Modulating Oxygen Vacancies of TiO₂ Nanospheres by Mn-Doping to Boost Electrocatalytic N₂ Reduction

Electrochemical N2 reduction reaction (NRR) is an environmentally benign and sustainable approach for NH3 synthesis under ambient conditions, which needs efficient electrocatalyst to meet the enormous challenge of activating the inert N2 molecule. Recently, TiO2 emerges as an active NRR electrocatalyst with advantages of abundance, nontoxicity, and high thermal stability. Heteroatom doping is an effective oxygen vacancy introduction strategy to manufacture unique electron and structure properties of metal oxides, which will greatly influence the catalysts’ activity. In this work, we developed Mn-doped TiO2 nanospheres (Mn-TiO2) for electrochemical NRR. In 0.1 M Na2SO4, Mn-TiO2 shows a large NH3 yield rate of 20.05 μg h–1 mgcat.–1 and a high Faradaic efficiency of 11.93%, which are much higher than undoped TiO2. The mechanism of performance improvement is uncovered by density functional theory calculations.