Fabricating MOF@COF core-shell catalyst with remarkable CO2 adsorption capacity and charge carrier dynamic for efficient CO2 conversion

Abstract

In this study, we utilized Zn-atz (MOFs) with a high CO2 adsorption capacity and composite it with COF-TD (COFs) via an imine bond to form Zn-atz@COF-TD. The resulting composite material exhibited a significantly higher CO2 adsorption capacity of reaching 39.0 cm3g−1, which was 2.3 times that of Zn-atz and 9.0 times that of COF-TD. The exceptional CO2 adsorption ability enhanced the concentration of CO2 around the active sites, which is beneficial for CO2 reduction. Moreover, the covalent bonding of Zn-atz to COF-TD through an imine bond provided a pathway for charge carrier transfer, facilitating electron-hole separation and migration. These two advantages synergistically accelerated the conversion of CO2 with high efficiency. Under the optimal reaction conditions, Zn-atz@COF-TD demonstrated a CO evolution rate of 8.94 μmolg−1h−1, which is 4.5 times that of Zn-atz and 2.3 times that of COF-TD. Isotope labeling experiments confirmed that the resulting CO was derived from CO2. Additionally, the photocatalysis reaction process is environmentally friendly as it does not require any sacrificial agent. Based on the results of in situ FT-IR spectra, a proposed reaction pathway of photocatalytic CO2 reduction is presented. This study offers novel insights into the utilization of MOFs@COFs-based materials with a core-shell structure in the field of photocatalysis.