Tailoring the surface acidity and electronic structure of (Ce, La)PO4 via Fe modification for low-temperature NH3-SCR

Cuδ+ species are recognized as optimal active sites for the electrocatalytic CO2 reduction reaction. While metal-support interactions (MSIs) modulate the local microenvironment of Cuδ+, the intrinsic contribution of support crystallographic facets to these interactions remains obscured by interfering oxygen vacancies. In this work, we present a definitive study decoupling the facet effect from vacancy-related variables by utilizing CeO2 supports with comparable oxygen vacancy concentrations. Our findings reveal that Cu single atoms supported on various CeO2 facets follow a pronounced facet-dependent stability order of Cu/CeO2-(110) > Cu/CeO2-(100) > Cu/CeO2-(111), yet exhibit facet-independent methane Faraday efficiency (∼80% at -200mA/cm2). Mechanistic studies unravel this dichotomy, revealing that identical Cu coordination environments drive the uniform initial activity, whereas distinct surface electronic structures dictate long-term stability by modulating facet-dependent MSIs. Specifically, the (110) facet exhibits the strongest MSI, acting as a robust "electron buffer" that securely anchors high-valent Cuδ+ species and effectively retards their irreversible reductive agglomeration into clusters. By establishing an unambiguous structure-performance relationship under single-variable conditions, this study provides a rational geometric descriptor for designing long-lasting CO2 conversion catalysts.

ABSTRACT Reversible protonic ceramic cells (R‐PCCs) enable efficient and reversible steam‐to‐hydrogen conversion. However, their air electrodes rely on proton‐mediated reactions in both electrolysis and fuel cell modes, requiring intrinsically hydrophilic oxides to incorporate water as a proton source. Conventional air electrodes suffer from poor water uptake under low water partial pressure ( p H 2 O), necessitating concentrated steam that compromises both system stability and energy efficiency. Here, we develop a BaCo 0.45 Fe 0.45 In 0.1 O 3‐δ air electrode for R‐PCCs through rational screening of BaFeO 3 ‐based oxides. This material exhibits an unprecedented proton concentration of 10.5 mol% at p H 2 O = 0.02 atm at low temperatures. Notably, steam exposure induces in situ exsolution of BaCoO 3‐δ nanocatalysts, enhancing electrochemical activity. The steam‐driven reconstruction process is systematically elucidated using depth‐profiling characterizations combined with DFT calculations. Benefiting from its super‐hydrophilic property and optimized surface electronic structure, R‐PCCs incorporating this air electrode deliver a remarkable current density of 2615 mA cm −2 at 1.3 V and a peak power density of 1.02 W cm −2 at 600°C, and maintain high Faradaic efficiency across a wide p H 2 O range of 0.006–0.47 atm. This work establishes a hydrophilicity‐driven air‐electrode design strategy for efficient hydrogen production under ultra‐low steam conditions, offering a viable pathway for deployment in freshwater‐scarce regions.

Mg-CO2 battery is emerging as a promising energy storage system that simultaneously converts CO2 into value-added products. However, its practical application is hindered by formation thermodynamically stable and electrically insulating discharge product MgCO3, which severely limits energy efficiency of Mg-CO2 battery. Herein, we report an electron-localized Ru61Ni39 nanosheet assembly catalyst that overcomes these limitations by precisely engineering the surface electronic structure for achieving precise tuning of product from MgCO3 to MgC2O4 of Mg-CO2 battery. We demonstrate that electron transfer from Ni to Ru creates the localized electron at the Ru sites, weakening MgC2O4 binding and suppressing its conversion to MgCO3, thereby enabling reversible formation and decomposition of MgC2O4 and mitigating cathode passivation. The Mg-CO2 battery incorporating the electron-localized Ru61Ni39 nanosheet assembly catalyst achieves an ultralow charge overpotential of 0.07V and a record-high energy conversion efficiency of 94.1%, with the stable cycling for over 580h. In situ electrochemical spectroscopy and theoretical studies reveal that the electron-localized between Ru and Ni stabilizes the product intermediates (C2O4 2-) and prevents the MgC2O4 conversion to MgCO3.

