Creating active interfaces as a strategy to improve electrochemical water splitting reactions

Electrochemical water splitting has received significant attention recently for the production of green hydrogen as a means to alleviate our need on fossil fuels. There has been immense progress on developing new catalysts that are active for the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER) as well as materials that are bifunctional and are active for both reactions. In this perspective I detail recent developments in tailoring highly active interfacial regions in a variety of catalysts that are suitable for these reactions. In particular the doping of metal oxides and metal-chalcogenides with a secondary metal is discussed and how this influences the activity and stability of the catalyst and how in fact simple systems such as Ni/NiO are also highly active due to the presence of a metal/metal oxide interface. Finally the future direction in characterising electrocatalysts is discussed and the important role that spatially resolved electrochemical data combined with other surface science techniques can be used to study structure-activity relationships at a localised level at such important interfaces.