Greatly Facilitated Two-Electron Electroreduction of Oxygen into Hydrogen Peroxide over TiO by Mn Doping.

Ambient electrochemical oxygen reduction into valuable hydrogen peroxide (HO) via a selective two-electron (2e) pathway is regarded as a sustainable alternative to the industrial anthraquinone process, but it requires advanced electrocatalysts with high activity and selectivity. In this study, we report that Mn-doped TiO behaves as an efficient electrocatalyst toward highly selective HO synthesis. This catalyst exhibits markedly enhanced 2e oxygen reduction reaction performance with a low onset potential of 0.78 V and a high HO selectivity of 92.7%, much superior to the pristine TiO (0.64 V, 62.2%). Additionally, it demonstrates a much improved HO yield of up to 205 ppm h with good stability during bulk electrolysis in an H-cell device. The significantly boosted catalytic performance is ascribed to the lattice distortion of Mn-doped TiO with a large amount of oxygen vacancies and Ti. Density functional theory calculations reveal that Mn dopant improves the electrical conductivity and reduces Δ of pristine TiO, thus giving rise to a highly efficient HO production process.