Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft, 2629 HZ, The Netherlands.
ChemSusChem. 2022 Jan 21;15(2):e202102180. doi: 10.1002/cssc.202102180. Epub 2021 Dec 9.
The application of a polymer electrolyte membrane (PEM) electrolytic cell for continuous conversion of nitrate, one of the contaminants in water, to ammonia at the cathode was explored in the present work. Among carbon-supported metal (Cu, Ru, Rh and Pd) electrocatalysts, the Ru-based catalyst showed the best performance. By suppressing the competing hydrogen evolution reaction at the cathode, it was possible to reach 94 % faradaic efficiency for nitrate reduction towards ammonium. It was important to match the rate of the anodic reaction with the cathodic reaction to achieve high faradaic efficiency. By recirculating the effluent stream, 93 % nitrate conversion was achieved in 8 h of constant current electrolysis at 10 mA cm current density. The presented approach offers a promising path towards precious NH production from nitrate-containing water that needs purification or can be obtained after capture of gaseous NO pollutants into water, leading to waste-to-value conversion.
本工作探索了在聚合物电解质膜 (PEM) 电解槽中应用阴极连续将硝酸盐（水中的一种污染物）转化为氨的方法。在碳载金属（Cu、Ru、Rh 和 Pd）电催化剂中，基于 Ru 的催化剂表现出最佳性能。通过抑制阴极上竞争的析氢反应，可以达到 94%的硝酸盐还原为铵的法拉第效率。重要的是要使阳极反应和阴极反应的速率相匹配，以实现高的法拉第效率。通过再循环流出物流，在 10 mA·cm-2 的恒定电流电解 8 h 内实现了 93%的硝酸盐转化率。该方法为从含硝酸盐的水中生产有价值的 NH 提供了一条很有前途的途径，这些水需要净化，或者可以在将气态 NO 污染物捕获到水中后获得，从而实现废物转化为有价值的物质。
