Electrocatalytic conversion of carbon dioxide (CO2) into formate offers a sustainable pathway to mitigate environmental degradation and the energy crisis. Tin (Sn)-based materials are promising electrocatalysts for CO2 reduction to formate; however, their efficiency is limited by weak CO2 adsorption and activation, as well as sluggish reaction kinetics. In this work, we designed an intercrossing nanoporous Cu6Sn5/Sn intermetallic heterojunction via a scalable alloying-etching protocol. The resulting Cu6Sn5/Sn catalyst with abundant interfacial sites exhibited enhanced formate selectivity (60.79%) at − 0.93 V versus the reversible hydrogen electrode (RHE), together with a high partial current density of 12.56 mA/cm2 and stable operation for 16 h. The modulated electronic structure of Cu6Sn5 coupled with the robust interfacial interaction between Sn and Cu6Sn5 synergistically promoted CO2 adsorption and activation, thereby improving CO2 reduction reaction (CO2RR) performance. Electrochemical measurements and in situ infrared spectroscopy confirmed that the dual-phase interfaces facilitate H2O decomposition and the generation of abundant *H intermediates, which in turn accelerate the protonation of CO2 to formate. This work highlights a scalable strategy for constructing intermetallic heterojunction catalysts that combine facile synthesis, reproducibility, and superior catalytic activity for CO2RR.
The development of efficient photocatalysts for selective organic transformations under visible light remains a major challenge in sustainable chemistry. In this study, we present a straightforward solvothermal strategy for fabricating a defect-engineered ZrO2/UiO-66-NH2 hybrid material with abundant oxygen vacancies, enabling the visible-light-driven oxidation of benzyl alcohol to benzaldehyde. By optimizing the solvothermal treatment duration, the composite (UiO-66-NH2-2 h) achieves a 74.1% conversion of benzyl alcohol with > 99% selectivity toward benzaldehyde under mild conditions, substantially outperforming pristine UiO-66-NH2. Structural and mechanistic studies reveal that the solvothermal process induces the in situ formation of ultrasmall, uniformly dispersed ZrO2 nanoparticles (~ 2.3 nm) within the MOF matrix, while simultaneously generating abundant oxygen vacancies, as confirmed by XPS, EPR, and HRTEM analyses. The defect-mediated electronic structure of the ZrO2/UiO-66-NH2 hybrid enhances visible-light absorption, facilitates charge carrier separation, and promotes efficient activation of O2 into superoxide radicals (·O2−), the primary reactive species. Transient photocurrent measurements and electrochemical impedance spectroscopy further verify the improved charge separation efficiency. The synergistic interplay between oxygen vacancies and the intimate ZrO2/UiO-66-NH2 interface provides a unique defect-mediated charge transfer pathway, distinguishing this system from conventional heterojunctions. This study demonstrates a facile, one-step approach to integrate defect engineering with interfacial hybridization in MOF-based photocatalysts, offering a scalable route for solar-driven organic synthesis.