Robust Ru-VO2 Bifunctional Catalysts for All-pH Overall Water Splitting

Integrated Network Cathodes by In Situ Phase Transition Break Diffusion Limitation for Zinc Ion Battery

The cathode materials set the limitation of aqueous zinc ion batteries (AZIBs) in capacity and restrict their development. Vanadium-based materials show unsatisfactory conductivity and strong interactions with Zn2+ as well as a narrow voltage window. Herein, an integrated network structure is obtained by modulating the voltage window to phase transition from VO2 to HXV2O5. This has multiple advantages: low crystallinity and abundant active sites; good electrolyte wetting; and two-electron transfer for high specific capacity. The AZIBs exhibit impressive rate performance (545 mAh g-1 at 0.1 A g-1 and 185 mAh g-1 at 20 A g-1) and cycling performance (179 mAh g-1 after 15 000 cycles at 20 A g-1), stable operation even at -20 °C (391 mAh g-1 at 1 A g-1, 97 mAh g-1 at 10 A g-1). AZIBs have high power density and high energy density based on the mass of cathode material (405 Wh kg-1 at 74 W kg-1 and 102 Wh kg-1 at 11 127 W kg-1). The pouch-type cell can run for over 500 h, has a maximum energy density of 45.5 Wh kg-1. The phase transition mechanism and energy storage mechanism are identified, which is conducive to promoting the development of cathodes for AZIBs.

Single-Atom Sb-Doped RuSbOx Bifunctional Catalysts for Ultra-Stable PEM Water Electrolyzers

Developing highly efficient and stable Pt/Ir-free bifunctional catalysts is very urgent for lowering the catalyst cost of proton exchange membrane water electrolyzer (PEMWE). Herein, a single-atom Sb-doped RuSbOx bifunctional catalyst is developed for ultra-stable PEMWE. RuSbOx exhibits excellent stability with a long-term operation of 150 h for oxygen evolution reaction (OER) and 300 h for hydrogen evolution reaction (HER) at 100 mA cm-2 in acidic media, respectively. Impressively, the PEMWE with RuSbOx as bifunctional catalysts only needs 1.72 to reach 1.0 A cm-2, and can maintain stable operation for 200 h at 200 mA cm-2. The in situ Raman and molecular probe methods reveal that the single-atom Sb doping can reconstruct the interfacial water structure on the surface of RuSbOx, resulting in an enriched supply of free water, accelerating the deprotonation process and reducing the local acidity of the catalyst surface, thereby improving the acidic OER activity and stability. Density functional theory calculations further confirm the above experimental results. In short, this work reveals that Sb is an outstanding structural stabilizer, and single-atom Sb-doping can maximize the OER stability of Ru-based catalysts in acid, which provides a useful strategy for designing ultra-stable electrocatalysts for PEMWE.

Tuning the Catalytic Activity of MoS2-x-NbSx Heterostructure Nanosheets for Bifunctional Acidic Water Splitting

Developing durable electrocatalysts with high activity for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in acidic media is critically important for clean power production. In this study, MoS2-x-NbSx heterostructure nanosheets are synthesized from a solid-state reaction method followed by liquid phase exfoliation, and their catalytic performance is optimized. The MoS2-x-NbSx heterostructure nanosheets with optimal precursors ratio exhibit promising attributes for applications in the HER and OER compared to pristine MoS2 and Nb under the same conditions. The MoS2-x-NbSx heterostructure nanosheets catalyst on glassy carbon electrodes shows the minimum overpotential of 159 mV for HER and 295 mV for OER at a current density of 10 mA cm-2 in 0.5 m H2SO4. This research offers valuable insights into the fabrication of heterostructure nanosheets and evaluates their potential as effective electrocatalysts for water splitting compared with pristine 2D materials in an acid environment.

