Nickel (Ni) is a promising catalyst for electrochemical urea oxidation reactions. However, its strong chemisorption of CO2 and the tendency for uncontrollable structural reconstruction during catalysis have limited the exploration of Ni-based catalysts in electrocatalytic urea synthesis. Herein, we propose a co-modification strategy for Ni-mSiOx using polydopamine (PDA) and polyethyleneimine (PEI) to enable efficient electrocatalytic co-reduction of nitrate and CO2 for urea synthesis. The incorporation of stable Niu2013Ou2013Si active sites effectively balanced competing reaction pathways, while dual polymer modification optimized the surface electronic structure, promoted the formation of pyrrolic/pyridinic nitrogen species (ProN/PN, 86.7%), and accelerated Cu2013N coupling kinetics. The resulting PDA/PEI-Ni-mSiOx catalyst achieved a urea production rate of 2513 u03BCgu00B7hu22121u00B7mgcatu22121, a Faradaic efficiency of 28.6%, and a urea selectivity of 54.2%. Notably, the catalyst retained over 90% of its activity after 39 h of continuous operation, with no observable structural degradation following repeated cycling. This work presents a robust strategy for the rational design of high-performance, durable Ni-based catalysts for urea electrosynthesis and provides mechanistic insights into the structureu2013activity relationships at polymeru2013metal oxide interfaces.

The rational design of acid-stable, iridium-free electrocatalysts for the oxygen evolution reaction (OER) is critical for advancing proton exchange membrane water electrolysis (PEMWE), yet balancing activity and durability remains a formidable challenge. Herein, we report a RuO2/Mn3O4 heterojunction with engineered oxygen vacancies (Ov) as a durable, high-performance iridium alternative. Engineering triggers substantial electron transfer from Mn3O4 to RuO2, lowering the average Ru oxidation state from +3.69 to +3.34 and increasing d-band occupancy from 4.23 to 4.50. This enhanced occupancy strengthens Ru-O covalency via intensified coupling with O 2p orbitals, corroborated by density functional theory calculations showing a reduced energy barrier of potential-determining step by 0.62 eV. In situ spectroscopy further reveals a distinctive dual H2O adsorption configuration at adjacent Ru-Ov sites, enabling direct O-O coupling and promoting a more efficient OER pathway. Consequently, the optimized RuO2/Mn3O4-Ov catalyst achieves an exceptionally low overpotential of 185 mV at 10 mA cm- 2 and a turnover frequency of 4.33 s- 1 at 185 mV-188-fold higher than commercial RuO2. Notably, it maintains stable operation for over 200 h at 100 mA cm- 2 in 0.1 M HClO4, highlighting its promise for replacing iridium catalysts in PEMWE applications.

The thermodynamic and kinetic mismatch between oxidative and reductive half-reactions represents a central barrier in photocatalysis, largely due to the absence of well-defined and functionally differentiated active sites. Herein, we construct Co and Pt redox dual-site catalysts (CoPt RDSCs), featuring nonbonded yet spatially close single atoms anchored on carbon nitride for H2O2 photosynthesis, thereby enabling site-specific utilization of photogenerated holes and electrons. The Co sites act as the hole centers that drive the four-electron water oxidation reaction, whereas the Pt sites serve as the electron centers that catalyze the two-electron oxygen reduction reaction, each lowering the thermodynamic barrier of its respective half-reaction. Crucially, the proximity of these electronically decoupled sites enables the directed migration of the oxidation products (O2 and H+) generated at Co sites to neighboring Pt sites, establishing an internal redox-coupling pathway that accelerates the overall reaction kinetics. Multidimensional in situ spectroscopy, transient photodynamics, and theoretical analyses confirm that each half-reaction proceeds on the designated site independently yet synergistically. Consequently, the CoPt RDSCs achieve a 19.33% apparent quantum efficiency at 420 nm and a 1.46% solar-to-chemical conversion efficiency for H2O2 synthesis in pure water, outperforming most of the reported photocatalysts under comparable conditions. Spatial engineering of redox active sites establishes a general design principle for constructing high-performance photocatalysts capable of coordinating oxidative and reductive transformations.

