Wang Xiaoxiong, Winter Lea R, Wu Xuanhao, Fan Yingzheng, Zhao Yumeng, Kim Jae-Hong, Elimelech Menachem
Institute for Ocean Engineering & Center of Double Helix, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06520, USA.
Sci Adv. 2025 Jul 11;11(28):eads6943. doi: 10.1126/sciadv.ads6943. Epub 2025 Jul 9.
Conventional electrochemical reactors for nitrate reduction typically suffer from limited reaction efficiency when applied for real-world water treatment due to poor utilization of electrocatalytic active sites. Here, we applied nanoporous electrofiltration to intensify atomic utilization by incorporating single-atom catalysts into an electrified membrane for reducing low-concentration nitrate to ammonia under realistic water conditions. We enhance the exposure of single atoms in nanopores by coating the catalysts on a carbon nanotube-interwoven membrane framework. Electrofiltration intensifies the transport and adsorption of nitrate in confined nanopores with highly exposed single-atom active sites to enhance reduction. The membrane enables a superior ammonia turnover frequency of 15.1 grams of nitrogen per gram of metal per hour, up to four orders of magnitude higher than that reported in the literature, under both high removal efficiency and Faradaic efficiency of over 86% when treating influents with a low nitrate concentration of 100 milligrams of nitrogen per liter in a residence time on the order of seconds.
传统的用于硝酸盐还原的电化学反应器在应用于实际水处理时，由于电催化活性位点利用不佳，通常反应效率有限。在此，我们应用纳米多孔电过滤技术，通过将单原子催化剂融入带电膜中，在实际水条件下将低浓度硝酸盐还原为氨，以提高原子利用率。我们通过将催化剂涂覆在碳纳米管交织的膜框架上，增强纳米孔中单原子的暴露。电过滤增强了硝酸盐在具有高度暴露单原子活性位点的受限纳米孔中的传输和吸附，从而提高还原效果。该膜在处理每升含100毫克氮的低硝酸盐浓度进水时，在停留时间为秒级的情况下，具有15.1克氮每克金属每小时的卓越氨周转频率，比文献报道的高出多达四个数量级，同时去除效率和法拉第效率均超过86%。
