Synergistic effect of Zn2GeO4 nanorod decorated metal organic framework ZIF-67 and its metal ligand charge transfer effect towards the photocatalytic CO2 reduction and C–C coupling

Abstract

Metal-organic framework (MOF) especially zeolitic imidazole framework (ZIF-67) has shown tremendous efficiency in the field of CO2 adsorption, storage, and conversion due to its huge surface area and metal ligand charge transfer effect. A metal organic imidazole framework-based heterojunction, Zn2GeO4/ZIF-67 nanocomposite has been successfully synthesized where Zn2GeO4 nanorod deposited on the surface of high crystalline ZIF-67 to form an electronic Z scheme mechanism. The Zn2GeO4/ZIF-67 nanocomposite containing 20% Zn2GeO4 nanorod exhibit at about 1.62 times higher methanol production (41.16 μmol/g) than pure ZIF-67 (25.39 μmol/g) and the highest ethanol production was 1.53 times higher (32.66 μmol/g) than pure ZIF-67 (21.34 μmol/g) after 8 h of light irradiation. The electronic interaction of ZIF-67 and Zn2GeO4 has been studied theoretically using density functional theory calculation. Molecular orbital transition and excitation states were also calculated using time-dependent density functional theory calculation. The reaction pathway for CO2 reduction was determined by calculating free energy for each charge transfer intermediates.