Endrődi B, Samu A, Kecsenovity E, Halmágyi T, Sebők D, Janáky C
Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged, H-6720, Hungary.
Department of Applied and Environmental Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged, H-6720, Hungary.
Nat Energy. 2021 Apr;6(4):439-448. doi: 10.1038/s41560-021-00813-w. Epub 2021 Apr 19.
Continuous-flow electrolyzers allow CO reduction at industrially relevant rates, but long-term operation is still challenging. One reason for this is the formation of precipitates in the porous cathode from the alkaline electrolyte and the CO feed. Here we show that while precipitate formation is detrimental for the long-term stability, the presence of alkali metal cations at the cathode improves performance. To overcome this contradiction, we develop an operando activation and regeneration process, where the cathode of a zero-gap electrolyzer cell is periodically infused with alkali cation-containing solutions. This enables deionized water-fed electrolyzers to operate at a CO reduction rate matching that of those using alkaline electrolytes (CO partial current density of 420 ± 50 mA cm for over 200 hours). We deconvolute the complex effects of activation and validate the concept with five different electrolytes and three different commercial membranes. Finally, we demonstrate the scalability of this approach on a multi-cell electrolyzer stack, with a 100 cm / cell active area.
连续流动电解槽能够以与工业相关的速率实现CO还原，但长期运行仍然具有挑战性。造成这种情况的一个原因是在多孔阴极中由碱性电解质和CO进料形成了沉淀物。在这里我们表明，虽然沉淀物的形成对长期稳定性不利，但阴极处碱金属阳离子的存在会提高性能。为了克服这一矛盾，我们开发了一种原位活化和再生工艺，其中零间隙电解槽的阴极会定期注入含碱阳离子的溶液。这使得以去离子水为进料的电解槽能够以与使用碱性电解质的电解槽相匹配的CO还原速率运行（在超过200小时的时间内，CO分电流密度为420±50 mA/cm）。我们剖析了活化的复杂影响，并使用五种不同的电解质和三种不同的商业膜验证了这一概念。最后，我们在具有100 cm/单元活性面积的多电池电解槽堆栈上展示了这种方法的可扩展性。
