Vass Ádám, Endrődi Balázs, Samu Gergely Ferenc, Balog Ádám, Kormányos Attila, Cherevko Serhiy, Janáky Csaba
Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary.
Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Forschungszentrum Jülich GmbH, Egerlandstraße 3, 91058 Erlangen, Germany.
ACS Energy Lett. 2021 Nov 12;6(11):3801-3808. doi: 10.1021/acsenergylett.1c01937. Epub 2021 Oct 7.
A major goal within the CO electrolysis community is to replace the generally used Ir anode catalyst with a more abundant material, which is stable and active for water oxidation under process conditions. Ni is widely applied in alkaline water electrolysis, and it has been considered as a potential anode catalyst in CO electrolysis. Here we compare the operation of electrolyzer cells with Ir and Ni anodes and demonstrate that, while Ir is stable under process conditions, the degradation of Ni leads to a rapid cell failure. This is caused by two parallel mechanisms: (i) a pH decrease of the anolyte to a near neutral value and (ii) the local chemical environment developing at the anode (i.e., high carbonate concentration). The latter is detrimental for zero-gap electrolyzer cells only, but the first mechanism is universal, occurring in any kind of CO electrolyzer after prolonged operation with recirculated anolyte.
CO电解领域的一个主要目标是用一种更丰富的材料替代常用的Ir阳极催化剂，这种材料在工艺条件下对水氧化稳定且具有活性。Ni广泛应用于碱性水电解，并且已被视为CO电解中的一种潜在阳极催化剂。在此，我们比较了使用Ir和Ni阳极的电解槽的运行情况，并证明，虽然Ir在工艺条件下稳定，但Ni的降解会导致电池迅速失效。这是由两个并行机制引起的：（i）阳极电解液的pH值降至接近中性的值，以及（ii）阳极处形成的局部化学环境（即高碳酸盐浓度）。后者仅对零间隙电解槽有害，但第一种机制是普遍存在的，在用循环阳极电解液长时间运行后，在任何类型的CO电解槽中都会出现。
