Doping strain induced bi-Ti(3+) pairs for efficient N(2) activation and electrocatalytic fixation

The electrochemical N(2) fixation to produce ammonia is attractive but significantly challenging with low yield and poor selectivity. Herein, we first used density function theory calculations to reveal adjacent bi-Ti(3+) pairs formed on anatase TiO(2) as the most active electrocatalytic centers for efficient N(2) lying-down chemisorption and activation. Then, by doping of anatase TiO(2) with Zr(4+) that has similar d-electron configuration and oxide structure but relatively larger ionic size, the adjacent bi-Ti(3+) sites were induced and enriched via a strained effect, which in turn enhanced the formation of oxygen vacancies. The Zr(4+)-doped anatase TiO(2) exhibited excellent electrocatalytic N(2) fixation performances, with an ammonia production rate (8.90 µg·h(−1)·cm(−2)) and a Faradaic efficiency of 17.3% at −0.45 V versus reversible hydrogen electrode under ambient aqueous conditions. Moreover, our work suggests a viewpoint to understand and apply the same-valance dopants in heterogeneous catalysis, which is generally useful but still poorly understood.