Single-atom catalysts with metal-N4 sites demonstrate good activity in the oxygen reduction reaction (ORR), yet the symmetric electronic structure limits its ability to differentially regulate oxygen-containing intermediates, resulting in sluggish kinetics. To address this, we have developed an axial chlorine-mediated strategy to break the symmetry of the copper-N4 structure, thereby achieving superior ORR activity. Ax-Cl-Cu/NC catalyst was synthesized by coordinating an axial chlorine atom to the Cu-N4 sites on an NC support. The as-prepared Ax-Cl-Cu/NC catalyst exhibits outstanding ORR performance, achieving nearly 99% four-electron selectivity and a large mass activity of 4,430.6 A gmetal-1 at 0.85 V - 67.4 times higher than Pt/C (65.73 A gmetal-1). The superior performance of the Ax-Cl-Cu/NC catalyst is further demonstrated in a lab-assembled Zinc-air battery, which achieves stable operation for over 100 h. A series of experimental characterizations confirmed that the introduction of an axial chlorine atom reduced the electron density of the Cu center, alleviating the over-stabilization of oxygen intermediates and facilitated the cleavage of the O-O bond. This work establishes a new paradigm for designing high-efficiency non-precious metal ORR catalysts.

Electrocatalytic nitrate reduction to ammonia (NO3RR) offers a promising route to couple nitrate remediation with sustainable NH3 production, but practical implementation remains limited by sluggish charge transfer, parasitic hydrogen evolution, and insufficient catalyst durability. Here, we report a phase/defect codesign strategy in which Zn substitution stabilizes the monoclinic CuWO4 framework while simultaneously enriching oxygen vacancies, creating a vacancy-rich and structurally robust heterometal oxide catalyst for efficient NO3RR. This dual-control approach differs fundamentally from doping-only or defect-only strategies because it not only tunes the local electronic structure and intermediate binding, but also preserves the catalytically favorable framework under prolonged electrolysis. The optimized Zn1.0-CuWO4-140 delivers an NH3 yield of 51.8 mg h-1 mgcat -1 with a Faradaic efficiency (FE) of 84.2% at -1.3 V vs RHE in 0.1 M KOH and 0.1 M KNO3, and retains stable performance for 60 h while maintaining the monoclinic phase. Large-area testing in a 5 & times; 5 cm2 flow cell further verifies robust operation under continuous-flow conditions. DFT calculations reveal that Zn substitution lowers the energetic demand for key hydrogenation steps and kinetically favors *H addition over pathways leading to *N/N2 formation. Beyond CuWO4, this work highlights phase/defect codesign as a general strategy for heterometal oxides in NO3RR and other multistep electrocatalytic reactions, where activity, selectivity, and durability must be optimized simultaneously.

Nickel (Ni) is a promising catalyst for strong chemisorption of CO2 and the tendency for uncontrollable structural reconstruction during catalysis have limited the exploration of Ni-based catalysts in (PDA) and polyethyleneimine (PEI) to enable efficient electrocatalytic co-reduction of nitrate and CO2 for urea synthesis. The incorporation of stable Ni-O-Si active sites structure, promoted the formation of pyrrolic/pyridinic coupling kinetics. The resulting PDA/PEI-Ni-mSiOx catalyst achieved a urea production rate of 2513 mu gh-1mgcat-1, a Faradaic efficiency of 28.6%, and a urea selectivity of 54.2%. Notably, the catalyst retained over 90% of its activity after 39 h of continuous operation, with no observable structural degradation following repeated cycling. This work presents a robust strategy for the rational design of high-performance, durable Ni-based catalysts for urea electrosynthesis and provides mechanistic insights into the structure-activity relationships at polymer-metal oxide interfaces.

