Chapter 3: Bifunctional Electrocatalysts for Water Splitting

With the aim of bringing future renewable energy resources into reality, searching for effective bifunctional electrocatalysts for overall water splitting, i.e. both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), can be considered pivotal. On the other hand, water electrolysis is being examined as an ideal technique to produce hydrogen on a massive scale. So far, most water electrolysers work effectively using either acidic or alkaline media. However, from the industrial perspective, today the development of noble metal-free, stable electrocatalysts for overall water splitting in neutral media is of paramount interest. This chapter discusses recent developments in bifunctional electrocatalysts. Particular attention is paid to cobalt-based, metal–organic framework (MOF)-based bifunctional electrocatalysts and those that work efficiently in neutral media. An example is presented with a Co–TDC electrocatalyst, obtained from thiophene-2,5-dicarboxylic acid, which exhibited a current density of 10 mA cm⁻² at 1.96 V in 1 M phosphate-buffered saline solution, with almost 24 h stability for overall water splitting.