Oxygen vacancy associated single-electron transfer for photofixation of CO2 to long-chain chemicals

The photofixation and utilization of CO₂ 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 Bi₂O₃ nanosheets as a model system, we illustrate that oxygen vacancies confined in atomic layers can lower the adsorption energy of CO₂ on the reactive sites, and thus activate CO₂ by single-electron transfer in mild conditions. As demonstrated, Bi₂O₃ nanosheets with rich oxygen vacancies show enhanced generation of •CO₂⁻ 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 CO₂ to long-chain chemicals via defect engineering.