Greatly Facilitated Two-Electron Electroreduction of Oxygen into Hydrogen Peroxide over TiO₂ by Mn Doping

Ambient electrochemical oxygen reduction into valuable hydrogen peroxide (H₂O₂) 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 TiO₂ behaves as an efficient electrocatalyst toward highly selective H₂O₂ synthesis. This catalyst exhibits markedly enhanced 2e^- oxygen reduction reaction performance with a low onset potential of 0.78 V and a high H₂O₂ selectivity of 92.7%, much superior to the pristine TiO₂ (0.64 V, 62.2%). Additionally, it demonstrates a much improved H₂O₂ yield of up to 205 ppm h^-1 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 TiO₂ with a large amount of oxygen vacancies and Ti³⁺. Density functional theory calculations reveal that Mn dopant improves the electrical conductivity and reduces ΔG_*OOH of pristine TiO₂, thus giving rise to a highly efficient H₂O₂ production process.