Developing bifunctional electrocatalysts in alkaline water splitting remains a significant challenge for hydrogen production. Herein, a novel hierarchical electrocatalyst by coupling rhenium disulfide/nickel sulfide heterostructure with the two-dimensional metal-organic framework-derived CoS2 nanoarrays (CoS2@ReNiS) is designed. The hierarchical structure provides abundant active sites, and heterogeneous interfaces can facilitate electron transfer. The surface electronic structure is optimized by coupling multiple metal sulfides, and the interfacial interaction is favorable to enhancing catalytic activity. As confirmed by microscopic and spectroscopic analysis, the interfacial engineering between multiple metal sulfides creates defect-rich active sites and modulates local electronic environment to enhance catalytic activity, and the boosted catalytic activity and catalytic mechanism are elucidated by the theoretical calculation. Only 85 and 256 mV of overpotential are required for CoS2@ReNiS during the hydrogen and oxygen evolution reactions in alkaline electrolytes at 10 mA cm-2. Small Tafel slopes and low charge transfer resistance display the rapid reaction kinetics. For the symmetric CoS2@ReNiS||CoS2@ReNiS electrolyzer, the voltage is only 1.57 V at 10 mA cm-2, maintaining outstanding catalytic stability for 24 h. This work demonstrates an effectiveness of multicomponent heterostructure design and interface engineering strategies for developing advanced bifunctional electrocatalysts for water splitting.

Noble-metal-free electrocatalysts are inexpensive and exhibit low onset potential, adequate stability, and excellent conductivity, making them highly attractive for advancing direct formic acid fuel cells. In this study, we modulated the surface electronic structure of copper aerogel by incorporating an ultra-low amount of nickel, resulting in the formation of a Cu98Ni2 aerogel catalyst. The compositional, morphological, structural, and electrochemical properties of the as-prepared electrocatalyst were extensively studied using XPS, TEM, SEM/EDX, SEM, XRD, ICP-OES, and CV techniques. The Cu98Ni2 aerogel exhibits mass activity values that are 13.3, 2.8, and 4.5 times higher than those of undoped Cu, Cu95Ni5, and Cu92Ni8 aerogels, respectively, along with onset potentials that are negatively shifted by 45, 25, and 12 mV. Notably, the Cu98Ni2 aerogel maintains about 82% of its initial steady-state current density after 10 hours of formic acid oxidation, indicating a significant improvement in catalyst performance. Furthermore, Cu98Ni2 attains the smallest Tafel slope (81.5 mV dec-1) and apparent activation energy (23.8 kJ mol-1), suggesting faster and easier charge transfer kinetics for formic acid oxidation compared to undoped Cu and Cu aerogels with higher Ni loading. The outstanding performance of the electrocatalyst in formic acid oxidation is mainly attributed to superior conductivity, effective mass and electron transfer, minimal CO poisoning, and the synergistic effects of its constituents. This study promotes the production of highly stable and efficient electrocatalysts made from non-precious metals.

Abstract Designing active and stable catalytic electrodes is essential for large-scale hydrogen production through water electrolysis. In this work, we successfully fabricated a catalytic electrode (Pt-NiB/MS) via a one-step, rapid, and mild electroless plating method, incorporating ultra-trace platinum-decorated NiB alloy onto a corrosion-resistant and cost-effective sponge substrate. This electrode is comparable to industrial-grade three-dimensional nickel foam and Raney nickel substrates. The precise modulation of Pt enables the design of tunable three-dimensional electrodes and the fabrication of ultra-rigid structures that can serve as robust alternatives to commercial electrodes. Doping with merely 0.02% Pt effectively regulates the electronic structure of the NiB alloy surface, facilitating the generation and transformation of reaction intermediates. The electrode exhibits outstanding HER/OER activity, with trace Pt incorporation reducing the overall water-splitting overpotential by 40 mV at a current density of 200 mA cm −2 , enabling operation at only 1.846 V. Furthermore, it demonstrates remarkable long-term stability, maintaining performance over 720 h at a current density of 0.5 A cm −2 . More importantly, this preparation strategy enables a universal, mild, and rapid synthesis approach for various noble metals (e.g., Ru, Ir), expanding its applicability. The developed electrode exhibits excellent electrocatalytic performance and potential for integration into anion exchange membrane systems. This strategy provides a promising alternative to industrial-grade Raney nickel.