The acidic oxygen reduction reaction (ORR) as the soul process in proton-exchange membrane fuel cells, faces fundamental limitations due to linear scaling relations (LSR) among adsorption energies at active sites. This intrinsic constraint typically leads to trade-offs between activity enhancement and compromised selectivity/stability. Here, the second-shell coordination engineering was proposed to construct the heteronuclear twin-site FeCu (TW-FeCu) catalyst, that can directly cleave the O-O bond without formation of sluggish *OOH species to disrupt the LSR of intermediate adsorption and minimize the activation energy for O-O bond scission. This well-designed Tw-FeCu catalyst demonstrates superior activity with a half-slope potential (E 1/2) of 0.841 V and 4e- selectivity nearly 100% in acidic media, demonstrating promising potential as the energy device of H2/O2 fuel cells (515 mW cm-2). A series of characterizations revealed that second-shell Cu coordination enhances Fe charge distribution via an electronic bridge channel, thereby suppressing metal leaching, while simultaneously enabling a twin-site cooperative coupling pathway to accelerate reaction kinetics. This work establishes a rational design strategy for highly efficient atomically dispersed ORR catalysts that circumvent LSR limitations.

Electrochemical seawater electrolysis powered by renewable energy is a highly promising route toward sustainable hydrogen production, mitigating both energy shortages and carbon emissions. However, chloride-induced corrosion and competitive chlorine evolution reactions lead to metal site dissolution, severely impairing durability, especially at industrial-level current densities. Here, we report a nitrite-incorporated cobalt-iron layered double hydroxide (CoFe-NO2−-LDH) electrocatalyst that exhibits exceptional activity and stability for seawater splitting. The nitrite anion acts as an electronic pump: it accepts electrons to facilitate the formation of high-valence Fe species essential for initial OER activation, and donates electrons under high potential to suppress oxidative dissolution. Moreover, the negatively charged nitrite generates an electrostatic repulsion field that effectively repels chloride ions, protecting metal active sites from corrosion and segregation. The in situ characterization confirms that nitrite doping weakens the Fe–O covalency, which suppresses lattice oxygen participation and promotes a stable adsorbate-evolving mechanism, consequently leading to significantly enhanced operational stability. When used as an anode, the CoFe-NO2−-LDH catalyst achieves over 1000 h of stable operation at 1000 mA cm−2 in seawater electrolysis, demonstrating great potential for practical applications.

The photocatalytic oxygen reduction reaction (ORR) for hydrogen peroxide (H2O2) production via the two-electron pathway offers an environmentally friendly oxidant and a clean fuel. However, the challenge exists in optimal oxygen (O2) adsorption capacities and maintaining O–O bond during O2 activation. Herein, we present a zinc single-atom catalyst (Zn/VN-CN) incorporating nitrogen vacancies (VN), which is designed to modulate the electronic structure of the photocatalyst, leading to optimized O2 adsorption energy and a remarkable enhancement in H2O2 yield. Benefitting from the synergistic effect between nitrogen vacancies and Zn single atoms, the optimized Zn/VN-CN catalyst exhibits a photocatalytic H2O2 production rate of 2.399 mmol g−1 h−1 under visible-light irradiation, representing a 12-fold enhancement compared to pristine g-C3N4 (CN), along with a high H2O2 selectivity of 87.4

Iridium‐based electrocatalysts are commonly regarded as the sole stable operating acidic oxygen evolution reaction (OER) catalysts in proton‐exchange membrane water electrolysis (PEMWE), but the linear scaling relationship (LSR) of multiple reaction intermediates binding inhibits the enhancement of its activity. Herein, the compressive strain and oxygen vacancy effect exists in iridium dioxide (IrO 2 )‐based catalyst by a doping engineering strategy for efficient acidic OER activity. In situ synchrotron characterizations elucidate that compressive strain can enhance Ir─O covalency and reduce the Ir─Ir bond distance, and oxygen vacancy (O v ) as an electronic regulator causes rapid adsorption of water molecules on the Ir and adjacent Ov (Ir─O v ) pair site to be coupled directly into * O─O * intermediates. Importantly, hence, volcano‐shape curves are established between the compressive strain/oxygen vacancy and OER current using OER as the probe reaction. Theoretical calculation reveals Ni dopant can modulate Ir 5 d ‐ and O 2 p ‐band centers for increasing overlap of Ir 5 d and O 2 p orbits to trigger a continuous metal site‐oxygen vacancy synergistic mechanism (MS‐O V SM) pathway, successfully breaking the LSR of intermediates binding during OER. Therefore, the resultant proton‐exchange membrane water electrolysis (PEMWE) device fabricated using T‐0.24Ni/IrO 2 delivers a current density of 500 mA cm −2 and operates stably for 500 h.

