Oxygen vacancy associated single-electron transfer for photofixation of CO 2 to long-chain chemicals

Abstract

The photofixation and utilization of CO 2 via single-electron mechanism is considered to be a clean and green way to produce high-value-added commodity chemicals with long carbon chains. However, this topic has not been fully explored for the highly negative reduction potential in the formation of reactive carbonate radical. Herein, by taking Bi 2 O 3 nanosheets as a model system, we illustrate that oxygen vacancies confined in atomic layers can lower the adsorption energy of CO 2 on the reactive sites, and thus activate CO 2 by single-electron transfer in mild conditions. As demonstrated, Bi 2 O 3 nanosheets with rich oxygen vacancies show enhanced generation of •CO 2– species during the reaction process and achieve a high conversion yield of dimethyl carbonate (DMC) with nearly 100% selectivity in the presence of methanol. This study establishes a practical way for the photofixation of CO 2 to long-chain chemicals via defect engineering.