MOFs-derived ultrathin holey Co3O4 nanosheets for enhanced visible light CO2 reduction

Reducing carbon dioxide (CO 2 ) to various value-added chemical products by photocatalysis could effectively alleviate the serious problems of global warming and energy shortages. Currently, most commonly prepared photocatalysts present poor performance under visible light irradiation. In this study, we adopted a facile, scalable and controllable approach to prepare ultrathin two-dimensional (2D) porous Co 3 O 4 catalysts (Co 3 O 4 -NS) by air calcining of the ultrathin metal-organic framework (MOFs) nanosheet templates to validly reduce CO 2 with a Ru-based photosensitizer under visible light irradiation. Benefitting from the structural nature of MOFs precursors, the calcined Co 3 O 4 -NS inherit the morphology of 2D and well-developed porosity, which support the transport of electrons, enhance the adsorption of CO 2 molecules, and render abundant catalytic sites for CO 2 activation. As a result, the CO generation rate is approximately 4.52 μmol·h −1 with selectivity of 70.1%, which is superior to the Co 3 O 4 bulk catalysts (Co 3 O 4 -BK). Additionally, density functional theory (DFT) calculations reveal that the model of Co 3 O 4 monolayer has stronger CO 2 adsorption energy than that of the Co 3 O 4 bulk, which is beneficial for the CO 2 -to-CO conversion. This MOF-engaged strategy provides new insight into the controlled synthesis of advanced ultrathin holey nanosheets to improve the efficiency of photocatalytic CO 2 reduction.