Reticular copper dual sites embedded with semiconductor particles for selective CO2-to-C2H4 photoreduction

Abstract

Dual sites, positioned through atomically precise proximity coordination for C–C coupling, serve as an exemplary platform for CO₂-to-C₂H₄ conversion. Nonetheless, their surface-only distribution results in inefficient photogenerated electron injection via long-range migration from the bulk phase, leading to inadequate site charge to drive the consecutive electron transfers for C₂H₄ synthesis. Here we demonstrate a reticular dual-site photocatalyst design by embedding semiconductor units (TiO₂, polymeric carbon nitride or WO₃·H₂O) within ligand-defective copper-based metal–organic frameworks (CuBTC-D/PC). This system demonstrates a 75.5% selectivity in converting CO₂ to C₂H₄ with H₂O as the electron donor. The reticular copper dual sites facilitate short-range photogenerated electron transfer from the photocatalyst to active sites, ensuring a sufficient electron concentration for all elementary steps in C₂H₄ conversion. Enhanced electron injection allows for high C₂H₄ selectivity even under low-intensity irradiation (~0.4 Sun), demonstrating suitability for solar-driven applications. This work establishes the feasibility of CO₂ photoreduction to C₂H₄ as a primary product, providing insights into multi-electron CO₂ photoreduction.