铜镍纳米结构修饰多孔电极的电化学硝酸根还原

利用电化学将硝酸根转化为有价值的氨是硝酸盐处置绿色、低碳的途径。本研究制备了铜镍纳米结构修饰多孔电极(Ni-Cu NW)，同时构建了电场与流场相协同的穿透式电化学反应器体系。在施加-0.6 V (vs. RHE)电位条件下，该体系氨法拉第效率可达到(84.35±3.63)%，而泡沫Cu电极的法拉第效率仅为(17.2±0.63)%。在定制的穿透式反应器中，Ni-Cu NW电极在−0.6 V、300 r·min⁻¹转速条件下对1 400 mg·L⁻¹ NO₃^--N 溶液电解，100 min后硝酸盐的转化率接近100%，氨选择性为85.5%。电子自旋共振能谱(ESR)和H_ads淬灭实验证明除了电极直接还原硝酸盐，体系中的H_ads可帮助进一步还原硝酸盐。以50 mA·cm⁻²恒电流密度运行24 h，运行前后电极的硝酸盐还原性能未产生明显变化。

Electrochemical nitrate reduction of porous electrodes modified with Ni-Cu nanostructures

Electrochemical conversion of nitrate ions into valuable ammonia is a green and low carbon approach for nitrate disposal. A porous electrode modified with Ni-Cu nanostructure was prepared and the according flow-through electrochemical reactor system was constructed with the synergy of electric field and flow field. At −0.6V(vs. RHE), the Faraday efficiency of ammonia reached (84.35±3.63)%, whereas that of foam Cu electrode was only (17.2±0.63)%. By using the flow-through reactor, the Ni-Cu NW electrode electrolyzed 1 400 mg·L−1 NO3--N at the potential of −0.6 V, a stirring rate of 300 r·min−1, After 100 min treatment, the results exhibited that the conversion rate of nitrate and the selectivity of ammonia was 100% and 85.5%, respectively. Electron spin resonance spectroscopy (ESR) and Hads quenching experiments showed that in addition to direct reduction of nitrate by electrode, the produced Hads could further facilitate nitrate reduction. With a current of 50 mA·cm−2 for 24 hours, no obvious change in nitrate reduction performance could occur before and after running.