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.
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