Hydrothermal Synthesis and ORR Performance of Tungsten Disulfide/Reduced Graphene Oxide Composite

Two-dimensional tungsten disulfide/reduced graphene oxide (WS2/RGO) composite was synthesized by one-step hydrothermal method using tungsten hexachlorid, thioacetamide and graphene oxide (GO) as precursors. Due to the presence of graphene, WS2 with few layers is uniformly grown on the surface of RGO. We attempted to employ this non-Pt material as an electrocatalyst for oxygen reduction reaction (ORR). Test results indicate that the ORR activity of WS2 in alkaline electrolyte is actually very low. However, after the formation of WS2/RGO composite, the electrocatalytic performance has been greatly improved. The composite shows an initial potential of -0.17 V (vs SCE) and the limiting current density is 2.5 mA.cm(-2). Besides, the number of transfer electrons in ORR is 3.7, which is nearly comparable to that of commercial Pt/C (20%). Moreover, it shows remarkable durability and better resistance toward methanol crossover in ORR. It is thought that WS2/RGO has better electronic conductivity and WS2 can play a synergistic catalytic effect with RGO. As a result, the novel WS2/RGO material as a non noble metal catalyst in fuel cells is considerably promising.