CoP nanoparticles deposited on reduced graphene oxide sheets as an active electrocatalyst for the hydrogen evolution reaction

A novel composite with CoP nanoparticles uniformly deposited on reduced graphene oxide (RGO) sheets is prepared through a facile two-step approach. The as-prepared CoP/RGO composite is investigated as an electrocatalyst for the hydrogen evolution reaction (HER). It is found that the CoP/RGO composite shows an enhanced catalytic activity with a smaller Tafel slope (104.8 mV per decade), a much larger exchange current density (4.0 x 10(-5) A cm(-2)) and lower estimated HER activation energy (41.4 kJ mol(-1)) than pure CoP. Besides, the CoP/RGO composite exhibits good stability in acidic solution, the HER catalytic activity of which shows no obvious degradation after 500 cycles. Such enhanced catalytic activity stems from the abundance of active catalytic sites, the increased electrochemically accessible surface area and significantly improved electrochemical conductivity of the CoP/RGO composite. The good catalytic activity demonstrates that the CoP/RGO composite could be a promising electrocatalyst in hydrogen production.