Preparation and Electrocatalytic Hydrogen Evolution Performance of CoS2:Mo Microrods

Cobalt disulfide (CoS2) features highly active catalytic sites and is regarded as a promising candidate for electrocatalytic hydrogen evolution. In this study, molybdenum-doped cobalt disulfide (CoS2:Mo) was synthesized via a facile hydrothermal approach. XRD analysis confirms that the obtained samples crystallize in a cubic pyrite structure, with diffraction peaks consistently shifting towards lower angles. SEM characterization reveals that the samples exhibit microrod-like morphologies with an average size of approximately 1 μm. Integrated analyses from XRD, XPS, and EDS mapping demonstrate that Mo is uniformly distributed across the surface and successfully doped into the CoS2 lattice. Electrochemical measurements indicate that the CoS2:Mo sample delivers a low overpotential of 122 mV and a Tafel slope of 128 mV dec−1 at a current density of 10 mA cm−2 in alkaline media, significantly surpassing the performance of pure CoS2 and MoS2. Moreover, the CoS2:Mo exhibits an enhanced double-layer capacitance, with a Cdl value of 2.72 mF cm−2, superior to that of pure CoS2 (1.63 mF cm−2) and MoS2 (0.31 mF cm−2). Mo doping enhances conductivity and active sites, thereby boosting electrocatalysis. This work presents an effective strategy for the development of cost-efficient and high-performance non-precious metal electrocatalysts.