Ti3+ self-doped TiO2−x nanowires for efficient electrocatalytic N2 reduction to NH3

Abstract

Electrochemical N₂ reduction is an environmentally friendly and sustainable approach for NH₃ synthesis under mild conditions, while an efficient electrocatalyst is crucial for the N₂ reduction reaction (NRR). Herein, we report Ti³⁺ self-doped TiO_2−x nanowires on Ti mesh (Ti³⁺–TiO_2−x/TM) as an efficient non-noble-metal NRR electrocatalyst with excellent selectivity. In 0.1 M Na₂SO₄, the Ti³⁺–TiO_2−x/TM achieves a high faradaic efficiency of 14.62% with a NH₃ yield of 3.51 × 10⁻¹¹ mol s⁻¹ cm⁻² at −0.55 V vs. the reversible hydrogen electrode. Density functional theory calculations further reveal that introducing Ti³⁺ decreases the reaction energy barrier and increases the number of active sites on the TiO₂ surface for the NRR.