Graphitic Carbon Nitride-Decorated Cobalt Diselenide Composites for Highly Efficient Hydrogen Evolution Reaction.

Transition-metal dichalcogenides have emerged as promising non-noble-metal electrocatalysts for efficient hydrogen production through the hydrogen evolution reaction (HER). In this work, we fabricated the graphitic carbon nitride-decorated cobalt diselenide (gC3N4-CoSe2) nanocomposites via the facile hydrothermal method. The prepared gC3N4-CoSe2 nanocomposites displayed an interconnected and aggregated morphology of gC3N4-decorated CoSe2 nanoparticles with offering large surface area of 82 m2/g. The gC3N4-CoSe2 nanocomposites exhibited excellent HER activity with a low overpotential (141 mV) and tiny Tafel slope (62 mV/dec) with excellent durability for 100 h at 10 mA/cm2 in an alkaline electrolyte. These outstanding HER performances of gC3N4-CoSe2 can be ascribed to the synergistic interaction between the electrochemically active porous CoSe2 nanoparticles and the highly conductive gC3N4 nanosheets. These results indicate that the gC3N4-CoSe2 nanocomposites hold promising and efficient HER electrocatalysts for sustainable green hydrogen production.