State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
Tongji Advanced Membrane Technology Center, Shanghai 200092, China.
ACS Appl Mater Interfaces. 2022 Dec 7;14(48):53884-53892. doi: 10.1021/acsami.2c16856. Epub 2022 Nov 24.
Electrochemical reduction of nitrate to ammonia is of great interest in water treatment with regard to the conversion of contaminants to value-added products, which requires the development of advanced electrodes to achieve high selectivity, stability, and Faradaic efficiency (FE). Herein, nickel phthalocyanine was homogeneously doped into the fiber of a carbon nanotube (CNT) sponge, enabling the production of an electrode with high electrochemical double-layer capacitance () and a large electrochemically active surface area (ECSA). The as-prepared NiPc-CNT sponge could achieve 97.6% nitrate removal, 88.4% ammonia selectivity, and 86.8% FE at a nitrate concentration of 50 mg-N L under an optimized potential of -1.2 V (vs Ag/AgCl). Meanwhile, the ammonia selectivity could be further improved at the high nitrate concentration. Density functional theory calculations showed that the exposure of Ni-N active sites could effectively suppress the hydrogen evolution reaction and dinitrogen generation, enhancing the ammonia selectivity and Faradaic efficiency. Overall, this work sheds light on the conversion of nitrate to ammonia on the metal phthalocyanine-based electrode, offering a novel strategy for managing nitrate in wastewater.
电化学还原硝酸盐为氨在水处理中具有重要意义，因为它可以将污染物转化为有价值的产品，这需要开发先进的电极来实现高选择性、稳定性和法拉第效率（FE）。在此，将酞菁镍均匀掺杂到碳纳米管（CNT）海绵的纤维中，从而制备出具有高电化学双层电容（）和大电化学活性表面积（ECSA）的电极。在优化的-1.2 V（相对于 Ag/AgCl）电位下，所制备的 NiPc-CNT 海绵在 50 mg-N L 的硝酸盐浓度下可以实现 97.6%的硝酸盐去除率、88.4%的氨选择性和 86.8%的 FE。同时，在高硝酸盐浓度下，氨的选择性可以进一步提高。密度泛函理论计算表明，暴露的 Ni-N 活性位点可以有效地抑制析氢反应和氮气生成，从而提高氨的选择性和法拉第效率。总的来说，这项工作为基于金属酞菁的电极上硝酸盐向氨的转化提供了新的见解，为废水中硝酸盐的管理提供了一种新策略。
