Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control, Department of Environmental Science and Engineering, North China Electric Power University, Baoding 071003, PR China.
MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China.
Environ Sci Technol. 2024 Mar 26;58(12):5557-5566. doi: 10.1021/acs.est.3c09811. Epub 2024 Feb 27.
Wet flue gas denitrification offers a new route to convert industrial nitrogen oxides (NO) into highly concentrated nitrate wastewater, from which the nitrogen resource can be recovered to ammonia (NH) via electrochemical nitrate reduction reactions (NITRRs). Low-cost, scalable, and efficient cathodic materials need to be developed to enhance the NH production rate. Here, electrodeposition was adopted to fabricate a foamy Cu-based heterojunction electrode containing both Cu-defects and oxygen vacancy loaded CuO (OVs-CuO), which achieved an NH yield rate of 3.59 mmol h cm, NH Faradaic efficiency of 99.5%, and NH selectivity of 100%. Characterizations and theoretical calculations unveiled that the Cu-defects and OVs-CuO heterojunction boosted the H* yield, suppressed the hydrogen evolution reaction (HER), and served as dual reaction sites to coherently match the tandem reactions kinetics of NO-to-NO and NO-to-NH. An integrated system was further built to combine wet flue gas denitrification and desulfurization, simultaneously converting NO and SO to produce the (NH)SO fertilizer. This study offers new insights into the application of low-cost Cu-based cathode for electrochemically driven wet denitrification wastewater valorization.
湿烟气脱硝为将工业氮氧化物（NO）转化为高浓度硝酸盐废水提供了一条新途径，可通过电化学硝酸盐还原反应（NITRRs）从废水中回收氮资源转化为氨（NH）。需要开发低成本、可扩展且高效的阴极材料来提高 NH 生成速率。在这里，采用电沉积法制备了一种含有 Cu 缺陷和负载氧空位的 CuO（OVs-CuO）的泡沫状 Cu 基异质结电极，实现了 3.59 mmol h cm 的 NH 产率、99.5%的 NH 法拉第效率和 100%的 NH 选择性。通过表征和理论计算揭示，Cu 缺陷和 OVs-CuO 异质结促进了 H*的生成，抑制了析氢反应（HER），并作为双反应位点，协同匹配 NO 到 NO 和 NO 到 NH 的串联反应动力学。进一步构建了一个集成系统，结合湿法烟气脱硫和脱硝，同时将 NO 和 SO 转化为（NH）SO 肥料。该研究为电化学驱动的湿脱硝废水增值利用提供了低成本 Cu 基阴极的应用提供了新的思路。
