Constructing a built-in electric field by anchoring highly dispersed Zn single atoms on UiO-66-NH2 for efficient CO2 photoreduction

Abstract

Solar-driven carbon dioxide (CO₂) reduction into valuable chemicals or feedstock is of great significance for the sustainable development of the environment and energy. Herein, we presented a photo-induced reduction method to synthesize catalysts by anchoring Zn single atoms (SAs) on UiO-66-NH₂. Impressively, UiO-66-NH₂-0.7Zn SAs had excellent performance in converting CO₂ to carbon monoxide (CO), which was about a 5-fold improvement compared to pristine UiO-66-NH₂ without a photosensitizer or hole sacrificial agent under UV-vis light. The remarkable photocatalytic CO₂ reduction performance was attributed to the built-in electric field construction by anchoring highly dispersed Zn SAs on UiO-66-NH₂. The built-in electric field could effectively promote the separation of photogenerated charges and activate CO₂. Density functional theory (DFT) calculations revealed that low-coordination Zn–N₂ sites could dramatically enhance the formation of COOH*, which was the rate-limiting step for CO generation. This study created a new opportunity to develop high-efficiency photocatalysts containing single-atom sites for photocatalytic CO₂ reduction.