Ag–O–Ce3+ atomic interface and surface oxygen vacancies on CeO2 synergistically promoted the selective visible photocatalytic reduction of carbon dioxide

Abstract

The CO₂ conversion into high-value-added chemicals is highly meaningful. Photocatalysis is a feasible and promising method to realize this transformation, in which photocatalyst plays a key role. Ceria (CeO₂) has attracted extensive attention in the photocatalytic conversion of CO₂. However, the surface oxygen vacancies (V_Os) of CeO₂ are unstable and lead to low reactivity. Herein, we found that the highly dispersed Ag species via coordination method stabilized the V_Os of CeO₂, and the synergy of the Ag species and V_Os played a crucial role in the selective photocatalytic CO₂ conversion. The formed Ag–O–Ce³⁺ atomic interface promoted the electron transfer from Ce³⁺ defective sites to Ag atoms, thereby improving the separation efficiency of the charge carriers, leading to enhanced photocatalytic activity. The V_Os-sufficient CeO₂ had high selectivity for the photocatalytic reduction of CO₂ to methanol, while highly selective acetone was achieved on Ag- V_Os/CeO₂. The synergy of Ag and V_Os that form a frustrated Lewis pair promoted not only the adsorption and activation of CO₂ molecules but also the selectivity of products. The key intermediate species, *COOH and *CH₃, were stably preserved by the synergy of Ag and V_Os. This work provides insight into the selective conversion of CO₂ to high-value-added organics via the surface regulation of photocatalysts.