Phosphorus co-doped reduced graphene oxide embedded flower-like CoS/CoS2 heterostructure as an efficient electrocatalyst for hydrogen evolution reaction in acidic media

The electrochemical efficacy of an electrocatalyst can be improved by an elaborate surface modification. In this study, phosphorus co-doped reduced graphene oxide embedded (rGO) flower like CoS/CoS2 heterostructures have been prepared, via one step hydrothermal process, by taking different mole ratio of phosphorus source for excellent hydrogen evolution reaction (HER) in acid solution. The as-fabricated catalysts are studied by XRD, FT-IR, XPS, SEM, EDS, and HR-TEM analyses. The rGO-CoS/CoS2 @P5 (5 mmol) catalyst exhibits a superior catalytic behavior for HER with a less overpotential (148 mV), low Tafel slope (44 mV dec−1) and enhanced cyclic durability (1000 cycles) in acid condition in comparison with other composition. The synergetic effect of hetero-interface and rapid charge transfer through rGO on the active sites of CoS/CoS2 have improved the HER efficiency. This study demonstrated that the component of rGO and P-incorporation on CoS/CoS2 interface offered an achievable yet easy strategy to synthesize platinum (Pt) free metal-based heterostructured catalyst as the favorable electrode material in sustainable energy applications.