Proton Exchange Membrane Water Splitting: Advances in Electrode Structure and Mass-Charge Transport Optimization

Proton exchange membrane water electrolysis (PEMWE) represents a promising technology for renewable hydrogen production. However, the large-scale commercialization of PEMWE faces challenges due to the need for acid oxygen evolution reaction (OER) catalysts with long-term stability and corrosion-resistant membrane electrode assemblies (MEA). This review thoroughly examines the deactivation mechanisms of acidic OER and crucial factors affecting assembly instability in complex reaction environments, including catalyst degradation, dynamic behavior at the MEA triple-phase boundary, and equipment failures. Targeted solutions are proposed, including catalyst improvements, optimized MEA designs, and operational strategies. Finally, the review highlights perspectives on strict activity/stability evaluation standards, in situ/operando characteristics, and practical electrolyzer optimization. These insights emphasize the interrelationship between catalysts, MEAs, activity, and stability, offering new guidance for accelerating the commercialization of PEMWE catalysts and systems.

Recent achievements in noble metal-based oxide electrocatalysts for water splitting

The search for sustainable energy sources has accelerated the exploration of water decomposition as a clean H2 production method. Among the methods proposed, H2 production via water electrolysis has garnered considerable attention. However, the process of H2 production from water electrolysis is severely limited by the slow kinetics of the anodic oxygen evolution reaction and large intrinsic overpotentials at the anode; therefore, suitable catalysts need to be found to accelerate the reaction rate. Noble metal-based oxide electrocatalysts retain the advantages of abundant active sites, high electrical conductivity of noble metals, and low cost, which make them promising electrocatalysts; however, they suffer from the challenge of an imbalance between catalytic activity and stability. This review presents recent research progress in noble metals and their oxides as electrocatalysts. In this review, two half-reactions (the hydrogen evolution reaction and the oxygen evolution reaction) of water electrolysis are described. Recently reported methods for the synthesis of noble metal-based oxide electrocatalysts, improvement strategies, and sources of enhanced activity and stability for these types of catalysts are presented. Finally, the challenges and future perspectives in the field are summarised. This review is expected to help improve the understanding of noble metal-based oxide electrocatalysts.

Core-shell cobalt-iron silicide electrocatalysts with enhanced bifunctional performance in hydrogen and oxygen evolution reactions

To satisfy the growing demand for green energy, hydrogen production through water electrolysis has emerged as a promising approach, making the design and synthesis of efficient and durable bifunctional electrocatalysts both critical and challenging for the advancement of hydrogen energy. In this study, we synthesized core-shell structured bifunctional transition metal silicide electrocatalysts using a magnesium thermal reduction method. During the exothermic reduction, a silicon oxide (SiOx) shell was formed, coating the active centers of the silicide and providing a protective core-shell structure. The overpotentials of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) of bimetallic cobalt iron silicide (CFS-2, Co: Fe = 1:1) catalyst in 1 M KOH at 10 mA cm-2 were 291 mV and 242 mV, respectively, with Tafel slopes of 65 and 164 mV dec-1, which were superior to single metal electrocatalysts of cobalt silicide (CS) and iron silicide (FS). The core-shell structure, with a metal silicide core and a passivating silica shell, enhances electron transfer while preventing silicon leaching and improving catalyst stability. Remarkably, after continuous operation for 24 h at a fixed current density of 10 mA cm-2, it remained stable at 1.66 V. This work represents the first successful synthesis of cobalt-iron bimetallic silicide catalysts for overall water splitting, demonstrating their significant potential for electrocatalytic applications and promoting the broader use of silicides in hydrogen production.

Controllable Detachment of Organic Ligands on Ultrathin Amorphous Nanosheets Tailors the Electron-Aggregation for Accelerated pH-Universal Hydrogen Reaction

Tailoring the local environment of catalyst surface has emerged as an effective strategy to enhance the reaction kinetics involving multiple intermediates. For hydrogen evolution reactions (HER), the driving factors for hydrogen aggregation and migration which are poorly understood in depth affects the reaction kinetics especially over a wide pH range. Inspired by the selectivity of the catalyst surface microenvironment for intermediates, an interfacial electrocatalyst composed of Ru ultrafine nanocatalysts anchored onto monolayer amorphous (a-WCoNiO) nanosheets with electron-rich microenvironment induced by an organic oleylamine ligand is designed to realize high-performance pH-universal HER. This Ru/a-WCoNiO possesses impressively low overpotentials of -13, -14, and -14 mV at 10 mA cm-2 in 0.5 m H2SO4, 1 m KOH and 1 m PBS, respectively, ranking among the best HER catalysts reported to date. Benefiting from the electron-rich microenvironment, the Ru/a-WCoNiO exhibits record-high turnover frequency (TOF) and mass activity (MA), which is more than 47.9 times higher than that of commercial 20% Pt/C. Importantly, other precious metals are loaded on a-WCoNiO and enhancing their mass current density for pH-universal HER. It is believed that this developed approach of organic modifiers tailored local microenvironment has practical significance and advantages for designing other high-performance catalysts.

