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.