MOF-derived ZnO/nGNC catalyst with electron-rich active center for highly efficient CO2 electroreduction to CO

Adsorption and activation of CO2 are among the most intractable challenges of electrochemical CO2 reduction reaction (CO2RR). Various metal-organic frameworks (MOFs), such as Calgary Framework 20 (CALF-20), have demonstrated superior CO2 adsorption capabilities. However, given the exceptional stability of CO2 molecules and the significant challenge in breaking their chemical bonds, there is a pressing need to develop electrocatalysts that can effectively activate CO2. Herein, we explored a MOF pyrolysis modification strategy that utilizes the electronic properties of different functional ligands to promote CO2 activation. The derivatives of Zn-based MOFs with three ligands, namely 1,2,4-triazole in CALF20, 2-methylimidazole in zeolitic imidazolate framework-8 (ZIF-8) and 2,5-dihydroxyterephthalic acid in Zn-MOF-74, were studied in an H-type cell. CALF-20-derived ZnO/nGNC was proved to be an efficient electrocatalyst towards CO2 reduction with high selectivity to CO. After pyrolysis, electrons are transferred from carbon to metal, resulting in electron-rich active center Zn, effectively activating CO2 and accelerating the reaction kinetics, thus leading to a superior performance. The result show that ZnO/nGNC exhibited a high Faradaic efficiency (FE) in the -0.85 similar to -1.15 V vs RHE (maximum of 87.3 +/- 0.6 %). This study gives a practical idea for the synthesis of electrocatalysts with electron-rich active centers.