Highly Selective N2 Electroreduction to NH3 Using a Boron-Vacancy-Rich Diatomic NbB Catalyst.

The ambient electrochemical N 2 reduction reaction (NRR) is a future approach for the artificial NH 3 synthesis to overcome the problems of high-energy consumption and environmental pollution by Haber-Bosch technology. However, the challenge of N 2 activation on a catalyst surface and the competitive hydrogen evolution reaction make the current NRR unsatisfied. Herein, this work demonstrates that NbB 2 nanoflakes (NFs) exhibit excellent selectivity and durability in NRR, which produces NH 3 with a production rate of 30.5 µg h -1 mg cat -1 and a super-high Faraday efficiency (FE) of 40.2%. The high-selective NH 3 production is attributed to the large amount of active B vacancies on the surface of NbB 2 NFs. Density functional theory calculations suggest that the multiple atomic adsorption of N 2 on both unsaturated Nb and B atoms results in a significantly stretched N 2 molecule. The weakened NN triple bonds are easier to be broken for a biased NH 3 production. The diatomic catalysis is a future approach for NRR as it shows a special N 2 adsorption mode that can be well engineered.