored to the support through non-metallic atom bonds, resulting in a high oxidation state. Here, atomically dispersed Pt atoms are anchored in oxygen-deficient NiFe-LDH. Electron transfer between Pt and NiFe-LDH occurs primarily through Pt─Ni bonds rather than the conventional Pt─O bonds. Oxygen vacancies in the NiFe-LDH promote additional electron transfer from Ni to Pt, thereby reducing the valence state of Pt and enhancing hydrogen adsorption. Meanwhile, the elevated valence state of Ni increases the catalyst's hydrophilicity and reduces the energy barrier for hydrolysis dissociation. This catalyst demonstrates remarkably low overpotentials of 4 and 9 mV at 10 mA cm-2 in 1 m KOH and 1 m KPi, respectively. Additionally, its mass activity is 51.5 and 23.7 times higher that of Pt/C, respectively. This study presents a novel strategy for enhancing electrocatalytic performance through the rational design of coordination environments and electronic structures in supported metal catalysts.

Nanoconfinement Effects in Electrocatalysis and Photocatalysis

Recently, the enzyme-inspired nanoconfinement effect has garnered significant attention for enhancing the efficiency of electrocatalysts and photocatalysts. Despite substantial progress in these fields, there remains a notable absence of comprehensive and insightful articles providing a clear understanding of nanoconfined catalysts. This review addresses this gap by delving into nanoconfined catalysts for electrocatalytic and photocatalytic energy conversion. Initially, the effect of nanoconfinement on the thermodynamics and kinetics of reactions is explored. Subsequently, the primary and secondary structures of nanoconfined catalysts are categorized, their properties are outlined, and typical methods for their construction are summarized. Furthermore, an overview of the state-of-the-art applications of nanoconfined catalysts is provided, focusing on reactions of hydrogen and oxygen evolution, oxygen reduction, carbon dioxide reduction, hydrogen peroxide production, and nitrogen reduction. Finally, the current challenges and future prospects in nanoconfined catalysts are discussed. This review aims to provide in-depth insights and guidelines to advance the development of electrocatalytic and photocatalytic energy conversion technology by nanoconfined catalysts.

Confined Flash Pt1/WCx inside Carbon Nanotubes for Efficient and Durable Electrocatalysis

Exploiting cost-effective hydrogen evolution reaction (HER) catalysts is crucial for sustainable hydrogen production. However, currently reported nanocatalysts usually cannot simultaneously sustain high catalytic activity and long-term durability. Here, we report the efficient synthesis and activity tailoring of a chainmail catalyst, isolated platinum atom anchored tungsten carbide nanocrystals encapsulated inside carbon nanotubes (Pt1/WCx@CNTs), by confined flash Joule heating technique. The instantaneous carbothermal reduction reaction enables the millisecond formation of Pt1/WCx nanostructures from CNT-encapsulated polyoxometalates, where nanotubes serve as both heating conductors and robust chainmails. The Pt1/WCx@CNTs exhibit prominent catalytic performance toward acid HER with a low overpotential of 45.2 mV at 10 mA cm-2 and long-term durability over 500 h of continuous running. Mechanism studies reveal the strong metal-support interaction on Pt1/WCx optimizes the charge redistribution at the Pt1-W2C interface and the hydrogen adsorption/desorption behavior. This study offers a potential avenue for ultrafast and activity-controllable synthesis of highly stable single-atom catalysts.

Design of RuOx Electrocatalysts Containing Metallic Ru on the Surface to Accelerate the Alkaline Hydrogen Evolution Reaction

The development of water splitting technology in alkaline medium requires the exploration of electrocatalysts superior to Pt/C to boost the alkaline hydrogen evolution reaction (HER). Ruthenium oxides with strong water dissociation ability are promising candidates; however, the lack of hydrogen combination sites immensely limits their performance. Herein, we reported a unique RuOx catalyst with metallic Ru on its surface through a simple cation exchange method. We demonstrated that the formation of metallic Ru on RuOx greatly enhances the interaction between the catalyst and adsorbed hydrogen (*H), resulting in extremely high HER activity in alkaline media. Moreover, we proposed the potential of zero charge (Epzc) as a descriptor of ruthenium-base catalysts for alkaline HER for the first time and revealed that the existence of metallic Ru optimizes the Epzc of RuOx toward the hydrogen region. As a result, the designed RuOx catalyst achieves an overpotential of only 18 mV at the current density of 10 mA cm-2. Furthermore, RuOx requires 1.80 V to reach 800 mA cm-2 in the anion exchange membrane water electrolyzer, outperforming the benchmark Pt/C.

Metallic PtC monolayer as a promising hydrogen evolution electrocatalyst

Reasonable design of hydrogen evolution reaction (HER) electrocatalysts with low Pt loading and excellent catalytic performance is a key challenge in finding efficient and cost attractive catalysts. Pt with its unique d-electrons provides new opportunities for the development of HER catalysts when it forms compounds with highly earth-abundant C. Herein, we focused on designing highly efficient catalysts composed of Pt and C elements using first-principles structure search simulations, identifying four stability PtCx monolayers. The novel PtC monolayer with a zigzag C chain not only possesses lower Pt loading but also shows inherent metallicity. Meanwhile, its H2O adsorption and dissociation abilities are efficient and facile. The HER activity of the PtC monolayer is comparable to that of commercial Pt, with desirable ΔGH* values and larger exchange current density, which are mainly attributed to lower charge donation of Pt, larger occupation of Pt PDOS at the Fermi level, and paired electrons of the zigzag C chain. Moreover, its excellent HER activity can be maintained even at high H coverage under strain and solvent effect. All these attractive properties render the PtC monolayer an appropriate HER catalyst.

Enhancing electrocatalytic hydrogen evolution via engineering unsaturated electronic structures in MoS2

The search for efficient, earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) has identified unsaturated molybdenum disulfide (MoS2) as a leading candidate. This review synthesises recent advancements in the engineering of MoS2 to enhance its electrocatalytic properties. It focuses on strategies for designing an unsaturated electronic structure on metal catalytic centers and their role in boosting the efficiency of the hydrogen evolution reaction (HER). It also considers how to optimize the electronic structures of unsaturated MoS2 for enhanced catalytic performance. This review commences with an examination of the fundamental crystal structure of MoS2; it elucidates the classical unsaturated electron configurations and the intrinsic factors that contribute to such electronic structures. Furthermore, it introduces popular strategies for constructing unsaturated electronic structures at the atomic level, such as nanostructure engineering, surface chemical modification and interlayer coupling engineering. It also discusses the challenges and future research directions in the study of MoS2 electronic structures, with the aim of broadening their application in sustainable hydrogen production.

