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.