铜镍纳米结构修饰多孔电极的电化学硝酸根还原

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

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1400 mg·L^(-1)NO_(3)^(-)-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 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) NO_(3)~--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% and85.5%,respectively.Electron spin resonance spectroscopy(ESR) and H_(ads) quenching experiments showed that in addition to direct reduction of nitrate by electrode,the produced H_(ads) 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.