Dissolved iron in alkaline media: Techniques and insights for understanding its effects on water-splitting reactions

Dissolved iron in alkaline media is an important topic influencing a wide array of electrochemical reactions and most notably those occurring in alkaline water electrolysers. This work compiles the study techniques and strategies that have been used in the past few years to help tackle this challenging issue. Focus is made on iron solubility in the studied medias, the importance of using a quality reference electrolyte, where and how to measure iron content in the system, and also on what is agreed and what is debated concerning the influence of dissolved iron on the hydrogen evolution reaction and oxygen evolution reaction, notably in the way these electrolyte impurities do enhance or alter the reactions kinetics.