Phase-Engineered Bi-RuO2 Single-Atom Alloy Oxide Boosting Oxygen Evolution Electrocatalysis in Proton Exchange Membrane Water Electrolyzer

Engineering nanomaterials at single-atomic sites can enable unprecedented catalytic properties for broad applications, yet it remains challenging to do so on RuO2-based electrocatalysts for proton exchange membrane water electrolyzer (PEMWE). Herein, the rational design and construction of Bi-RuO2 single-atom alloy oxide (SAAO) are presented to boost acidic oxygen evolution reaction (OER), via phase engineering a novel hexagonal close packed (hcp) RuBi single-atom alloy. This Bi-RuO2 SAAO electrocatalyst exhibits a low overpotential of 192 mV and superb stability over 650 h at 10 mA cm-2, enabling a practical PEMWE that needs only 1.59 V to reach 1.0 A cm-2 under industrial conditions. Operando differential electrochemical mass spectroscopy analysis, coupled with density functional theory studies, confirmed the adsorbate-evolving mechanism on Bi-RuO2 SAAO and that the incorporation of Bi1 improves the activity by electronic density optimization and the stability by hindering surface Ru demetallation. This work not only introduces a new strategy to fabricate high-performance electrocatalysts at atomic-level, but also demonstrates their potential use in industrial electrolyzers.

Spillover of active oxygen intermediates of binary RuO2/Nb2O5 nanowires for highly active and robust acidic oxygen evolution

Over-oxidation of surface ruthenium active sites of RuOx-based electrocatalysts leads to the formation of soluble high-valent Ru species and subsequent structural collapse of electrocatalysts, which results in their low stability for the acidic oxygen evolution reaction (OER). Herein, a binary RuO2/Nb2O5 electrocatalyst with abundant and intimate interfaces has been rationally designed and synthesized to enhance its OER activity in acidic electrolyte, delivering a low overpotential of 179 mV at 10 mA cm-2, a small Tafel slope of 73 mV dec-1, and a stabilized catalytic durability over a period of 750 h. Extensive experiments have demonstrated that the spillover of active oxygen intermediates from RuO2 to Nb2O5 and the subsequent participation of lattice oxygen of Nb2O5 instead of RuO2 for the acidic OER suppressed the over-oxidation of surface ruthenium species and thereby improved the catalytic stability of the binary electrocatalysts.

S- and N-Co-Doped Carbon-Nanoplate-Encased Ni Nanoparticles Derived from Dual-Ligand-Assembled Ni-MOFs as Efficient Electrocatalysts for the Oxygen Evolution Reaction

To achieve the "double carbon" goal, it is urgent to reform the energy system. The oxygen evolution reaction (OER) is a vital semi-reaction for many new energy-storage and conversion devices. Metal nanoparticles embedded in heteroatom-doped carbon materials prepared by the pyrolyzing of metal-organic frameworks (MOFs) have been a key route to obtain high-performance electrochemical catalysts. Herein, a nanocatalyst embedding Ni nanoparticles into S- and N-co-doped carbon nanoplate (Ni NPs@SN-CNP) has been synthesized by pyrolysis of a Ni-MOF precursor. The prepared Ni NPs@SN-CNP exhibits superior oxygen evolution performance with an overpotential of 256 mV to attain 10 mA cm-2 and a low Tafel slope value of 95 mV dec-1. Moreover, a self-assembled overall-water-splitting cell with Ni NPs@SN-CNP/NF||Pt-C/NF achieves a low potential of 1.56 V at 10 mA cm-2 and a high cycling stability for at least 10 h. The improvement in this performance is benefit from its large surface area, unique morphology, and the nanostructure of the electrocatalyst. This study presents a novel and simple approach to designing high-performance OER catalysts.

