Nitrate (NO3-) and hydrazine (N2H4) are common nitrogen pollutants in groundwater. The electrochemical method can be used to synthesize the added product urea while treating N-pollution. Therefore, the development of sufficiently efficient electrosynthesis urea systems and efficient electrocatalysts is of great significance, but also challenging. In this paper, CuNi alloy nanosheets (CuxNiy /CF) on copper foam surface were synthesized by electrodeposition, and C-N coupled hydrazine oxidation (HzOR) system was constructed by proton exchange membrane (PEM). Cu and Ni in CuNi alloy act as double active sites and react with C-N coupling reaction and HzOR respectively. At −0.5 V potential, the Faraday efficiency of Cu8Ni2/CF for C-N coupling reaction is 51.66 %, and the urea yield is 254.09 μg h−1 cm−2. At the same time, HzOR with low thermodynamic oxidation potential can quickly produce excess H+ to supply protons to the cathode for C-N coupling reaction, thus significantly promoting the forward C-N coupling reaction. Cu1Ni9/CF also showed significant activity in the oxidation reaction of N2H4 in KOH electrolyte. Therefore, we assembled a Cu1Ni9(+) || Cu8Ni2(-) electrolytic cell, which only needs 0.23 V working voltage up to 150 mA cm−2, and can convert NO3- and CO2 to urea at a power consumption of 5.09 kWh kg−1 while converting N2H4. Energy saving 37.6 % compared to conventional C-N coupled OER electrolytic system (about 8.16 kWh kg−1 urea). It can greatly reduce the cost of urea production, make the price of fertilizer and chemical raw materials more competitive, and promote the development of agriculture and chemical industry while reducing greenhouse gas emissions and nitrogen pollutants in the ecological environment. This study reports a promising and effective strategy for the synthesis of urea and treatment of N contaminants at a small operating voltage.

中文翻译：

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用于肼氧化的 CuNi 合金通过质子交换膜辅助节能尿素生产


硝酸盐 （NO3-） 和肼 （N2H4） 是地下水中常见的氮污染物。电化学法可用于在处理 N 污染的同时合成添加的产物尿素。因此，开发足够高效的电合成尿素系统和高效的电催化剂具有重要意义，但也具有挑战性。本文通过电沉积法合成了泡沫铜表面的 CuNi 合金纳米片 （CuxNiy /CF），并通过质子交换膜 （PEM） 构建了 C-N 耦合肼氧化 （HzOR） 系统。CuNi 合金中的 Cu 和 Ni 充当双活性位点，分别与 C-N 耦合反应和 HzOR 反应。在 −0.5 V 电位下，Cu8Ni2/CF 对 C-N 偶联反应的法拉第效率为 51.66 %，尿素产率为 254.09 μg h-1 cm-2。同时，具有低热力学氧化电位的 HzOR 可以迅速产生过量的 H+，为阴极提供质子进行 C-N 耦合反应，从而显着促进正向 C-N 耦合反应。Cu1Ni9/CF 在 KOH 电解液中 N2H4 的氧化反应中也显示出显着的活性。因此，我们组装了一个 Cu1Ni9（+） ||Cu8Ni2（-） 电解槽，只需要 0.23 V 的工作电压，高达 150 mA cm-2，并且可以在转换 N2H4 的同时以 5.09 kWh kg-1 的功耗将 NO3- 和 CO2 转化为尿素。与传统的 C-N 耦合 OER 电解系统（约 8.16 kWh kg-1 尿素）相比，节能 37.6%。它可以大大降低尿素生产成本，使肥料和化工原料的价格更具竞争力，在减少温室气体排放和生态环境中的氮污染物的同时，促进农业和化学工业的发展。 本研究报告了一种在小工作电压下合成尿素和处理 N 污染物的有前途且有效的策略。