Oriented Growth of In Situ Coordinated MOF on Spherical Cu₂O for Electrocatalytic CO₂ Reduction to Ethanol

The electrocatalytic carbon dioxide reduction reaction (CO₂RR) offers a promising approach for the conversion of carbon dioxide into valuable C₂ chemicals and fuels. Nevertheless, challenges persist in attaining high selectivity, stability, and yield. Dual-phase copper-based catalysts, particularly cuprous oxide (Cu₂O), exhibit potential owing to their favorable carbon monoxide adsorption and carbon-carbon (C-C) coupling capabilities. However, they encounter problems such as structural instability, agglomeration, and insufficient Faradaic efficiency (FE) for C₂ products. This study addresses these limitations by proposing an innovative strategy for the oriented growth of in situ coordinated metal-organic framework (MOF) shells on spherical Cu₂O. Through the control of ligand density on the Cu₂O surface, a Cu₂O@Cu-BTC composite catalyst was synthesized, integrating the advantages of Cu₂O and MOFs. The MOF shell not only stabilizes the Cu₂O core against agglomeration, but also creates a Cu(I)-O coordination microenvironment that enhances C-C coupling efficiency. Electrochemical evaluations reveal exceptional performance. The low-coordination copper sites at the Cu₂O@Cu-BTC-0.5 interface achieve a high FE of 58.5% for ethanol (C₂H₅OH) production, along with a yield of 454.73 μmol cm^-2 in neutral media, and improved structural durability. This work emphasizes the crucial role of tailored coordination environments in MOF-based composite catalysts for optimizing CO₂RR pathways, presenting a feasible strategy to promote the scalable production of C₂ products with high selectivity and stability.