Hydrogen Spillover-Bridged Interfacial Water Activation of WCx and Hydrogen Recombination of Ru as Dual Active Sites for Accelerating Electrocatalytic Hydrogen Evolution

Tungsten carbide (WCx) is a promising alternative to platinum catalysts for hydrogen evolution reaction (HER). However, strong tungsten-hydrogen bond hinders hydrogen desorption while favoring H+ reduction, thus limiting HER kinetics. Inspired by the phenomenon of hydrogen spillover in heterogeneous catalysis, a ruthenium (Ru) doped-driven activated hydrogen migration from WCx surface to Ru is reported. This approach achieved high activity with an ultralow overpotential of 9.0 mV at 10 mA·cm-2 and superior stability at an industrial-grade current density of 1.0 A·cm-2 @ 1.65 V. In situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and operando electrochemical impedance spectra revealed that this exceptional hydrogen production-which surpasses that of previously reported Pt/C catalysts-is attributable to the outstanding ability of WCx to induce water dissociation and hydrogen spillover from WCx to Ru surface. During the HER process, the rigid interfacial water network negatively affected the HER efficiency under alkaline conditions. The WCx sites disrupted this rigid structure, facilitating the contact between activated hydrogen (H*) and WCx sites. Subsequently, H* migrates to Ru surface, where hydrogen recombination occurs to produce H2. This work paves a new avenue for the construction of coupled catalysts at the atomic scale to facilitate HER electrocatalysis.

Subnanometric Pt-W Bimetallic Clusters for Efficient Alkaline Hydrogen Evolution Electrocatalysis

Rational design and synthesis of subnanometric bimetallic clusters (SBCs) within a narrow size distribution, along with achieving full SBCs exposure on supporting materials, are formidable challenges that must be overcome to realize potential applications. This work details a facile strategy to synthesize fully exposed PtW SBCs with an average size of 0.81 nm on the surface of spherical N-doped carbon (PtW/NC), which is underpinned by the electrostatic interactions between the negatively charged [H3PtW6O24]5- polyanions and the positively charged closed-pore metal-organic framework (MOF) [Zn5(OH)2(AmTRZ)6]2+. The PtW/NC exhibits significant electrocatalytic performance and stability for the alkaline hydrogen evolution reaction with an ultralow overpotential of 4 mV at 10 mA cm-2, a low Tafel slope of 29 mV dec-1, and a long-term electrolysis stability exceeding 140 h. The Pt mass activity of PtW/NC is 34 times higher than that of commercial 20 wt % Pt/C at the 100 mV overpotential. Both theoretical calculations and electrochemical measurements indicate that a synergistic effect between Pt and W is responsible for this notable catalytic performance. The synthetic approach outlined in this work can be applied to other MOFs and coordination networks that lack pores or have limited porosity.

Low-valence platinum single atoms in sulfur-containing covalent organic frameworks for photocatalytic hydrogen evolution

This study focuses on optimizing catalytic activity in photocatalytic hydrogen evolution reaction by precisely designing and modulating the electronic structure of metal single atoms. The catalyst, denoted as PtSA@S-TFPT, integrates low-valence platinum single atoms into sulfur-containing covalent organic frameworks. The robust asymmetric four-coordination between sulfur and platinum within the framework enables a high platinum loading of 12.1 wt%, resulting in efficient photocatalytic hydrogen production activity of 11.4 mmol g-1 h-1 and stable performance under visible light. These outcomes are attributed to a reduced hydrogen desorption barrier and enhanced photogenerated charge separation, as indicated by density functional theory calculations and dynamic carrier analysis. This work challenges traditional notions and opens an avenue for developing low-valence metal single atom-loaded covalent organic framework catalysts to advance photocatalytic hydrogen evolution.

Lattice-Confined Single-Atom Catalyst: Preparation, Application and Electron Regulation Mechanism

Lattice-confined single-atom catalyst (LC SAC), featuring exceptional activity, intriguing stability and prominent selectivity, has attracted extensive attention in the fields of various reactions (e.g., hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), etc.). To design a "smart" LC SAC for catalytic applications, one must systematically comprehend updated advances in the preparation, the application, and especially the peculiar electron regulation mechanism of LC SAC. In this review, the specific preparation methods of LC SAC based on general coordination strategy are updated, and its applications in HER, OER, ORR, N2 reduction reaction (NRR), advanced oxidation processes (AOPs) and so forth are summarized to display outstanding activity, stability and selectivity. Uniquely, the electron regulation mechanisms are first and deeply discussed and can be primarily categorized as electron transfer bridge with monometallic active sites, novel catalytic centers with polymetallic active sites, and positive influence by surrounding environments. In the end, the existing issues and future development directions are put forward with a view to further optimize the performance of LC SAC. This review is expected to contribute to the in-depth understanding and practical application of highly efficient LC SAC.

Hexa-atom Pt Catalyst Fabricated by a Ligand Engineering Strategy for Efficient Hydrogen Oxidation Reaction

Atomically precise supported nanocluster catalysts (APSNCs), which feature exact atomic composition, well-defined structures, and unique catalytic properties, offer an exceptional platform for understanding the structure-performance relationship at the atomic level. However, fabricating APSNCs with precisely controlled and uniform metal atom numbers, as well as maintaining a stable structure, remains a significant challenge due to uncontrollable dispersion and easy aggregation during synthetic and catalytic processes. Herein, we developed an effective ligand engineering strategy to construct a Pt6 nanocluster catalyst stabilized on oxidized carbon nanotubes (Pt6/OCNT). The structural analysis revealed that Pt6 nanoclusters in Pt6/OCNT were fully exposed and exhibited a planar structure. Furthermore, the obtained Pt6/OCNT exhibited outstanding acidic HOR performances with a high mass activity of 18.37 A ⋅ mgpt -1 along with excellent stability during a 24 h constant operation and good CO tolerance, surpassing those of the commercial Pt/C. Density functional theory (DFT) calculations demonstrated that the unique geometric and electronic structures of Pt6 nanoclusters on OCNT altered the hydrogen adsorption energies on catalytic sites and thus lowered the HOR theoretical overpotential. This work presents a new prospect for designing and synthesizing advanced APSNCs for efficient energy electrocatalysis.

Single-Atom Underpotential Deposition at Specific Sites of N-Doped Graphene for Hydrogen Evolution Reaction Electrocatalysis

Single-atom catalysts (SACs) have the advantages of good active site uniformity, high atom utilization, and high catalytic activity. However, the study of its controllable synthesis still needs to be thoroughly investigated. In this paper, we deposited Cu SAs on nanoporous N-doped graphene by underpotential deposition and further obtained a Pt SAC by a galvanic process. Electrochemical and spectroscopic analyses showed that the pyridine-like N defect sites are the specific sites for the underpotential-deposited SAs. The obtained Pt SAC exhibits a good activity in a hydrogen evolution reaction with a turnover frequency of 25.1 s-1. This work reveals the specific sites of UPD of SAs on N-doped graphene and their potential applications in HERs, which provides a new idea for the design and synthesis of SACs.