Loading Pt Nanoparticles on Ultrathin Amorphous Nanobelts for Enhanced Hydrogen Production

Due to unique metal-support interactions, loaded structures have been widely used in the structural design of hydrogen-extraction reaction (HER) electrocatalysts. However, the development of catalysts that are both active and stable remains a great challenge. Herein, we successfully anchored Pt nanoparticles on ultrathin nanobelts to construct a crystalline/amorphous Pt NPs/CNWOx NBs heterostructure, which possesses the dual advantages of fast electron transfer in crystalline materials and effective exposure of active sites in amorphous materials. The obtained catalyst exhibits great HER catalytic performance in both 0.5 M H2SO4 and 1 M KOH. Compared with CNWOx nanobelts, Pt-loaded Pt NPs/CNWOx NBs exhibits lower overpotentials and faster HER kinetics. For acidic and alkaline HER, the catalyst required only low overpotentials of 35 mV and 60 mV to achieve a current density of 10 mA cm-2, respectively, which is even better than that of commercial Pt/C. And Pt NPs/CNWOx NBs shows almost no degradation after long time stability tests. It is found that the composite structure of crystalline/amorphous, the heterogeneous interface and the introduction of Pt synergize with each other to achieve increased number of active sites and enhanced intrinsic activity, resulting in excellent electrocatalytic HER activity and stability.

Tuning the local S coordination environment on Ru single atoms to boost the oxygen evolution reaction

Engineering the local electronic structure of single atom catalysts (SACs) still remains challenging. In this study, a Ru-NiS2 single atom catalyst with a controlled S coordination environment, where Ru single atoms are implanted on a NiS2 nanoflower consisting of plenty of cross-linked nanosheets, has been developed via a facile atom capture strategy. Using Density Functional Theory (DFT) calculations, it has been revealed that the fine-tuned local S coordination environment can optimize the electronic structure of Ru active sites, and reduce the energy barrier of the rate-determining step for the oxygen evolution reaction (OER), thus boosting the electrocatalytic activity, such as a low overpotential of 269 mV at 10 mA cm-2. This work provides new insights into the rational regulation of the local coordination environment for SACs.

Customizing Bonding Affinity with Multi-Intermediates via Interfacial Electron Capture to Boost Hydrogen Evolution in Alkaline Water Electrolysis

Developing efficient and earth-abundant alkaline HER electrocatalysts is pivotal for sustainable energy, but co-regulating its intricate multi-step process, encompassing water dissociation, OH- desorption, and hydrogen generation, is still a great challenge. Herein, we tackle these obstacles by fabricating a vertically integrated electrode featuring a nanosheet array with prominent dual-nitride metallic heterostructures characterized by impeccable lattice matching and excellent conductivity, functioning as a multi-purpose catalyst to fine-tune the bonding affinity with alkaline HER intermediates. Detailed structural characterization and theoretical calculation elucidate that charge redistribution at the heterointerface reduces the O p-W d and H s-W d interactions vs. single nitride, thereby enhancing OH- transfer and H2 release. As anticipated, the resulting WN-NiN/CFP catalyst demonstrates a gratifying low overpotential of 36.8 mV at 10 mA/cm2 for alkaline HER, while concurrently maintaining operational stability for 1300 h at 100 mA/cm2 for overall water splitting. This work presents an effective approach to meticulously optimize multiple site-intermediate interactions in alkaline HER, laying the foundation for efficient energy conversion.

Doping Ti into RuO2 to Accelerate Bridged-Oxygen-Assisted Deprotonation for Acidic Oxygen Evolution Reaction

The development of efficient and durable electrocatalysts for the acidic oxygen evolution reaction (OER) is essential for advancing renewable hydrogen energy technology. However, the slow deprotonation kinetics of oxo-intermediates, involving the four proton-coupled electron steps, hinder the acidic OER progress. Herein, a RuTiOx solid solution electrocatalyst is investigated, which features bridged oxygen (Obri) sites that act as proton acceptors, accelerating the deprotonation of oxo-intermediates. Electrochemical tests, infrared spectroscopy, and density functional theory results reveal that the moderate proton adsorption energy on Obri sites facilitates fast deprotonation kinetics through the adsorbate evolution mechanism. This process effectively prevents the over-oxidation and deactivation of Ru sites caused by the lattice oxygen mechanism. Consequently, RuTiOx shows a low overpotential of 198 mV at 10 mA cm-2 geo and performance exceeding 1400 h at 50 mA cm-2 geo with negligible deactivation. These insights into the OER mechanism and the structure-function relationship are crucial for the advancement of catalytic systems.

