Abstract
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.
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•Flower-lik P-doped rGO supported CoS/CoS2 heterostructure were obtained via simple hydrothermal method.•The rGO-CoS/CoS2 @ P5 delivered superior HER activity at low overpotential of 148 mV in acid electrolyte.•Excellent long-term durability with negligible variation in current density after 20 h chronoamperometry analysis.•The rGO-CoS/CoS2 @ P5 composite can be used as a good alternative for water splitting process.