Mechanistic insight into the synergy between platinum cluster and indium particle dual cocatalysts for enhanced photocatalytic water splitting

Photocatalytic H2 production is envisioned as a promising pillar of sustainable energy conversion system to address the energy crisis and environmental issues but still challenging. Herein, a strategy is proposed to design a dual-metal cocatalysts consisting of Pt nanoclusters (Pt NCs) and In nanoparticles (In NPs) anchored on polymeric carbon nitride (Pt-In/CN) for boosting photocatalytic water splitting. As expected, the designed Pt-In/CN photocatalyst exhibits an impressive H2 production rate of 6.49 mmol·h-1·g-1 with an apparent quantum yield (AQY) of 33.56 % at 400 nm, which is 2.8- and 11.2-fold higher than those of the Pt/CN and In/CN, respectively. Combining experimental characterization with theoretical calculation demonstrates the synergistic mechanisms underpinning the enhanced photocatalytic activity. The Pt NCs and In NPs serve as photogenerated electron and hole trapping sites, respectively, which achieves the spatial separation of charge carriers and induces the polarized surface charge distribution, thus fostering optimal adsorption behavior of intermediates. More importantly, the p-block In NPs modulate the electronic microenvironment of Pt NCs to attenuate the adsorption behavior of H* intermediates for accelerated H2 evolution kinetics. This work unveils a versatile strategy to regulate the electronic structures of dual-metal sites with synergy by establishing charge transfer mechanism for dual-metal cocatalysts.

Bacteriophage-like Nanobiocatalysts with Spiky Topography and Dual-Atom Sites for Treating Drug-Resistant Bacteria

Overuse of antibiotics leads to the proliferation of drug-resistant bacterial strains, worsening global morbidity, and mortality rates. Bioinspired nanomaterials present a promising avenue for developing nonantibiotic strategies against drug-resistant bacteria. Here, we engineer a bacteriophage-inspired artificial nanobiocatalyst via nonstoichiometric W18O49 that features a spiky topography and synergistic dual-atom sites for combating drug-resistant bacterial infection. Benefiting from the strong interaction within the synergistic Fe-O-Mo sites, the synthesized spiky artificial nanobiocatalyst exhibits superior reactive oxygen species (ROS)-catalytic activity, attributed to the regulated adsorption affinity between the reaction intermediates and catalytic sites. The experimental and theoretical investigations demonstrate that the bioinspired biocatalyst can effectively capture and kill bacteria through its spiky morphology and potent ROS-catalytic activity, which can enable a significant reduction in bacterial viability through downregulating genes associated with biosynthesis, cellular maintenance, and respiration. In vivo experiments demonstrate that the spiky artificial biocatalyst accelerates the reconstruction of drug-resistant bacteria-infected skin wounds in rabbits, exhibiting efficacy comparable to that of vancomycin. It is expected that this bioinspired study on spiky artificial nanobiocatalysts offers a straightforward path to facilitate the development of both bionic and nonantibiotic disinfection strategies.

Interfacial Ir-V Direct Metal Bonding Enhanced Hydrogen Evolution Activity in Vanadium Oxides Supported Catalysts

Tuning the interfacial structure of metal oxide substrates is an essential strategy to induce electronic structure reconstruction of supported catalysts, which is of great importance in optimizing their catalytic activities. Herein, vanadium oxides-supported Ir catalysts (Ir-V2O3, Ir-VO2, and Ir-V2O5) with different interfacial bonding environments (Ir-V, Ir-Obri, and Ir-O, respectively) were investigated for hydrogen evolution reaction (HER). The regulating mechanism of the influence of different interfacial bonding environments on HER activity was investigated by both experimental results and computational evidence. Benefiting from the unique advantages of interfacial Ir-V direct metal bonds in Ir-V2O3, including enhanced electron transfer and electron donation ability, an optimized HER performance can be obtained with lowest overpotentials of 16 and 26 mV at 10 mA cm-2, high mass activities of 11.24 and 6.66 A mg-1, and turnover frequency values of 11.20 and 6.63 s-1, in acidic and alkaline conditions respectively. Furthermore, the assembled Ir-V2O3||RuO2 anion exchange membrane (AEM) electrolyzer requires only 1.92 V to achieve a high current density of 500 mA cm-2 and realizes long-term stability. This study provides essential insights into the regulating mechanism of interfacial chemical bonding in electrocatalysts and offers a new pathway to design noble metal catalysts for different applications.

Phase-Transition of Mo2C Induced by Tungsten Doping as Heterointerface-Rich Electrocatalyst for Optimizing Hydrogen Evolution Activity

Electrochemical hydrogen evolution reaction (HER) from water splitting driven by renewable energy is considered a promising method for large-scale hydrogen production, and as an alternative to noble-metal electrocatalysts, molybdenum carbide (Mo2C) has exhibited effective HER performance. However, the strong bonding strength of intermediate adsorbed H (Hads) with Mo active site slows down the HER kinetics of Mo2C. Herein, using phase-transition strategy, hexagonal β-Mo2C could be easily transferred to cubic δ-Mo2C through electron injection triggered by tungsten (W) doping, and heterointerface-rich Mo2C-based composites, including β-Mo2C, δ-Mo2C, and MoO2, are presented. Experimental results and density functional theory calculations reveal that W doping mainly contributes to the phase-transition process, and the generated heterointerfaces are the dominant factor in inducing remarkable electron accumulation around Mo active sites, thus weakening the Mo─H coupling. Wherein, the β-Mo2C/MoO2 interface plays an important role in optimizing the electronic structure of Mo 3d orbital and hydrogen adsorption Gibbs free energy (ΔGH*), enabling these Mo2C-based composites to have excellent intrinsic catalytic activity like low overpotential (η10 = 99.8 mV), small Tafel slope (60.16 dec-1), and good stability in 1 m KOH. This work sheds light on phase-transition engineering and offers a convenient route to construct heterointerfaces for large-scale HER production.

Alveoli-Inspired Carbon Cathodes with Interconnected Porous Structure and Asymmetric Coordinated Vanadium Sites for Superior Li-S Batteries

Accelerating sulfur conversion catalysis to alleviate the shuttle effect has become a novel paradigm for effective Li-S batteries. Although nitrogen-coordinated metal single-atom (M-N4) catalysts have been investigated, further optimizing its utilization rate and catalytic activities is urgently needed for practical applications. Inspired by the natural alveoli tissue with interconnected structure and well-distributed enzyme catalytic sites on the wall for the simultaneously fast diffusion and in situ catalytic conversion of substrates, here, we proposed the controllable synthesis of bioinspired carbon cathode with interconnected porous structure and asymmetric coordinated V-S1N3 sites for efficient and stable Li-S batteries. The enzyme-mimetic V-S1N3 shows asymmetric electronic distribution and high tunability, therefore enhancing in situ polysulfide conversion activities. Experimental and theoretical results reveal that the high charge asymmetry degree and large atom radius of S in V-S1N3 result in sloping adsorption for polysulfide, thereby exhibiting low thermodynamic energy barriers and long-range stability (0.076 % decay over 600 cycles).

Rational Design of Dynamic Interface Water Evolution on Turing Electrocatalyst toward the Industrial Hydrogen Production

Manipulating the structural and kinetic dissociation processes of water at the catalyst-electrolyte interface is vital for alkaline hydrogen evolution reactions (HER) at industrial current density. This is seldom actualized due to the intricacies of the electrochemical reaction interface. Herein, this work introduces a rapid, nonequilibrium cooling technique for synthesizing ternary Turing catalysts with short-range ordered structures (denoted as FeNiRu/C). These advanced structures empower the FeNiRu/C to exhibit excellent HER performance in 1 m KOH with an ultralow overpotential of 6.5 and 166.2 mV at 10 and 1000 mA cm-2, respectively, and a specific activity 7.3 times higher than that of Pt/C. Comprehensive mechanistic analyses reveal that abundant atomic species form asymmetric atomic electric fields on the catalyst surface inducing a directed evolution and the dissociation process of interfacial H2O molecules. In addition, the locally topologized structure effectively mitigates the high hydrogen coverage of the active site induced by the high current density. The establishment of the relationship between free water population and HER activity provides a new paradigm for the design of industrially relevant high performance alkaline HER catalysts.

