The electrocatalytic N₂ reduction reaction (NRR) to produce ammonia is an attractive but highly challenging approach, due to the extreme inertness of N₂ molecules and significantly lower N₂ concentration compared to the surrounding water molecules. Herein, NbO₂ nanoparticles are demonstrated as an efficient NRR electrocatalyst with significantly improved electrochemical performances. Compared to Nb₂O₅ with a similar crystal structure unit but different linkage, the Nb⁴⁺ cation not only provides empty d‐orbitals for strong N₂ adsorption, but also a single d‐electron to further enable back donation to activate the NN triple bond. As a result, the NbO₂ nanoparticles present an outstanding ammonia production rate of 11.6 µg h⁻¹ mg_cat.⁻¹ at −0.65 V versus reversible hydrogen electrode (RHE) and an excellent electrochemical stability, significantly higher than those of the Nb₂O₅ nanorods under similar conditions. More importantly, a peak faradaic efficiency of ammonia production of 32% is obtained for NbO₂ at −0.60 V versus RHE, which is one of the highest reported NRR faradaic efficiencies to date.

中文翻译：

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NbO2电催化剂对N2固定的法拉第效率达到32％

产生氨的电催化N ₂还原反应（NRR）是一种有吸引力但极具挑战性的方法，因为N ₂分子的惰性极强，并且与周围的水分子相比N _2的浓度明显降低。在本文中，NbO ₂纳米颗粒被证明是一种有效的NRR电催化剂，具有显着改善的电化学性能。与具有相似晶体结构但键合不同的Nb ₂ O ₅相比，Nb ⁴⁺阳离子不仅为强N ₂提供了空的d轨道。吸附，而且还有一个d电子，以进一步使背电荷激活NN三键。结果，NbO ₂纳米颗粒的氨生产率达到了11.6 µg h ^-1 mg _cat。与可逆氢电极（RHE）相比，在-0.65 V时为^-1，并且电化学稳定性极好，在相似条件下明显高于Nb ₂ O ₅纳米棒。更重要的是，相对于RHE，NbO ₂在-0.60 V时氨的法拉第效率峰值达到32％，这是迄今为止报道的最高NRR法拉第效率之一。