Heteroatom occupancy plays a key role in the precise modulation of specific material regions by introducing foreign elements into the main material matrix, yet it urgently requires further understanding from a spatial perspective. Herein, we propose a “satellite atom-spinel crystal” concept by synthesizing model catalysts with Fe atoms strategically positioned at two different spatial positions of spinel Co3O4 (satellite-Fe at Co3O4 (Fe(Sat)-Co3O4) and Fe-doped Co3O4 (Co3Fe(In)O4)), through which a new catalytic phenomenon is found. Multidimensional in situ spectroscopies revealed that Fe(Sat)-Co3O4 overcomes the crystal field potential energy (FeSat–O > FeSat–O–CoOh) and exhibits 1

Achieving precise control of the electronic environment of transition metal compounds is important for improving the efficiency of electrocatalytic oxygen reduction reaction (ORR) but continues a formidable challenge. Herein, we present a novel Fe2P/Fe heterostructure catalyst with abundant dislocation defects, where the oxidation state of Fe shift from 0.11 to 0.97, leading to an enhanced ORR performance. In situ FTIR and DFT showed that the dislocation-rich heterojunction catalysts enhanced the desorption of *OOH intermediates, facilitated the hydrogenation process of *O, and improved the kinetic process of the 4e-reaction. Consequently, the developed Fe2P/Fe catalyst exhibited a mass activity of 164.3 A gmetal-1, which is over three times greater than the traditional Pt/C catalyst that measured 53.6 A gmetal-1, highlighting its remarkable efficacy. This significant activity enhancement was accompanied by 99.56 % 4e-selectivity and half-slope potential (E1/2 = 0.90 V). In addition, the catalyst also performs excellent power density (150.4 mW cm-2) in zinc-air batteries (ZABs) and maintains long-term stability after 130 h of continuous charging and discharging. This work on dislocation-rich non-noble metal catalysts provides new insights into oxygen reduction catalysts.

The electrochemical conversion of nitrate,a widespread water pollutant,into valuable ammonia represents a green and decentralized approach to ammonia synthesis.However,the sluggish multielectronproton coupling path and the low reactive species（nitrate and proton） concentration at the catalyst interface inhibit the efficiency of ammonia production from nitrate reduction reaction（NitRR）.Herein,we introduce a novel iron-based tandem catalyst encapsulated by reduced graphene oxide（denoted as Fe-rGO）,with a superior ammonia production rate of 47.815 mg h -1 mg ca t-1 and a high Faraday efficiency（FE） of 96.51% at an applied potential of-0.5 V.It also delivers a robust stability with FE above90% under a current density of 250 mA cm -2 for 50 h.In situ X-ray absorption spectroscopy reveals that the FeO x is dynamically translated to Fe 0 site concurrently with the enhancement of the NH 3 production rate,suggesting the Fe 0 site as hydrogenation active center.The asymmetric distribution of surface charges of rGO not only enriches nitrate ions at the catalytic interface and promotes the hydrogenation process in NitRR,but also protects the iron species and ensures their stability during electrolysis.The Zn-NO 3 - battery demonstrates an impressive FE of 88.6%,highlighting its exceptional potential for practical applications.

The selective electrosynthesis of hydrogen peroxide (H2O2) via the oxygen reduction reaction (ORR) holds significant promise for sustainable chemical production. In this study, we optimized the oxygen functional groups on carbon black (CB) to modulate the bubble-water/catalyst interface microenvironment, thereby enhancing the electrosynthesis of H2O2. A simple hydrothermal method was employed to functionalize the carbon black surface, and the oxygen content was systematically adjusted by varying the temperature and time. The electrochemical performance of the resulting catalysts was evaluated, with CB-85-6 h demonstrating the highest H2O2 productivity (3302.23 mmol gcat-1 h-1) and selectivity (90.1%). EDS, XPS, Raman spectroscopy, and contact angle analysis demonstrated that the introduction of oxygen functional groups enhanced the surface hydrophobicity, facilitating the adsorption and activation of oxygen. Density functional theory (DFT) calculations further confirmed that the COOH at the edge of graphene, C-O-C at the basal 2 and C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 O at the edge optimize the binding energy of the reaction intermediates, improving both the selectivity and efficiency of H2O2 production. This work provides valuable insights into the design of highly efficient catalysts for electrocatalytic H2O2 synthesis.