Crystalline nanosheets of three-dimensional supramolecular frameworks with uniform thickness and high stability

Fabricating three dimensional (3D) supramolecular frameworks (SMFs) into stable crystalline nanosheets remains a great challenge due to the homogeneous and weak inter-building block interactions along 3D directions. Herein, crystalline nanosheets of a 3D SMF with a uniform thickness of 4.8 ± 0.1 nm immobilized with Pt nanocrystals on the surface (Q[8]/Pt NSs) were fabricated via the solid-liquid reaction between cucurbit[8]uril/H2PtCl6 single crystals and hydrazine hydrate with the help of gas and heat yielded during the reaction process. A series of experiments and theoretical calculations reveal the ultrahigh stability of Q[8]/Pt NSs due to the high density hydrogen bonding interaction among neighboring Q[8] molecules. This in turn endows Q[8]/Pt NSs with excellent photocatalytic and continuous thermocatalytic CO oxidation performance, representing the thus-far reported best Pt nano-material-based catalysts.

The impact of support electronegativity on the electrochemical properties of platinum

Modulating the electronic structure of platinum (Pt) through a support is an important strategy for enhancing its electrocatalytic properties. In this work, to explore the impact of support electronegativity on Pt's catalytic activity for hydrogen evolution, we chose diverse metals with varying electronegativities that are stable in acidic solutions, such as titanium (Ti), molybdenum (Mo), and tungsten (W), as supports. Ti is the optimal support according to density functional theory (DFT) calculations. As expected, the Pt@Ti catalyst demonstrated remarkable efficiency in the hydrogen evolution reaction (HER), displaying a minimal overpotential of 13 mV at -10 mA cm-2, a Tafel slope of 34.5 mV dec-1, and sustained durability over 110 h in a 0.5 M H2SO4 solution. To unravel the metal-support interaction (MSI) between Pt and Ti, a comprehensive exploration encompassing both experimental investigations and DFT calculations was undertaken. The results elucidate that the outstanding HER performance of Pt@Ti stems from robust synergies forged between Pt and Ti atoms within the Ti support. This work not only furnishes a technique for producing electrocatalysts with superior efficiency and stability but also streamlines the process of choosing the most appropriate metal support. Moreover, it enhances comprehension of the interaction between Pt and the metal support.

Directed Dual Charge Pumping Tunes the d-Orbital Configuration of Pt Cluster Boosting Hydrogen Evolution Kinetic

Achieving high catalytic activity with a minimum amount of platinum (Pt) is crucial for accelerating the cathodic hydrogen evolution reaction (HER) in proton exchange membrane (PEM) water electrolysis, yet it remains a significant challenge. Herein, a directed dual-charge pumping strategy to tune the d-orbital electronic distribution of Pt nanoclusters for efficient HER catalysis is proposed. Theoretical analysis reveals that the ligand effect and electronic metal-support interactions (EMSI) create an effective directional electron transfer channel for the d-orbital electrons of Pt, which in turn optimizes the binding strength to H*, thereby significantly enhancing HER efficiency of the Pt site. Experimentally, this directed dual-charge pumping strategy is validated by elaborating Sb-doped SnO2 (ATO) supported Fe-doped PtSn heterostructure catalysts (Fe-PtSn/ATO). The synthesized 3%Fe-PtSn/ATO catalysts exhibit lower overpotential (requiring only 10.5 mV to reach a current density of 10 mA cm- 2), higher mass activity (28.6 times higher than commercial 20 wt.% Pt/C), and stability in the HER process in acidic media. This innovative strategy presents a promising pathway for the development of highly efficient HER catalysts with low Pt loading.

Regulating Hydrogen/Oxygen Species Adsorption via Built-in Electric Field -Driven Electron Transfer Behavior at the Heterointerface for Efficient Water Splitting

Alkaline water electrolysis (AWE) plays a crucial role in the realization of a hydrogen economy. The design and development of efficient and stable bifunctional catalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are pivotal to achieving high-efficiency AWE. Herein, WC1-x/Mo2C nanoparticle-embedded carbon nanofiber (WC1-x/Mo2C@CNF) with abundant interfaces is successfully designed and synthesized. Benefiting from the electron transfer behavior from Mo2C to WC1-x, the electrocatalysts of WC1-x/Mo2C@CNF exhibit superior HER and OER performance. Furthermore, when employed as anode and cathode in membrane electrode assembly devices, the WC1-x/Mo2C@CNF catalyst exhibits enhanced catalytic activity and remarkable stability for 100 hours at a high current density of 200 mA cm-2 towards overall water splitting. The experimental characterizations and theoretical simulation reveal that modulation of the d-band center for WC1-x/Mo2C@CNF, achieved through the asymmetric charge distribution resulting from the built-in electric field induced by work function, enables optimization of adsorption strength for hydrogen/oxygen intermediates, thereby promoting the catalytic kinetics for overall water splitting. This work provides promising strategies for designing highly active catalysts in energy conversion fields.

Polyoxometalate-Structured Materials: Molecular Fundamentals and Electrocatalytic Roles in Energy Conversion

Polyoxometalates (POMs), a kind of molecular metal oxide cluster with unique physical-chemical properties, have made essential contributions to creating efficient and robust electrocatalysts in renewable energy systems. Due to the fundamental advantages of POMs, such as the diversity of molecular structures and large numbers of redox active sites, numerous efforts have been devoted to extending their application areas. Up to now, various strategies of assembling POM molecules into superstructures, supporting POMs on heterogeneous substrates, and POMs-derived metal compounds have been developed for synthesizing electrocatalysts. From a multidisciplinary perspective, the latest advances in creating POM-structured materials with a unique focus on their molecular fundamentals, electrocatalytic roles, and the recent breakthroughs of POMs and POM-derived electrocatalysts, are systematically summarized. Notably, this paper focuses on exposing the current states, essences, and mechanisms of how POM-structured materials influence their electrocatalytic activities and discloses the critical requirements for future developments. The future challenges, objectives, comparisons, and perspectives for creating POM-structured materials are also systematically discussed. It is anticipated that this review will offer a substantial impact on stimulating interdisciplinary efforts for the prosperities and widespread utilizations of POM-structured materials in electrocatalysis.

Nitrided Rhodium Nanoclusters with Optimized Water Bonding and Splitting Effects for pH-Universal H2-Production

The nitridation of noble metals-based catalysts to further enhance their hydrogen evolution reaction (HER) kinetics in neutral and alkaline conditions would be an effective strategy for developing high-performance wide pH HER catalysts. Herein, a facile molten urea method is employed to construct the nitrided Rh nanoclusters (RhxN) supported on N-doped carbon (RhxN-NC). The uniformly distributed RhxN clusters exhibited optimized water bonding and splitting effects, therefore resulting in excellent pH-universal HER performance. The optimized RhxN-NC catalyst only requires 8, 12, and 109 mV overpotentials to reach the current density of 10 mA cm-2 in 0.5 M H2SO4, 1.0 M KOH, and 1.0 M PBS electrolytes, respectively. The spectroscopic characterizations and theoretical calculation further confirm the vital role of Rh-N moieties in RhxN clusters in improving the transfer of electrons and facilitating the generation of H2. This work not only provides a suitable nitridation method for noble metal species in mild conditions but also makes a breakthrough in synthesizing noble metal nitrides-based electrocatalysts to achieve an exceptional wide-pH HER performance and other catalysis.

