Electrochemical coupling nitrate-to-ammonia (NO-to-NH) with urea oxidation reaction (UOR) is attractive for both energy-saving ammonia synthesis and comprehensive nitrogen-rich wastewater treatment. However, developing the efficient electrocatalyst that simultaneously promotes hydrogenation of NO and UOR is still challenging. Here, we engineered the porous CoMoO nanosheets with rich low-valent Mo sites (Mo-CoMoO) as a difunctional electrocatalyst for both NO-to-NH and UOR. The Mo-CoMoO displayed high Faradaic efficiency (93.33%) and selectivity (91.16%) for NO-to-NH and low potential (1.31 V vs. RHE) at 100 mA cm toward UOR. Impressively, a low cell voltage of 1.83 V was needed for coupling UOR with NO-to-NH in two-electrode system. Mechanism study revealed that the introduction of low-valent Mo sites in CoMoO nanosheets accelerated the activation kinetics and multistep hydrogenation of NO, and also promoted the reconstruction of active CoOOH species for UOR, resulting the difunctional catalytic property for NO-to-NH and UOR.

中文翻译：

---

在 CoMoO4 纳米片中设计低价钼位点以促进电化学富氮废水处理


电化学耦合硝酸盐制氨（NO-to-NH）与尿素氧化反应（UOR）对于节能氨合成和综合富氮废水处理都具有吸引力。然而，开发同时促进NO和UOR加氢的高效电催化剂仍然具有挑战性。在这里，我们设计了具有丰富低价 Mo 位点的多孔 CoMoO 纳米片 (Mo-CoMoO) 作为 NO-to-NH 和 UOR 的双功能电催化剂。 Mo-CoMoO2 对 NO 转化为 NH 表现出高法拉第效率 (93.33%) 和选择性 (91.16%)，并且在 100mAcm 下对 UOR 表现出低电势（1.31V vs. RHE）。令人印象深刻的是，在双电极系统中将 UOR 与 NO-to-NH 偶联需要 1.83V 的低电池电压。机理研究表明，在CoMoO纳米片中引入低价Mo位点加速了NO的活化动力学和多步加氢，并促进了UOR活性CoOOH物种的重构，从而产生了NO-to-NH和UOR的双功能催化性能。