Dual MOFs template-directed fabrication of hollow-structured heterojunction photocatalysts for efficient CO2 reduction

Developing efficient photocatalysts for CO2 reduction into value-added chemical feedstocks is of significance. Heterojunction photocatalysts are promising candidates but still suffering from the insufficient electron-hole pair separation issues. Herein, a strategy that dual metal–organic frameworks (MOFs) template-directed fabrication of carbon-supported heterojunction, C-In2O3@MO (MO = ZnO, Co3O4, and ZnCo2O4) with tunable band matching structure was developed. The resultant hollow- structured C-In2O3@ZnCo2O4 shows high CO2 reduction activity towards CO (44.1 μmol g1 h−1) with a selectivity of 66%. The superior performance of this material could be ascribed to the suitable energy band matching and efficient internal charge transfer on p-n heterojunction, which facilitates electron-hole separation. Meanwhile, the hollow cavity not only improved light-harvesting capability through multiple light reflection and scattering in the internal voids but also provided large surface area for exposing active sites to promoting the activation of CO2. This study thus proposes a feasible approach to adjust the heterojunction structure of photocatalysts to achieve efficient CO2 reduction reaction.