Integration of zirconium-based metal–organic framework with CdS for enhanced photocatalytic conversion of CO2 to CO

It is a promising strategy to prepare composite photocatalysts based on MOFs and semiconductors for enhancing photocatalytic reduction of carbon dioxide (CO₂). A family of binary composite photocatalysts (CdS@UiO-66-NH₂) with different CdS contents have been designed and synthesized, which have been explored for photocatalytic reduction of CO₂. CdS@UiO-66-NH₂ can efficiently convert CO₂ into CO under visible light irradiation via the solid-gas mode in the absence of sacrificial agents and photosensitizers. The generation rate of CO can reach up to 280.5 μmol g^-1 h^-1, which is 2.13-fold and 2.9-fold improvements over the pristine CdS and UiO-66-NH₂, respectively, and the selectivity for CO is very high. Furthermore, this kind of photocatalysts can still maintain great photocatalytic activity in CO₂/N₂ mixed atmosphere with different CO₂ concentrations. The outstanding performances of CdS@UiO-66-NH₂ may be attributed to the existence of the direct Z-scheme heterojunction, which possesses the enhanced separation and migration of photo-generated charge carriers between UiO-66-NH₂ and CdS, available specific surface areas and improved visible light absorption ability as well as abundant reaction active sites. This case reveals that MOF-based composite photocatalysts exhibit promising potential applications in the field of CO₂ conversion.