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

Abstract

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.