In situ demonstration of anodic interface degradation during water electrolysis: Corrosion and passivation

Abstract

Understanding of interface-driven performance degradation in the oxygen evolution reaction (OER) is a prerequisite for developing long-term electrolytic systems operating at maximum efficiency. The question remains as to whether in situ observation of degradation during OER will be possible. We design a model system and fabricate a structure that is ideal for in situ detection of interfacial degradation that could occur at the anode, i.e. corrosion and passivation. The synthesized structure is based on carbon (C) or non carbon (Ti); this is not only because it is a practical and general choice as an anode substrate, but also because it can represent the degradation reaction of corrosion or passivation, respectively. Interfacial responses from the ideally structured surface are observed (spectro)electrochemically under OER-operating conditions. We reveal that while electrochemical oxidation of C is inevitable over time, the passivation of Ti can be circumvented under controlled conditions. We also disclose that the use of Ti can be more beneficial for electrolytic cells, than that of C. These results highlight future research strategies required for the optimization of Cand Ti-based components used in electrolytic cells. (c) 2020 Elsevier Ltd. All rights reserved.