Enhanced photocatalytic CO2 reduction by controlled oxygen vacancy generation and co-constructed heterojunction strategy for Pd/CeO2†
Abstract
Artificial photoreduction of carbon dioxide (CO2) into useful chemicals using solar energy requires stable photocatalysts with efficient charge separation and effective CO2 adsorption. Herein, the CeO2-supported Pd catalysts (Pd/CeO2-Vo(r)) with rich oxygen vacancies (Vo) are prepared using the thermal reduction method. The formation of heterojunctions between Pd nanoparticles and CeO2 hollow spheres promotes the transfer of photogenerated electrons, and the Vo of CeO2 exhibits an electron capture effect, thus this synergistic effect effectively enhances light absorption and facilitates the separation and transfer of photogenerated electrons. Therefore the Pd/CeO2-Vo(r) exhibits excellent photocatalytic CO2 reduction to CO with a production rate of 210.9 μmol h−1 g−1, which is more competitive than most of the reported photocatalysts. In situ FTIR is used to further reveal the photocatalytic mechanism of CO2, proving that the key intermediates COOH* and CO* are formed during the photoreduction process. This innovation provides a convenient method for designing photocatalysts with significant CO2 capture capacity, which could provide novel insights into the photocatalytic reduction of CO2.