Phototribology of copper surfaces

Tuning surface electronic structure of (CuGa) Zn1‒2Ga2S4 photocatalyst for efficient nitrate-to-ammonia conversion

Abstract We report scanning tunneling microscopy and spectroscopy on the kagome metal EuTi 3 Bi 4 . Cleavage produces atomically flat Eu-terminated surfaces. Spectroscopy shows characteristic states from van Hove singularities and flat bands. Quasiparticle interference imaging reveals C 2 -symmetric patterns that evolve with energy, reflecting the electronic anisotropy and band dispersion expected for the kagome-derived surface states. This study provides a real-space view of the surface electronic structure in EuTi 3 Bi 4 .

Developing highly efficient and stable catalysts for electrochemical carbon dioxide reduction reaction (CO2RR) remains a significant challenge, particularly for transition metal-based systems that often suffer from excessive hydrogen evolution and catalyst degradation. In this work, we report a carbon-coated NiFe alloy (NiFe@NC) synthesized via a substrate-anchored pyrolysis strategy, in which the carbon shell serves as an electronic modulator and protective layer. DFT calculations and in situ spectroscopic analysis reveal that the carbon layer induces notable electronic reconstruction at the NiFe surface, weakening the back-donation to the anti-bonding orbitals of the *CO intermediate, thus facilitating *CO desorption and improving CO2RR kinetics. Meanwhile, the carbon layer also suppresses undesired *H adsorption while protecting the catalyst from deactivation under long-term operation. As a result, the NiFe@NC catalyst achieves stable operation at 500mA cm-2 for 250 h in a membrane electrode assembly (MEA) system, outperforming most previously reported transition-metal-based catalysts. This work provides a practical strategy for tuning surface electronic structures to overcome the intrinsic limitations of conventional transition metal CO2RR catalysts.

Effects of Mo addition on the mechanical properties and Cl− corrosion behavior of TA18 titanium alloy: Experimental and DFT computational study

Recent progress of surface/interface modification of transition metal oxides for enhancing electrochemical energy storage and conversion activity

Regulating surface active hydrogen on CeO2 for efficient electrochemical synthesis of hydroxylamine from nitrates.

The modulation of defects and edge site reactivity significantly influences the activity of catalysts in various electrochemical processes. However, the role of these factors in bismuth-based electrocatalysts for the CO2 reduction reaction (CO2RR) has not been adequately realized. To elucidate the effects of these phenomena on the CO2RR, we synthesize Bi2Se3-xTex (x = 0, 1, 1.5, 2, 3) alloyed nanosheets by varying the composition of selenium (Se) and tellurium (Te). Our approach simultaneously modifies their surface morphology and electronic structure, effectively regulating the CO2RR activity. The presence of rich defects in the alloyed nanosheets leads to the formation of a high density of vertically aligned edges. The chalcogen vacancies in the alloyed nanosheets introduce localized defect states within the bandgap, which facilitates the accumulation of electrons at the active sites and significantly lowers the kinetic barriers for CO2RR. These defect-induced geometric and electronic modifications optimize the CO2RR performance, achieving a high Faradaic efficiency for formate. Furthermore, when alloyed nanosheets are coupled with a photoanode, the integrated photoelectrochemical CO2RR device exhibits an average applied bias photon-to-current efficiency of up to 12.1% for formate over 50 h of operation. Our study offers a promising pathway for designing high-performance CO2RR catalysts through chalcogen alloying.

