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In present findings, a simple pyrolysis technique was applied to decorate S and N doped graphene with RuS₂-CoO nanoparticles synthesizing a heterostructured nanocomposite RuS₂-CoO@SNG. XPS results demonstrate the elemental composition of these nanomaterials with the hint of metal-metal charge transfer phenomenon likely due to heterostructure composition. These modifications led to a significant active surface area resulting in elevated electrocatalytic performance. In comparison to benchmark Pt/C at -60 mV in 1 M KOH, hydrogen evolution reaction (HER) reached at current density around 10 mA cm^-2 at -90 mV overpotential. The stability test displayed excellent results with a decrease of 2 mV in overpotential at current density of 10 mA cm^-2. Results indicate that such heterostructured nanocomposites can be used as an effective catalyst for HER.