Highly efficient two-electron electroreduction of oxygen into hydrogen peroxide over Cu-doped TiO2

Electrosynthesis of hydrogen peroxide (H2O2), as a sustainable alternative to the anthraquinone oxidation method, provides the feasibility of directly generating H2O2. Here, we report Cu-doped TiO2 as an efficient electrocatalyst which exhibits the excellent two-electron oxygen reduction reaction (2e− ORR) performance with respect to the pristine TiO2. The Cu doping results in the distortion of TiO2 lattice and further forms a large number of oxygen vacancies and Ti3+. Such Cu-doped TiO2 exhibits a positive onset potential about 0.79 V and high H2O2 selectivity about 91.2%. Moreover, it also shows a larger H2O2 yield and good stability. Density functional theory (DFT) calculations reveal that Cu dopant not only improves the electrical conductivity of pristine TiO2 but reduces the *OOH adsorption energy of active sites, which is beneficial to promote subsequently 2e− ORR process.