The rational design of selective, earth-abundant Ni-based catalysts for the reverse water–gas shift (RWGS) reaction is often hampered by an incomplete understanding of their operando active states. This study reveals that the CO2 hydrogenation selectivity over Ni–Zn catalysts is governed by a support-dependent, reaction-induced dynamic restructuring, rather than by any static, preformed sites. Through a combination of in situ characterization and theoretical calculations, we demonstrate that the active Ni–Zn intermetallic core encapsulated by ZnO forms dynamically only under the RWGS atmosphere on ZrO2 and TiO2 supports, but not on Al2O3 or during mere H2 reduction. Crucially, we identify in situ-generated CO as the essential inducer of this reconstruction, likely via facilitating ZnO reduction. Furthermore, the product selectivity (CO vs CH4) is dictated by the kinetic competition between CO desorption and its deep hydrogenation, a principle quantitatively linked to the evolved electronic structure of the active surface. This work shifts the paradigm toward designing catalysts that evolve into optimal structures in operando and provides a fundamental kinetic framework for selective CO2 conversion.

Copper (Cu)-based catalysts are widely employed in electroreduction of carbon dioxide (CO2ER) because of their cost-effectiveness and versatility in producing multi-carbon products. However, improving the product selectivity, especially toward C2 species (hydrocarbon containing two carbon atoms), remains a significant challenge. Herein, the microwave-assisted synthesis of copper oxide (CuO) is modulated with ammonium hexafluorophosphate (NH4PF6), obtaining thin CuO (ca. 12nm in thickness) nanosheets with the surface adsorbed with hexafluorophosphate, referred as CuO-PF6. This CuO-PF6 catalyst could help stabilize the key reaction intermediates during CO2ER. Therefore, the Faradaic efficiency (FE) of C2 products (ethylene and ethanol) during CO2ER could be improved to 75.8% ± 0.5% in an H-type electrochemical cell. This C2 FE increases to 82.4% in a flow cell. The improved FE toward C2 species could be attributed to the PF6-modulated electronic structure of Cu surface and stabilization of key reaction intermediates, especially those involving C2 production. In addition, CuO-PF6 also demonstrates a high catalytic stability over 10 h. This work provides a deeper understanding of surface modification strategy for CO2ER enhancement, promising for designing hybrid electrocatalysts with high efficiency and stability for CO2-to-fuel conversion.

Interfacial charge redistribution modulates surface electronic states through Ti-O-Fe bridges: Unlocking dz2-pz orbital hybridization for fast sulfur redox.

ABSTRACT Efficient and cost‐effective electrocatalysts play a crucial role in the alkaline water splitting for H 2 production. In this study, we successfully synthesized a three‐dimensional (3D) sea urchin‐like Ru‐NiCoP self‐supporting electrocatalyst deposited on nickel foam which exhibits good electrocatalytic performance in water splitting. In 1 M KOH aqueous solution, only the low overpotentials of 79.5 mV and 225.2 mV are required to achieve the current density of 10 mA·cm −2 for the hydrogen evolution reaction and oxygen evolution reaction, respectively. For overall water splitting (OWS), a cell voltage of only 1.52 V is needed to generate the current density of 10 mA·cm −2 . Furthermore, the electrode shows long‐term stability for OWS, maintaining its performance for 80 h even at a high current density of 50 mA·cm −2 . The good electrocatalytic performance can be ascribed to the unique 3D sea urchin‐like nanostructure and the synergistic effect of multiple transition metal phosphides in regulating the surface electronic structure. This work provides ideas for developing new precious‐metal‐saving self‐supporting electrodes.

Engineering the surface electronic structure of Pd via Bi alloying and N-doped carbon support for enhanced ethanol oxidation