High catalytic activity of oxygen- vacancy- rich tungsten oxide nanowires supported by nitrogendoped reduced graphene oxide for the hydrogen evolution reaction

This paper reports on a catalyst composed of oxygen-vacancy-rich tungsten oxide nanowires supported by nitrogen-doped reduced graphene oxide (WOxNWs/N-rGO), which has an excellent catalytic activity for the hydrogen evolution reaction (HER) in an acid solution. WOxNWs/N-rGO were synthesized by solvothermally coupling tungsten oxide nanowires with melamine/graphene oxide followed by annealing. The WOxNWs/N-rGO exhibit only 40 mV of overpotential to afford a current density of 10 mA cm(-2), which is only 7.01 mV greater than that of Pt/C but 4.90 and 9.90 mV less than those of WOxNWs/rGO and WOxNWs, respectively. A durability test of WOxNWs/N-rGO reveals only a 14 mV overpotential shift after 5000 cycles at a large current density of 100 mA cm(-2). At a constant overpotential of 55 mV, the WOxNWs/N-rGO activity also exhibits a slight degradation of approximately 5.4% after 12 h. The outstanding performance of the WOxNWs/N-rGO for the HER is attributed to the synergetic effect between the oxygen-vacancy-rich WOxNWs and N-rGO.