Synergistic interaction between g-C3N4 and Cu-Zn-MOFs via electrostatic assembly for enhanced electrocatalytic CO2 reduction

Electrocatalytic carbon dioxide reduction (eCO2R) represents a sustainable technique for converting CO2 into valuable chemicals and fuels. Metal-organic frameworks (MOFs) are recognized as promising candidates in eCO2R due to their favorable adsorption of CO2. However, the insufficiency of adequate active sites restricts their in-depth investigation. Herein, inspired by the interfacial electronic effects, the layered g-C3N4 with unpaired electron characteristics is integrated into Cu-Zn-MOFs with nucleophilic imidazolate ligands via electrostatic assembly. The resultant g-C3N4@Cu-Zn-MOFs-1 : 1 exhibits excellent CO2 reduction performance for CO in a wide potential range, where the peak faradaic efficiency reaches 85% at -1.3 V. g-C3N4 with a graphitic carbon backbone significantly stabilizes the Cu-Zn-MOF structure and enhances the exposure of active sites. The excellent performance stems from the significant activation of active sites by the efficient electron transfer induced by π-π stacking interactions between g-C3N4 and Cu-Zn-MOFs-1 : 1. This work proposes an innovative approach to stabilizing MOFs and activating the active sites in MOFs through interfacial electron engineering for CO2 reduction.