Bi-doped ruthenium oxide nanocrystal for water oxidation in acidic media

There is an urgent need to develop a cost-effective and highly efficient acidic OER catalyst to support the progress of proton exchange membrane water electrolysis technology. Ruthenium-based catalysts, which possess high activity and significantly lower cost compared to iridium-based catalysts, emerge as competitive candidates. However, their suboptimal stability constrains the wide application of RuO2. Herein, we develop ultra-small Bi0.05Ru0.95O2 nanocrystal with diameter of approximately 6.5 ± 0.1 nm for acidic OER. The Bi0.05Ru0.95O2 nanocrystal electrocatalyst exhibits a low overpotential of 203.5 mV at 10 mA cm-2 and 300+ hour stability at a high water-splitting current density of 100 mA cm-2 in 0.5 M H2SO4 with a low decay rate of 0.44 mV h-1. Density functional theory (DFT) calculation results confirmed the adsorbate evolving mechanism (AEM) occurring on Bi0.05Ru0.95O2, which prevents lattice oxygen from participating in the reaction, thus avoiding the collapse of the structure. We proved that the Bi dopants could play a crucial role in not only reducing the energy barrier of the potential-determining step, but also delivering electrons to Ru sites, thereby alleviating the over-oxidation of Ru active sites and enhancing operation durability.

Nb Doping Induced the Formation of Protective Layer to Improve the Stability of Fe-Ni3S2 for Seawater Electrolysis

The seawater electrolysis to produce hydrogen is a significant topic on alleviating the energy crisis. Here, the Fe, Nb-Ni3S2 catalyst is prepared by metal-doping strategy, and it shows high oxygen evolution reaction (OER) activity in alkaline medium, and only needs 1.491 V to deliver a current density of 100 mA cm-2 in simulated seawater. Using Fe, Nb-Ni3S2 as a bifunctional catalyst, the two-electrode electrolyzer only requires a voltage of 1.751 V (without impedance compensation) to drive the current density of 50 mA cm-2, and can run over 150 h stably in the simulated seawater. Importantly, In situ Raman test demonstrates that the outstanding performance of Fe, Nb-Ni3S2 in simulated seawater is ascribed to the in situ formed sulfate protective layer induced by Nb doping, which can effectively inhibit the corrosion of chloride ion, while the protective layer is absent for Fe-Ni3S2. The stable operation of simulated seawater electrolysis under industrial current density further confirms the stability improvement mechanism of forming protective layer. In short, this study provides a new strategy of using Nb dopants inducing the formation of protective layer to enhance the stability of seawater electrolysis.

Multi-Component and Nanoporous Design toward RuO2-Based Electrocatalyst with Enhanced Performance for Acidic Water Splitting

Developing electrocatalysts with excellent activity and stability for water splitting in acidic media remains a formidable challenge due to the sluggish kinetics and severe dissolution. As a solution, a multi-component doped RuO2 prepared through a process of dealloying-annealing is presented. The resulting multi-doped RuO2 possesses a nanoporous structure, ensuring a high utilization efficiency of Ru. Furthermore, the dopants can regulate the electronic structure, causing electron aggregation around unsaturated Ru sites, which mitigates Ru dissolution and significantly enhances the catalytic stability/activity. The representative catalyst (FeCoNiCrTi-RuO2) shows an overpotential of 167 mV at 10 mA cm-2 for oxygen evolution reaction (OER) in 0.5 m H2SO4 solution with a Tafel slope of 53.1 mV dec-1, which is among the highest performance reported. Moreover, it remains stable for over 200 h at a current density of 10 mA cm-2. This work presents a promising approach for improving RuO2-based electrocatalysts, offering a crucial advancement for electrochemical water splitting.