Rapid carbothermal shocking fabrication of iron-incorporated molybdenum oxide with heterogeneous spin states for enhanced overall water/seawater splitting

Molybdenum dioxide (MoO2) has been considered as a promising hydrogen evolution reaction (HER) electrocatalyst. However, the active sites are mainly located at the edges, resulting in few active sites and poor activity in the HER. Herein, we first reported on an efficient strategy to incorporate Fe into MoO2 nanosheets on Ni foam (Fe-MoO2/NF) using a rapid carbothermal shocking method (820 °C for 127 s). Notably, the different spin states between Fe and Mo atoms could lead to rich lattice dislocations in Fe-MoO2/NF, exposing abundant oxygen vacancies and the low-oxidation-state of Mo sites during the rapid Joule heating process. As tested, the catalyst exhibited superior activity with ultralow overpotentials (HER: 17 mV@10 mA cm-2; oxygen evolution reaction (OER): 310 mV@50 mA cm-2) and high OER selectivity in alkaline seawater splitting. Meanwhile, this catalyst was equipped in a home-made anion exchange membrane (AEM) seawater electrolyzer, which achieved a low energy consumption (5.5 kW h m-3). More importantly, Fe-MoO2/NF also coupled very well with a solar-driven electrolytic system and turned out a solar-to-hydrogen (STH) efficiency of 13.5%. Theoretical results also demonstrated that Fe incorporated and abundant oxygen vacancies in MoO2 can distort the distance of the Mo-O bonds and regulate the electronic structure, thus optimizing the binding energy of H*/OOH* adsorption. This method can be extended to other heterogeneous spin states in MoO2-based catalysts (e.g. Ni-MoO2/NF, Co-MoO2/NF) for seawater splitting, and provide a simple, efficient and universal strategy to prepare highly-efficient MoO2-based electrocatalysts.

Alleviating OH Blockage on the Catalyst Surface by the Puncture Effect of Single-Atom Sites to Boost Alkaline Water Electrolysis

Nonprecious transition metal catalysts have emerged as the preferred choice for industrial alkaline water electrolysis due to their cost-effectiveness. However, their overstrong binding energy to adsorbed OH often results in the blockage of active sites, particularly in the cathodic hydrogen evolution reaction. Herein, we found that single-atom sites exhibit a puncture effect to effectively alleviate OH blockades, thereby significantly enhancing the alkaline hydrogen evolution reaction (HER) performance. Typically, after anchoring single Ru atoms onto tungsten carbides, the overpotential at 10 mA·cm-2 is reduced by more than 130 mV (159 vs 21 mV). Also, the mass activity is increased 16-fold over commercial Pt/C (MA100 = 17.3 A·mgRu-1 vs 1.1 A·mgPt-1, Pt/C). More importantly, such electrocatalyst-based alkaline anion-exchange membrane water electrolyzers can exhibit an ultralow potential (1.79 Vcell) and high stability at an industrial current density of 1.0 A·cm-2. Density functional theory (DFT) calculations reveal that the isolated Ru sites could weaken the surrounding local OH binding energy, thus puncturing OH blockage and constructing bifunctional interfaces between Ru atoms and the support to accelerate water dissociation. Our findings exhibit generality to other transition metal catalysts (such as Mo) and contribute to the advancement of industrial-scale alkaline water electrolysis.

Facilitating alkaline hydrogen evolution reaction on the hetero-interfaced Ru/RuO2 through Pt single atoms doping

Exploring an active and cost-effective electrocatalyst alternative to carbon-supported platinum nanoparticles for alkaline hydrogen evolution reaction (HER) have remained elusive to date. Here, we report a catalyst based on platinum single atoms (SAs) doped into the hetero-interfaced Ru/RuO2 support (referred to as Pt-Ru/RuO2), which features a low HER overpotential, an excellent stability and a distinctly enhanced cost-based activity compared to commercial Pt/C and Ru/C in 1 M KOH. Advanced physico-chemical characterizations disclose that the sluggish water dissociation is accelerated by RuO2 while Pt SAs and the metallic Ru facilitate the subsequent H* combination. Theoretical calculations correlate with the experimental findings. Furthermore, Pt-Ru/RuO2 only requires 1.90 V to reach 1 A cm-2 and delivers a high price activity in the anion exchange membrane water electrolyzer, outperforming the benchmark Pt/C. This research offers a feasible guidance for developing the noble metal-based catalysts with high performance and low cost toward practical H2 production.

Manipulating the Microenvironment of Single Atoms by Switching Support Crystallinity for Industrial Hydrogen Evolution

Modulating the microenvironment of single-atom catalysts (SACs) is critical to optimizing catalytic activity. Herein, we innovatively propose a strategy to improve the local reaction environment of Ru single atoms by precisely switching the crystallinity of the support from high crystalline and low crystalline, which significantly improves the hydrogen evolution reaction (HER) activity. The Ru single-atom catalyst anchored on low-crystalline nickel hydroxide (Ru-LC-Ni(OH)2 ) reconstructs the distribution balance of the interfacial ions due to the activation effect of metal dangling bonds on the support. Single-site Ru with a low oxidation state induces the aggregation of hydronium ions (H3 O+ ), leading to the formation of a local acidic microenvironment in alkaline media, breaking the pH-dependent HER activity. As a comparison, the Ru single-atom catalyst anchored on high-crystalline nickel hydroxide (Ru-HC-Ni(OH)2 ) exhibits a sluggish Volmer step and a conventional local reaction environment. As expected, Ru-LC-Ni(OH)2 requires low overpotentials of 9 and 136 mV at 10 and 1000 mA cm-2 in alkaline conditions and operates stably at 500 mA cm-2 for 500 h in an alkaline seawater anion exchange membrane (AEM) electrolyzer. This study provides a new perspective for constructing highly active single-atom electrocatalysts.

A Highly-Efficient Boron Interstitially Inserted Ru Anode Catalyst for Anion Exchange Membrane Fuel Cells

Developing high-performance electrocatalysts for alkaline hydrogen oxidation reaction (HOR) is crucial for the commercialization of anion exchange membrane fuel cells (AEMFCs). Here, boron interstitially inserted ruthenium (B-Ru/C) is synthesized and used as an anode catalyst for AEMFC, achieving a peak power density of 1.37 W cm-2 , close to the state-of-the-art commercial PtRu catalyst. Unexpectedly, instead of the monotonous decline of HOR kinetics with pH as generally believed, an inflection point behavior in the pH-dependent HOR kinetics on B-Ru/C is observed, showing an anomalous behavior that the HOR activity under alkaline electrolyte surpasses acidic electrolyte. Experimental results and density functional theory calculations reveal that the upshifted d-band center of Ru after the intervention of interstitial boron can lead to enhanced adsorption ability of OH and H2 O, which together with the reduced energy barrier of water formation, contributes to the outstanding alkaline HOR performance with a mass activity of 1.716 mA µgPGM -1 , which is 13.4-fold and 5.2-fold higher than that of Ru/C and commercial Pt/C, respectively.

