Developing efficient and low-cost electrocatalysts is essential for the electroreduction of N₂ to NH₃. Here, highly monodispersed MoO₃ clusters loaded on a coral-like CeO_x compound with abundant oxygen vacancies are successfully prepared by an impregnation–reduction method. The MoO₃ clusters with small sizes of 2.6 ± 0.5 nm are induced and anchored by the oxygen vacancies of CeO_x, resulting in excellent nitrogen reduction reaction (NRR) performance. Additionally, the synergistic effects between MoO₃ and CeO_x lead to a further improvement of the electrochemical performance. The as-prepared MoO₃–CeO_x catalyst shows an NH₃ yield rate of 32.2 μg h⁻¹ mg_cat⁻¹ and a faradaic efficiency of 7.04% at −0.75 V (vs. reversible hydrogen electrode) in 0.01 M Dulbecco's Phosphate Buffered Saline. Moreover, it displays decent electrochemical stability over 30,000 s. Besides, the electrochemical NRR mechanism for MoO₃–CeO_x is investigated by in-situ Fourier transform infrared spectroscopy. N–H stretching, H–N–H bending, and N–N stretching are detected during the reaction, suggesting that an associative pathway is followed. This work provides an approach to designing and synthesizing potential electrocatalysts for NRR.

开发高效和低成本的电催化剂对于将N ₂电还原为NH ₃至关重要。在这里，通过浸渍-还原法成功地制备了高度单分散的MoO ₃团簇，其负载在具有丰富氧空位的珊瑚状CeO _x化合物上。CeO _x的氧空位诱导并固定了尺寸为2.6±0.5 nm的MoO ₃团簇，从而实现了出色的氮还原反应（NRR）性能。另外，MoO ₃和CeO _x之间的协同作用导致电化学性能的进一步改善。准备好的MoO ₃ -CeO_x催化剂在0.01 M Dulbecco磷酸盐缓冲盐水中的NH ₃产率为32.2μgh ^-1  mg _cat ^-1，法拉第效率为-0.75 V（相对于可逆氢电极）为7.04％。此外，它在30,000 s内显示出良好的电化学稳定性。此外，通过原位傅里叶变换红外光谱研究了MoO ₃ -CeO _x的电化学NRR机理。在反应过程中检测到N–H拉伸，H–N–H弯曲和N–N拉伸，这表明遵循了缔合途径。这项工作为NRR设计和合成潜在的电催化剂提供了一种方法。