A General Descriptor for Single-Atom Catalysts with Axial Ligands

Decoration of an axial coordination ligand (ACL) on the active metal site is a highly effective and versatile strategy to tune activity of single-atom catalysts (SACs). However, the regulation mechanism of ACLs on SACs is still incompletely known. Herein, we investigate diversified combinations of ACL-SACs, including all 3d-5d transition metals and ten prototype ACLs. We identify that ACLs can weaken the adsorption capability of the metal atom (M) by raising the bonding energy levels of the M-O bond while enhancing dispersity of the d orbital of M. Through examination of various local configurations and intrinsic parameters of ACL-SACs, a general structure descriptor σ is constructed to quantify the structure-activity relationship of ACL-SACs which solely based on a few key intrinsic features. Importantly, we also identified the axial ligand descriptor σACL, as a part of σ, which can serve as a potential descriptor to determine the rate-limiting steps (RLS) of ACL-SACs in experiment. And we predicted several ACL-SACs, namely, CrN4-, FeN4-, CoN4-, RuN4-, RhN4-, OsN4-, IrN4- and PtN4-ACLs, that entail markedly higher activities than the benchmark catalysts of Pt and IrO2 for oxygen reduction reaction and oxygen evolution reaction, respectively, thereby supporting that the general descriptor σ can provide a simple and cost-effective method to assess efficient electrocatalysts.

Asymmetric Microenvironment Tailoring Strategies of Atomically Dispersed Dual-Site Catalysts for Oxygen Reduction and CO2 Reduction Reactions

Dual-atom catalysts (DACs) with atomically dispersed dual-sites, as an extension of single-atom catalysts (SACs), have recently become a new hot topic in heterogeneous catalysis due to their maximized atom efficiency and dual-site diverse synergy, because the synergistic diversity of dual-sites achieved by asymmetric microenvironment tailoring can efficiently boost the catalytic activity by optimizing the electronic structure of DACs. Here, this work first summarizes the frequently-used experimental synthesis and characterization methods of DACs. Then, four synergistic catalytic mechanisms (cascade mechanism, assistance mechanism, co-adsorption mechanism and bifunction mechanism) and four key modulating methods (active site asymmetric strategy, transverse/axial-modification engineering, distance engineering and strain engineering) are elaborated comprehensively. The emphasis is placed on the effects of asymmetric microenvironment of DACs on oxygen/carbon dioxide reduction reaction. Finally, some perspectives and outlooks are also addressed. In short, the review summarizes a useful asymmetric microenvironment tailoring strategy to speed up synthesis of high-performance electrocatalysts for different reactions.

Constructing CoP/Ni2P Heterostructure Confined Ru Sub-Nanoclusters for Enhanced Water Splitting in Wide pH Conditions

Developing efficient electrocatalysts for water splitting is of great significance for realizing sustainable energy conversion. In this work, Ru sub-nanoclusters anchored on cobalt-nickel bimetallic phosphides (Ru-CoP/Ni2P) are constructed by an interfacial confinement strategy. Remarkably, Ru-CoP/Ni2P with low noble metal loading (33.1 µg cm-2) shows superior activity for hydrogen evolution reaction (HER) in all pH values, whose turnover frequency (TOF) is 8.7, 15.3, and 124.7 times higher than that of Pt/C in acidic, alkaline, and neutral conditions, respectively. Meanwhile, it only requires the overpotential of 171 mV@10 mA cm-2 for oxygen evolution reaction (OER) and corresponding TOF is 20.3 times higher than that of RuO2. More importantly, the Ru-CoP/Ni2P||Ru-CoP/Ni2P displays superior mass activity of 4017 mA mgnoble metal -1 at 2.0 V in flowing alkaline water electrolyzer, which is 105.1 times higher than that of Pt/C||IrO2. In situ Raman spectroscopy demonstrates that the Ru sites in Ru-CoP/Ni2P play a key role for water splitting and follow the adsorption evolution mechanism toward OER. Further mechanism studies disclose the confined Ru atom contributes to the desorption of H2 during HER and the formation of O-O bond during OER, leading to fast reaction kinetics. This study emphasizes the importance of interface confinement for enhancing electrocatalytic activity.