The electrochemical reduction of nitrate (NO3-) to ammonia (NH3) (NO3RR) represents an environmentally sustainable strategy for NH3 production while concurrently addressing water pollution challenges. Nevertheless, the intrinsic complexity of this multi-step reaction severely constrains both the selectivity and efficiency of NO3RR. Copper-based electrocatalysts have been extensively investigated for NO3RR but often suffer from nitrite (NO2-) accumulation, which stems from insufficient NO3-adsorption strength. This limitation often leads to rapid catalyst deactivation, hindered hydrogenation pathways, and reduced overall efficiency. Herein, we report a one-step green chemical reduction method to synthesize PtCuSnCo quarternary alloy nanoparticles with homogeneously distributed elements. Under practical NO3-concentrations, the optimized catalyst exhibited an impressive Faradaic efficiency approaching 100% and an outstanding selectivity of 95.6 +/- 2.9%. Mechanistic insights uncovered that SnCo sites robustly facilitated NO3-adsorption, complemented by the proficiency of PtCu sites in NO3-reduction. The synergistic spatial neighborhood effect between SnCo and PtCu sites efficiently stabilizes NO3-deoxygenation and suppresses NO2-accumulation. This tandem architecture achieves a finely tuned balance between adsorption strength and deoxygenation kinetics, enabling highly selective and efficient NO3RR. Our findings emphasize the indispensable role of engineered multi-metallic catalysts in overcoming persistent challenges of NO3RR, paving the way for advanced NH3 synthesis and environmental remediation. (c) 2025, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

The spatial distance between active sites is a critical factor governing hydroxyl (*OH)-group-mediated synergies in multiphase electrocatalysis. But direct experimental evidence correlating atomic-scale spatial arrangement with synergistic behavior, reaction kinetics, and catalytic mechanisms remains scarce. Using the acidic oxygen evolution reaction (OER) as a model, this study employs in situ synchrotron radiation infrared spectroscopy to demonstrate that adjacent active sites enable direct *OH coupling, forming the *O-O* intermediate. Complementary in situ X-ray absorption spectroscopy and theoretical calculations reveal that adjacent Ir sites induce electronic restructuring. This optimized electronic configuration facilitates unlocking a dual-site synergistic mechanism. Conversely, isolated sites (at a farther distance) exhibit spatial inaccessibility of *OH intermediates, forcing a higher-energy pathway via *OOH formation. These findings establish a universal paradigm for manipulating interfacial *OH dynamics through atomic-scale spatial engineering, applicable to diverse reactions including hydrogen evolution, oxygen reduction, and CO2 reduction.

The strategic regulation of the electronic properties in single-atom sites through integrating metal nanoparticles emerges as a promising route to enhance the oxygen reduction reaction (ORR) performance. Here, a symbiotic Co catalyst (CoSA/NP-NC) is successfully developed in which Co single atoms and Co nanoparticles are co-anchored within a nitrogen-doped carbon matrix. It demonstrates excellent ORR catalytic activity, with a half-wave potential (E1/2) of 0.88 V relative to the reversible hydrogen electrode and a kinetic current density (Jk) of 20.67 mA cm- 2 at 0.80 V, surpassing the performance of standard commercial Pt/C catalysts. Advanced in situ synchrotron infrared spectroscopy and X-ray absorption fine structure analysis unravel the tandem synergetic reaction mechanism of SA and NP in symbiotic Co sites, that is, oxygen molecules first adsorbed on the Co SA site with low d-band electron occupancy to achieve rapid activation, and then transferred to the electron-rich Co NP for the reduction reaction. This symbiotic synergy promotes the O-O bond breaking in *OOH to form *O intermediates, thereby enhancing the durability and activity of the ORR.