Reduced graphene oxide supported Co3W and WN hybrid as high performance electrocatalyst for hydrogen evolution reaction

Hydrogen, as the most environment-friendly fuel, is believed as the eventual energy for human beings. The produce, storage and transportation of hydrogen are crucial technologies for the large-scale applications of hydrogen. Electrolysis is one of the most feasible way to produce hydrogen despite the shortage of low-cost and high-performance catalysts. Developing high cost-effective non-precious metal-based electrocatalysts for hydrogen evolution reaction (HER) is crucial for the production of hydrogen. In this paper, reduced graphene oxide (rGO) supported cobalt-doped tungsten nitride (Co-WN/rGO), tungsten-cobalt alloy and tungsten nitride hybrid (Co 3 W-WN/rGO) were prepared by hydrothermal followed with nitridation treatment method. XRD, SEM and XPS tests show that the Co 3 W-WN hybrids are uniformly dispersed on the rGO support. HRTEM clearly proved the coexistence of Co 3 W and WN on rGO. Electrocatalytic performance tests of Co-WN/rGO and Co 3 W-WN/rGO show that the overpotential of Co 3 W-WN/rGO-1-800 catalyzed HER is lower than that of 20 wt% Pt/C in 0.1 M KOH solution at current density of 60 mA/cm 2 . In addition, in 0.5 M H 2 SO 4 solution, the overpotential of Co 3 W-WN/rGO-1-800 catalyzed HER is only 83 mV higher than that of the Pt/C catalyst at the current density of 300 mA/cm 2 . The high catalytic performance should be attributed to the synergistic effect between Co 3 W and WN. The results of the paper provide a novel strategy to design high performance transition metal-based catalysts for HER and give a new insight into the catalytic mechanism.