Robust and Corrosion-Resistant Overall Water Splitting Electrode Enabled by Additive Manufacturing

Electrolysis of water has emerged as a prominent area of research in recent years. As a promising catalyst support, copper foam is widely investigated for electrolytic water, yet the insufficient mechanical strength and corrosion resistance render it less suitable for harsh working conditions. To exploit high-performance catalyst supports, various metal supports are comprehensively evaluated, and Ti6Al4V (Ti64) support exhibited outstanding compression and corrosion resistance. With this in mind, a 3D porous Ti64 catalyst support is fabricated using the selective laser sintering (SLM) 3D printing technology, and a conductive layer of nickel (Ni) is coated to increase the electrical conductivity and facilitate the deposition of catalysts. Subsequently, Co0.8Ni0.2(CO3)0.5(OH)·0.11H2O (CoNiCH) nanoneedles are deposited. The resulting porous Ti64/Ni/CoNiCH electrode displayed an impressive performance in the oxygen evolution reaction (OER) and reached 30 mA cm-2 at an overpotential of only 200 mV. Remarkably, even after being compressed at 15.04 MPa, no obvious structural deformation is observed, and the attenuation of its catalytic efficiency is negligible. Based on the computational analysis, the CoNiCH catalyst demonstrated superior catalytic activity at the Ni site in comparison to the Co site. Furthermore, the electrode reached 30 mA cm-2 at 1.75 V in full water splitting conditions and showed no significant performance degradation even after 60 h of continuous operation. This study presents an innovative approach to robust and corrosion-resistant catalyst design.

Designing 3d Transition Metal Cation-Doped MRuOx As Durable Acidic Oxygen Evolution Electrocatalysts for PEM Water Electrolyzers

The continuous dissolution and oxidation of active sites in Ru-based electrocatalysts have greatly hindered their practical application in proton exchange membrane water electrolyzers (PEMWE). In this work, we first used density functional theory (DFT) to calculate the dissolution energy of Ru in the 3d transition metal-doped MRuOx (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) to evaluate their stability for acidic oxygen evolution reaction (OER) and screen out ZnRuOx as the best candidate. To confirm the theoretical predictions, we experimentally synthesized these MRuOx materials and found that ZnRuOx indeed displays robust acidic OER stability with a negligible decay of η10 after 15 000 CV cycles. Of importance, using ZnRuOx as the anode, the PEMWE can run stably for 120 h at 200 mA cm-2. We also further uncover the stability mechanism of ZnRuOx, i.e., Zn atoms doped in the outside of ZnRuOx nanocrystal would form a "Zn-rich" shell, which effectively shortened average Ru-O bond lengths in ZnRuOx to strengthen the Ru-O interaction and therefore boosted intrinsic stability of ZnRuOx in acidic OER. In short, this work not only provides a new study paradigm of using DFT calculations to guide the experimental synthesis but also offers a proof-of-concept with 3d metal dopants as RuO2 stabilizer as a universal principle to develop high-durability Ru-based catalysts for PEMWE.

A restricted dynamic surface self-reconstruction toward high-performance of direct seawater oxidation

The development of highly efficient electrocatalysts for direct seawater splitting with bifunctionality for inhibiting anodic oxidation reconstruction and selective oxygen evolution reactions is a major challenge. Herein, we report a direct seawater oxidation electrocatalyst that achieves long-term stability for more than 1000 h at 600 mA/cm2@η600 and high selectivity (Faraday efficiency of 100%). This catalyst revolves an amorphous molybdenum oxide layer constructed on the beaded-like cobalt oxide interface by atomic layer deposition technology. As demonstrated, a new restricted dynamic surface self-reconstruction mechanism is induced by the formation a stable reconstructed Co-Mo double hydroxide phase interface layer. The device assembled into a two-electrode flow cell for direct overall seawater electrolysis maintained at 1 A/cm2@1.93 V for 500 h with Faraday efficiency higher than 95%. Hydrogen generation rate reaches 419.4 mL/cm2/h, and the power consumption (4.62 KWh/m3 H2) is lower than that of pure water (5.0 KWh/m3 H2) at industrial current density.