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

Electrochemical N 2 reduction reaction (NRR) is an environmentally benign and sustainable approach for NH 3 synthesis under ambient conditions, which needs efficient electrocatalyst to meet the enormous challenge of activating the inert N 2 molecule. Recently, TiO 2 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 TiO 2 nanospheres (Mn-TiO 2 ) for electrochemical NRR. In 0.1 M Na 2 SO 4, Mn-TiO 2 shows a large NH 3 yield rate of 20.05 μg h –1 mg cat. –1 and a high Faradaic efficiency of 11.93%, which are much higher than undoped TiO 2 . The mechanism of performance improvement is uncovered by density functional theory calculations.