Depositing reduced graphene oxide onto tungsten disulfide nanosheets via microwave irradiation: confirmation of four-electron transfer-assisted oxygen reduction and methanol oxidation reaction

Optimal morphology tailoring and complete utilization of the nanomaterial components are the effective parameters for improving the electrocatalytic activity of nanomaterials in both the oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR). In the present work, a core-shell reduced graphene oxide (rGO) on tungsten sulfide (WS2),i.e., rGO@WS(2)nanostructure was successfully preparedviamicrowave irradiation, which was found to catalyze the four-electron ORR in a 0.1 M KOH aqueous solution. The rGO@WS(2)nanostructure showed an onset potential of 0.94 V and a 1.68-fold increase in the kinetic current density (-5.9 mA cm(-2)) for the ORR as, compared to the bare WS(2)nanosheets. The superior performance of the rGO@WS(2)nanostructure posits it as one of the efficient noble-metal-free ORR and MOR electrocatalysts. Predominantly, this work demonstrates the importance of an appropriate core-shell rGO@WS(2)nanostructure in achieving high intrinsic activity for the four-electron ORR and MOR with significantly enhanced efficiency.