Recent insights on the use of modified Zn-based catalysts in eCO2RR

Converting CO2 into valuable chemicals can provide a new path to mitigate the greenhouse effect, achieving the aim of "carbon neutrality" and "carbon peaking". Among numerous electrocatalysts, Zn-based materials are widely distributed and cheap, making them one of the most promising electrocatalyst materials to replace noble metal catalysts. Moreover, the Zn metal itself has a certain selectivity for CO. After appropriate modification, such as oxide derivatization, structural reorganization, reconstruction of the surfaces, heteroatom doping, and so on, the Zn-based electrocatalysts can expose more active sites and adjust the d-band center or electronic structure, and the FE and stability of them can be effectively improved, and they can even convert CO2 to multi-carbon products. This review aims to systematically describe the latest progresses of modified Zn-based electrocatalyst materials (including organic and inorganic materials) in the electrocatalytic carbon dioxide reduction reaction (eCO2RR). The applications of modified Zn-based catalysts in improving product selectivity, increasing current density and reducing the overpotential of the eCO2RR are reviewed. Moreover, this review describes the reasonable selection and good structural design of Zn-based catalysts, presents the characteristics of various modified zinc-based catalysts, and reveals the related catalytic mechanisms for the first time. Finally, the current status and development prospects of modified Zn-based catalysts in eCO2RR are summarized and discussed.

Current Progress of Mo-Based Metal Organic Frameworks Derived Electrocatalysts for Hydrogen Evolution Reaction

As an important half-reaction for electrochemical water splitting, electrocatalytic hydrogen evolution reaction suffers from sluggish kinetics, and it is still urgent to search high efficiency non-platinum-based electrocatalysts. Mo-based catalysts such as Mo2 C, MoO2 , MoP, MoS2 , and MoNx have emerged as promising alternatives to Pt/C owing to their similar electronic structure with Pt and abundant reserve of Mo. On the other hand, due to the adjustable topology, porosity, and nanostructure of metal organic frameworks (MOFs), MOFs are extensively used as precursors to prepare nano-electrocatalysts. In this review, for the first time, the progress of Mo-MOFs-derived electrocatalysts for hydrogen evolution reaction is summarized. The preparation method, structures, and catalytic performance of the catalysts are illustrated based on the types of the derived electrocatalysts including Mo2 C, MoO2 , MoP, MoS2 , and MoNx . Especially, the commonly used strategies to improve catalytic performance such as heteroatoms doping, constructing heterogeneous structure, and composited with noble metal are discussed. Moreover, the opportunities and challenges in this area are proposed to guide the designment and development of Mo-based MOF derived electrocatalysts.

Construction of Ni2P-MoC/Coal-Based Carbon Fiber Self-Supporting Catalysts for Enhanced Hydrogen Evolution

Efficient and inexpensive electrocatalysts play an important role in the hydrogen evolution reaction (HER) of electrolytic water splitting. Herein, Ni2P-MoC/coal-based carbon fiber (Ni2P-MoC/C-CF) self-supporting catalysts were obtained by low-temperature phosphorization and high-temperature carbonization. The Mo source and oxidized coal were uniformly dispersed in the carbon support by electrospinning technology. A precursor of Ni was introduced by the impregnation method. The synergistic effect of MoC and Ni2P may reduce the strong hydrogen adsorption capacity of pure MoC and provide a fast hydrogen release process. In addition, the C-CFs prepared by electrospinning can not only prevent the agglomeration of MoC and Ni2P particles at a high temperature but also provide a self-supporting support for the catalyst. As a result, the catalytic performance of the HER was improved greatly, and a low overpotential of 112 mV at 10 mA cm-2 was exhibited stably by the Ni2P-MoC/C-CFs. This work not only converts coal into coal-based carbon materials but also provides a feasible pathway for the rational design of large-scale molded hydrogen electrocatalysts.

Green electrosynthesis of 3,3'-diamino-4,4'-azofurazan energetic materials coupled with energy-efficient hydrogen production over Pt-based catalysts

The broad employment of clean hydrogen through water electrolysis is restricted by large voltage requirement and energy consumption because of the sluggish anodic oxygen evolution reaction. Here we demonstrate a novel alternative oxidation reaction of green electrosynthesis of valuable 3,3'-diamino-4,4'-azofurazan energetic materials and coupled with hydrogen production. Such a strategy could greatly decrease the hazard from the traditional synthetic condition of 3,3'-diamino-4,4'-azofurazan and achieve low-cell-voltage hydrogen production on WS2/Pt single-atom/nanoparticle catalyst. The assembled two-electrode electrolyzer could reach 10 and 100 mA cm-2 with ultralow cell voltages of 1.26 and 1.55 V and electricity consumption of only 3.01 and 3.70 kWh per m3 of H2 in contrast of the conventional water electrolysis (~5 kWh per m3). Density functional theory calculations combine with experimental design decipher the synergistic effect in WS2/Pt for promoting Volmer-Tafel kinetic rate during alkaline hydrogen evolution reaction, while the oxidative-coupling of starting materials driven by free radical could be the underlying mechanism during the synthesis of 3,3'-diamino-4,4'-azofurazan. This work provides a promising avenue for the concurrent electrosynthesis of energetic materials and low-energy-consumption hydrogen production.

Metal Alloys-Structured Electrocatalysts: Metal-Metal Interactions, Coordination Microenvironments, and Structural Property-Reactivity Relationships

Metal alloys-structured electrocatalysts (MAECs) have made essential contributions to accelerating the practical applications of electrocatalytic devices in renewable energy systems. However, due to the complex atomic structures, varied electronic states, and abundant supports, precisely decoding the metal-metal interactions and structure-activity relationships of MAECs still confronts great challenges, which is critical to direct the future engineering and optimization of MAECs. Here, this timely review comprehensively summarizes the latest advances in creating the MAECs, including the metal-metal interactions, coordination microenvironments, and structure-activity relationships. First, the fundamental classification, design, characterization, and structural reconstruction of MAECs are outlined. Then, the electrocatalytic merits and modulation strategies of recent breakthroughs for noble and non-noble metal-structured MAECs are thoroughly discussed, such as solid solution alloys, intermetallic alloys, and single-atom alloys. Particularly, unique insights into the bond interactions, theoretical understanding, and operando techniques for mechanism disclosure are given. Thereafter, the current states of diverse MAECs with a unique focus on structural property-reactivity relationships, reaction pathways, and performance comparisons are discussed. Finally, the future challenges and perspectives for MAECs are systematically discussed. It is believed that this comprehensive review can offer a substantial impact on stimulating the widespread utilization of metal alloys-structured materials in electrocatalysis.

