Cu₂O@ZIF-8 hybrid catalysts with optimized electronic structures tailored by interfacial interactions for efficient electrocatalytic CO₂ reduction

The electrocatalytic reduction of CO₂ into value-added products is a promising and sustainable strategy to mitigate greenhouse gas emissions while generating valuable chemical feedstocks. However, achieving high selectivity, efficiency, and stability remains a significant challenge. In this work, a hybrid material consisting of zeolite-imidazolate framework-8 (ZIF-8) and Cu₂O is synthesized for efficient electrocatalytic reduction reaction of CO₂ (CO₂RR) into carbon monoxide (CO) and methane (CH₄). The hybrid catalyst combines the high surface area and porous structure of ZIF-8 with the excellent catalytic properties of Cu₂O, yielding exceptional dual-product selectivity. Cu₂O@ZIF-8 achieves a high current density of 40 mA cm⁻² and a remarkable FE_CO of 84.7% at −1.0 V and FE_CH4 of 78.8% at −1.2 V with a large current density of 63.6 mA cm⁻², respectively. The hybrid structure also demonstrates exceptional stability, retaining its activity and morphology over 20 hours of continuous operation. Density Functional Theory (DFT) calculations reveal that the incorporation of Cu₂O reduces the bandgap of ZIF-8 and enhances the electron density of sp² carbon sites, enabling efficient charge transfer and stabilization of key intermediates like COOH*. Moreover, the electron-rich sp² carbon atoms help stabilize the COOH* intermediate after combining Cu₂O with ZIF-8, enhancing the interaction between Zn-N and Cu-N sites. This work provides critical insights into the design of MOF-based hybrid catalysts, offering a simple yet effective approach for advancing CO₂ reduction technologies.