Hierarchical Cobalt Sulfide/Molybdenum Sulfide Heterostructure as Bifunctional Electrocatalyst towards Overall Water Splitting

The development of non-noble metal based electrocatalysts for overall water splitting is a potent strategy towards a carbon-neutral and clean energy economy. Herein, hierarchical CoSx@MoS2 was synthesized via a one-pot solvothermal process. Formation of the heterostructure was confirmed by electron microscopy and spectroscopic techniques. CoSx@MoS2 showed competent electrocatalytic activity towards both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline medium. Superior electrocatalytic activity was attributed to the increase in number of active sites, betterment in charge transfer and facilitation of H- and O- containing active species adsorption-desorption at the active sites. Overall water splitting efficiency of CoSx@MoS2 was found to be superior in comparison to the state-of-the-art RuO2-Pt/C couple. Along with efficiency the heterostructure also exhibited long-term operational durability. Thus, hierarchical CoSx@MoS2 is a potential non-noble metal based bifunctional electrocatalyst towards overall water splitting.