Abstract
Electrochemical nitrate reduction reaction(NITRR)is regarded as a"two birds-one stone"method for the treatment of nitrate contaminant in polluted water and the synthesis of valuable ammonia,which is re-tarded by the lack of highly reactive and selective electrocatalysts.Herein,for the first time,nickel foam supported Co4N was designed as a high-performance NITRR catalyst by an in-situ nonmetal leaching-induced strategy.At the optimal potential,the Co4N/NF catalyst achieves ultra-high Faraday efficiency and NH3 selectivity of 95.4％and 99.4％,respectively.Ex situ X-ray absorption spectroscopy(XAS),together with other experiments powerfully reveal that the nitrogen vacancies produced by nitrogen leaching are stable and play a key role in boosting nitrate reduction to ammonia.Theoretical calculations confirm that Co4N with abundant nitrogen vacancies can optimize the adsorption energies of NO3-and intermediates,lower the free energy(ΔG)of the potential-determining step(*NH3 to NH3)and inhibit the formation of N-containing byproducts.In addition,we also conclude that the nitrogen vacancies can stabilize the adsorbed hydrogen,making H2 quite difficult to produce,and lowering ΔG from*NO to*NOH,which facilitates the selective reduction of nitrate.This study reveals significant insights about the in-situ non-metal leaching to enhance the NITRR activity.
基金项目
国家自然科学基金(91741105)
国家自然科学基金(22006120)
重庆市高等学校创新团队建设计划(CXTDX201601011)
Chongqing Municipal Natural Science Foundation(cstc2018jcyjAX0625)
维普
万方数据