Visible-light-driven solvent-free photocatalytic CO2 reduction to CO by Co-MOF/Cu2O heterojunction with superior selectivity

[Display omitted] •A novel Co-MOF/Cu2O hybrid composite (xCMC) with p-n heterojunction was achieved.•The composite exhibited enhanced photocatalytic reduction of CO2 with superior selectivity to CO at the gas-solid interface.•The strong light absorption capacity, high surface area and p-n heterojunction enhanced the photocatalytic performance.•The reduction of CO2 was carried out without any photosensitizer, and sacrificing reagent. It is highly desirable to discover MOFs matrix composites with controlled reduction selectivity in the general understanding of the CO2 reduction reaction (CO2RR) in electro- and photocatalytic process. Herein, we demonstrate a facile strategy to prepare metal organic framework hybrid composites (xCMC) using the Co-based MOF [Co2(TMTA)(HCOO)(bidb)(H2O)]∙DMF (H3TMTA = 1,3,5-trimethyl-2,4,6- tricarboxyl- phenylbenzene, bidb = 1,4-bis(1-imidazoly)benzene) and nanocrystalline cuprous oxide. The resulting hybrid catalyst with p-n heterojunction exhibited enhanced photocatalytic CO2 reduction activity with remarkable CO production rate of 3.83 μmol g−1h−1, ca. 9.6 times higher than that of pure Cu2O. Compared with other reaction routes, the present photocatalytic reduction of CO2 with superior selectivity to CO occurs in the interface of solid–gas reaction without the use of photosensitizers or sacrificing reagents. In addition, the mechanism for photocatalytic CO2 reduction was also well discussed. The present work provides unique insight into constructing MOF-based photocatalysts with heterojunction for visible-light-driven CO2 reduction under solid–gas reaction conditions.