Avoiding Sabatier's Limitation on Spatially Correlated Pt-Mn Atomic Pair Sites for Oxygen Electroreduction

The development of highly active and low-cost oxygen reduction reaction (ORR) catalysts is crucial for the practical application of hydrogen fuel cells. However, the linear scaling relation (LSR) imposes an inherent Sabatier's limitation for most catalysts including the benchmark Pt with an insurmountable overpotential ceiling, impeding the development of efficient electrocatalysts. To avoid such a limitation, using earth-abundant metal oxides with different crystal phases as model materials, we propose an effective and dynamic reaction pathway through constructing spatially correlated Pt-Mn pair sites, achieving an excellent balance between high activity and low Pt loading. Experimental and theoretical calculations demonstrate that manipulating the intermetallic distance and charge distribution of Pt-Mn pairs can effectively promote O-O bond cleavage at these sites through a bridge configuration, circumventing the formation of *OOH intermediates. Meanwhile, the dynamic adsorption configuration transition from the bridge configuration of O2 to the end-on configuration of *OH improves *OH desorption at the Mn site within such pairs, thereby avoiding Sabatier's limitation. The well-designed Pt-Mn/β-MnO2 exhibits outstanding ORR activity and stability with a half-wave potential of 0.93 V and barely any activity degradation for 70 h. When applied to the cathode of a H2-O2 anion-exchange membrane fuel cell, this catalyst demonstrates a high peak power density of 287 mW cm-2 and 500 h of stability under a cell voltage of 0.6 V. This work reveals the adaptive bonding interactions of atomic pair sites with multiple reactant/intermediates, offering a new avenue for rational design of highly efficient atomic-level dispersed ORR catalysts beyond the Sabatier optimum.

Tuning Binding Strength of Multiple Intermediates towards Efficient pH-universal Electrocatalytic Hydrogen Evolution by Mo8 O26 -NbNx Oy Heterocatalysts

Developing efficient and robust hydrogen evolution reaction (HER) catalysts for scalable and sustainable hydrogen production through electrochemical water splitting is strategic and challenging. Herein, heterogeneous Mo8 O26 -NbNx Oy supported on N-doped graphene (defined as Mo8 O26 -NbNx Oy /NG) is synthesized by controllable hydrothermal reaction and nitridation process. The O-exposed Mo8 O26 clusters covalently confined on NbNx Oy nanodomains provide a distinctive interface configuration and appropriate electronic structure, where fully exposed multiple active sites give excellent HER performance beyond commercial Pt/C catalyst in pH-universal electrolytes. Theoretical studies reveal that the Mo8 O26 -NbNx Oy interface with electronic reconstruction affords near-optimal hydrogen adsorption energy and enhanced initial H2 O adsorption. Furthermore, the terminal O atoms in Mo8 O26 clusters cooperate with Nb atoms to promote the initial H2 O adsorption, and subsequently reduce the H2 O dissociation energy, accelerating the entire HER kinetics.

Realistic Modeling of the Electrocatalytic Process at Complex Solid-Liquid Interface

The rational design of electrocatalysis has emerged as one of the most thriving means for mitigating energy and environmental crises. The key to this effort is the understanding of the complex electrochemical interface, wherein the electrode potential as well as various internal factors such as H-bond network, adsorbate coverage, and dynamic behavior of the interface collectively contribute to the electrocatalytic activity and selectivity. In this context, the authors have reviewed recent theoretical advances, and especially, the contributions to modeling the realistic electrocatalytic processes at complex electrochemical interfaces,  and illustrated the challenges and fundamental problems in this field. Specifically, the significance of the inclusion of explicit solvation and electrode potential as well as the strategies toward the design of highly efficient electrocatalysts are discussed. The structure-activity relationships and their dynamic responses to the environment and catalytic functionality under working conditions are illustrated to be crucial factors for understanding the complexed interface and the electrocatalytic activities. It is hoped that this review can help spark new research passion and ultimately bring a step closer to a realistic and systematic modeling method for electrocatalysis.

Switching the Oxygen Evolution Mechanism on Atomically Dispersed Ru for Enhanced Acidic Reaction Kinetics

Designing stable single-atom electrocatalysts with lower energy barriers is urgent for the acidic oxygen evolution reaction. In particular, the atomic catalysts are highly dependent on the kinetically sluggish acid-base mechanism, limiting the reaction paths of intermediates. Herein, we successfully manipulate the steric localization of Ru single atoms at the Co3O4 surface to improve acidic oxygen evolution by precise control of the anchor sites. The delicate structure design can switch the reaction mechanism from the lattice oxygen mechanism (LOM) to the optimized adsorbate evolution mechanism (AEM). In particular, Ru atoms embedded into cation vacancies reveal an optimized mechanism that activates the proton donor-acceptor function (PDAM), demonstrating a new single-atom catalytic pathway to circumvent the classic scaling relationship. Steric interactions with intermediates at the anchored Ru-O-Co interface played a primary role in optimizing the intermediates' conformation and reducing the energy barrier. As a comparison, Ru atoms confined to the surface sites exhibit a lattice oxygen mechanism for the oxygen evolution process. As a result, the delicate atom control of the spatial position presents a 100-fold increase in mass activity from 36.96 A gRu(ads)-1 to 4012.11 A gRu(anc)-1 at 1.50 V. These findings offer new insights into the precise control of single-atom catalytic behavior.

Stabilizing Low-Valence Single Atoms by Constructing Metalloid Tungsten Carbide Supports for Efficient Hydrogen Oxidation and Evolution

Designing novel single-atom catalysts (SACs) supports to modulate the electronic structure is crucial to optimize the catalytic activity, but rather challenging. Herein, a general strategy is proposed to utilize the metalloid properties of supports to trap and stabilize single-atoms with low-valence states. A series of single-atoms supported on the surface of tungsten carbide (M-WCx , M=Ru, Ir, Pd) are rationally developed through a facile pyrolysis method. Benefiting from the metalloid properties of WCx , the single-atoms exhibit weak coordination with surface W and C atoms, resulting in the formation of low-valence active centers similar to metals. The unique metal-metal interaction effectively stabilizes the low-valence single atoms on the WCx surface and improves the electronic orbital energy level distribution of the active sites. As expected, the representative Ru-WCx exhibits superior mass activities of 7.84 and 62.52 A mgRu -1 for the hydrogen oxidation and evolution reactions (HOR/HER), respectively. In-depth mechanistic analysis demonstrates that an ideal dual-sites cooperative mechanism achieves a suitable adsorption balance of Had and OHad , resulting in an energetically favorable Volmer step. This work offers new guidance for the precise construction of highly active SACs.

WCx-Supported RuNi Single Atoms for Electrocatalytic Oxygen Evolution

Single-atom catalysts anchored to oxide or carbonaceous substances are typically tightly coordinated by oxygen or heteroatoms, which certainly impact their electronic structure and coordination environment, thereby affecting their catalytic activity. In this study, we prepared a stable oxygen evolution reaction (OER) catalyst on tungsten carbide using a simple pyrolysis method. The unique structure of tungsten carbide allows the atomic RuNi catalytic site to weakly bond to the surface W and C atoms. XRD patterns and HRTEM images of the WCx-RuNi showed the characteristics of phase-pure WC and W2C, and the absence of nanoparticles. Combined with XPS, the atomic dispersion of Ru/Ni in the catalyst was confirmed. The catalyst exhibits excellent catalytic ability, with a low overpotential of 330 mV at 50 mA/cm2 in 1 m KOH solutions, and demonstrates high long-term stability. This high OER activity is ascribed to the synergistic action of metal Ru/Ni atoms with double monomers. The addition of Ni increases the state density of WCx-RuNi near the Fermi level, promoting the adsorption of oxygen-containing intermediates and enhancing electron exchange. The larger proximity of the d band center to the Fermi level suggests a strong interaction between the d electrons and the valence or conduction band, facilitating charge transfer. Our research offers a promising avenue for reasonable utilization of inexpensive and durable WCx carrier-supported metal single-atom catalysts for electrochemical catalysis.

