Architecting Bismuth Molybdate Nanoparticles with Abundant Oxygen Vacancies and High Bismuth Concentration for Efficient N2 Electroreduction to NH3

N2 electroreduction reaction (NRR) enables an eco-friendly NH3 synthesis under mild conditions, which is regarded as a carbon-neutral alternative technology to the traditional Haber–Bosch process. However, its practical applications are seriously impeded by the difficulty in N2 adsorption and activation over catalysts, as well as the competing hydrogen evolution reaction (HER). In this work, a novel bismuth molybdate nanocatalyst with sufficient oxygen vacancies and high Biconcentration (41.9 at%), BiMoO-OVs, is synthesized and demonstrated as an excellent NRR electrocatalyst. Benefiting from synergistic effect of the adequate Bi active centers with inert HER activity provided by the high concentration of Bi, and the reinforced N2 adsorption and activation ability of oxygen vacancies, the as-synthesized BiMoO-OVs presents a high Faradaic efficiency of 16.38% with a NH3 yield rate of 3.65 µg h−1 cm−2 at −0.4 V (vs RHE) in neutral electrolyte, which outperforms those of most Bi-based NRR nanocatalysts. Noticeably, it also presents excellent electrochemical durability for at least 24 h. The present work provides a simple and effective strategy for designing low-cost and high-performance Bi-based catalysts.