Direct Four-Electron Reduction of O2 to H2O on TiO2 Surfaces by Pendant Proton Relay

摘要

TiO2-based photocatalytic aerobic oxidations are among the most promising methods in energy conversion, environmental remediation, and organic transformation by using solar energy. In the photocatalytic reactions, oxygen acts as the ultimate oxidant by scavenging conduction-band electrons, and the oxygen reduction reaction (ORR) carried out by conduction band electrons is the key step, even the rate-determining step, of the overall reactions. During ORR, various reactive oxygen species (i.e. ~·OH, H2O2, O2~(·-)) are generated which are able to strongly influence the reaction mechanisms and product distribution. For example, in our previous study, the ~·OH derived from the H2O2 intermediates of ORR can contribute much to the hydroxylation of aromatics.