Two-dimensional Co3W3C nanosheets on graphene nanocomposition: An Pt-like electrocatalyst toward hydrogen evolution reaction in wide pH range

It is still a great challenge to replace Pt by non-precious metal electrocatalysts toward hydrogen evolution reaction (HER) due to their sluggish kinetics and poor electrochemical durability. Here, we reported a novel two-dimensional Co3W3C nanosheets on graphene nanocomposition (Co3W3C NSs/G) that synthesized by a simple two-step method. The overpotential of Co3W3C NSs/G at 10 mA cm(-2) (eta(10)) is just 64 mV in 0.5 M H2SO4 solution, which is very close to Pt/C (37 mV). The Tafel slope of Co3W3C NSs/G is 35 mV dec(-1), which is also very close to Pt/C (30 mV dec(-1)). The exchange current density (j(0)) of Co3W3C NSs/G is 0.232 mA cm(-2), which is almost as high as Pt/C (0.279 mA cm(-2)). Overall, the Co3W3C NSs/G exhibits Pt-like catalytic activity toward HER. Furthermore, the Co3W3C NSs/G shows outstanding HER activities and extreme high electrochemical durability in a wide pH range. The density functional theoretical (DFT) calculations show that the Gibbs free energy of hydrogen bonding (Delta G(H)*, * denotes an adsorption site) of the Co3W3C is -0.15 eV, which is also very close to Pt (-0.09 eV). (C) 2018 Elsevier Ltd. All rights reserved.