Operando interpretation of reaction mechanisms and local phenomena on OER catalysts in seawater electrolysis

Direct seawater splitting has great potential for constructing an economic hydrogen production system and resolving water scarcity via pure water production from evolved hydrogen. However, transforming electrocatalytic direct seawater splitting into a viable process is extremely challenging from an electrocatalytic point of view. A vast number of present ions and impurities in seawater, e.g. Na⁺, Mg²⁺, Cl⁻, SO4²⁻, Br⁻, disrupts efficient oxygen evolution reaction (OER) in anode or hydrogen evolution reaction in cathode. In this respect, there are different challenges posing on understanding the effect of the complex nature of seawater especially on the OER catalysts of seawater electrolysis. This mini-review covers different electrochemical and operando techniques used in order to understand the effect of ions present in seawater on activity, stability, and the equally important reaction selectivity of OER electrocatalysts.