Defect Engineering of a High-Entropy Metallic Glass Surface for High-Performance Overall Water Splitting at Ampere-Level Current Densities

Platinum-based electrocatalysts possess high water electrolysis activity and are essential components for hydrogen evolution reaction (HER). A major challenge, however, is how to break the cost-efficiency trade-off. Here, a novel defect engineering strategy is presented to construct a nanoporous (FeCoNiB0.75 )97 Pt3 (atomic %) high-entropy metallic glass (HEMG) with a nanocrystalline surface structure that contains large amounts of lattice distortion and stacking faults to achieve excellent electrocatalytic performance using only 3 at% of Pt. The defect-rich HEMG achieves ultralow overpotentials at ampere-level current density of 1000 mA cm-2 for HER (104 mV) and oxygen evolution reaction (301 mV) under alkaline conditions, while retains a long-term durability exceeding 200 h at 100 mA cm-2 . Moreover, it only requires 81 and 122 mV to drive the current densities of 1000 and 100 mA cm-2 for HER under acidic and neutral conditions, respectively. Modelling results reveal that lattice distortion and stacking fault defects help to optimize atomic configuration and modulate electronic interaction, while the surface nanoporous architecture provides abundant active sites, thus synergistically contributing to the reduced energy barrier for water electrolysis. This defect engineering approach combined with a HEMG design strategy is expected to be widely applicable for development of high-performance alloy catalysts.

Mn-Oxygen Compounds Coordinated Ruthenium Sites with Deprotonated and Low Oxophilic Microenvironments for Membrane Electrolyzer-Based H2 -Production

Among the platinum-group metals, ruthenium (Ru), with a low water dissociation energy, is considered a promising alternative to substitute Pt for catalyzing hydrogen evolution reaction (HER). However, optimizing the adsorption-desorption energies of H* and OH* intermediates on Ru catalytic sites is extremely desirable but remains challenging. Inspired by the natural catalytic characteristics of Mn-oxygen complex, this study reports to design Mn-oxygen compounds coordinated Ru sites (MOC-Ru) with deprotonated and low oxophilic microenvironments for modulating the adsorption-desorption of H* and OH* to promote HER kinetics. Benefiting from the unique advantages of MOC structures, including weakened HOH bond at interface, electron donation ability, and deprotonation capability, the MOC-Ru exhibits extremely low overpotential and ultralong stability in both acidic and alkaline electrolytes. Experimental observations and theoretical calculations elucidate that the MOC can accelerate water dissociation kinetics and promote OH* desorption in alkaline conditions and trigger the long-range H* spillover for H2 -release in acid conditions. The outstanding activity and stability of membrane electrolyzer display that the MOC-Ru catalyst holds great potential as cathode for H2 -production. This study provides essential insights into the crucial roles of deprotonated and low oxophilic microenvironments in HER catalysis and offers a new pathway to create an efficient water-splitting cathode.

Ru-W Pair Sites Enabling the Ensemble Catalysis for Efficient Hydrogen Evolution

Simultaneously optimizing elementary steps, such as water dissociation, hydroxyl transferring, and hydrogen combination, is crucial yet challenging for achieving efficient hydrogen evolution reaction (HER) in alkaline media. Herein, Ru single atom-doped WO2 nanoparticles with atomically dispersed Ru-W pair sites (Ru-W/WO2 -800) are developed using a crystalline lattice-confined strategy, aiming to gain efficient alkaline HER. It is found that Ru-W/WO2 -800 exhibits remarkable HER activity, characterized by a low overpotential (11 mV at 10 mA cm-2 ), notable mass activity (5863 mA mg-1 Ru at 50 mV), and robust stability (500 h at 250 mA cm-2 ). The highly efficient activity of Ru-W/WO2 -800 is attributed to the synergistic effect of Ru-W sites through ensemble catalysis. Specifically, the W sites expedite rapid hydroxyl transferring and water dissociation, while the Ru sites accelerate the hydrogen combination process, synergistically facilitating the HER activity. This study opens a promising pathway for tailoring the coordination environment of atomic-scale catalysts to achieve efficient electro-catalysis.

Modulating Water Splitting Kinetics via Charge Transfer and Interfacial Hydrogen Spillover Effect for Robust Hydrogen Evolution Catalysis in Alkaline Media

Designing and synthesizing advanced electrocatalysts with superior intrinsic activity toward hydrogen evolution reaction (HER) in alkaline media is critical for the hydrogen economy. Herein, a novel Ir@Rhene heterojunction electrocatalyst is synthesized via epitaxially confining ultrasmall and low-coordinate Ir nanoclusters on the ultrathin Rh metallene accompanying the formation of Ir/IrO2 Janus nanoparticles. The as-prepared heterojunctions display outstanding alkaline HER activity, with an overpotential of only 17 mV at 10 mA cm-2 and an ultralow Tafel slope of 14.7 mV dec-1 . Both structural characterizations and theoretical calculations demonstrate that the Ir@Rhene heterointerfaces induce charge density redistribution, resulting in the increment of the electron density around the O atoms in the IrO2 site and thus delivering much lower water dissociation energy. In addition, the dual-site synergetic effects between IrO2 and Ir/Rh interface trigger and improve the interfacial hydrogen spillover, thereby subtly avoiding the steric blocking of the active site and eventually accelerating the alkaline HER kinetics.

Electronic Structure Engineering of Pt Species over Pt/WO3 toward Highly Efficient Electrocatalytic Hydrogen Evolution

Pt-based supported materials, a widely used electrocatalyst for hydrogen evolution reaction (HER), often experience unavoidable electron loss, resulting in a mismatching of electronic structure and HER behavior. Here, a Pt/WO3 catalyst consisting of Pt species strongly coupled with defective WO3 polycrystalline nanorods is rationally designed. The electronic structure engineering of Pt sites on WO3 can be systematically regulated, and so that the optimal electron-rich Pt sites on Pt/WO3 -600 present an excellent HER activity with only 8 mV overpotential at 10 mA cm-2 . Particularly, the mass activity reaches 7015 mA mg-1 at the overpotential of 50 mV, up to 26-fold higher than that of the commercial Pt/C. The combination of experimental and theoretical results demonstrates that the O vacancies of WO3 effectively mitigate the tendency of electron transfer from Pt sites to WO3 , so that the d-band center could reach an appropriate level relative to Fermi level, endowing it with a suitableΔ G H ∗ $\Delta {G_{{{\rm{H}}^ * }}}$ . This work identifies the influence of the electronic structure on catalytic activity.