A new facile approach to prepare reduced graphene oxide and MoO2/reduced graphene oxide as electrode materials for oxygen reduction reactions

A facile one-pot method for the formation of MoO2/RGO has been established using Mo particles as both the reductant for graphene oxide (GO) and as the Mo source. The Mo powder efficiently reduced the GO under acidic conditions to give reduced GO (RGO) and Mo ions. These ions were then transformed into MoO2 and MoO2/RGO composites were formed by tuning the pH of the solution. Other variables such as reaction time and Mo:GO weight ratio were also investigated. The MoO2/RGO composite prepared at 3:1 (Mo:GO, called MoO2/RGO(3)) had the best electrochemical performance for the oxygen reduction reaction (ORR) in alkaline medium. The ORR reaction at the MoO2/RGO(3) electrode mainly proceeded via a four-electron pathway and the electrode displayed superior catalytic activity and good stability. These results indicate that MoO2/RGO(3) could be a promising noble metal-free electrocatalyst for fuel cells. (C) 2017 Published by Elsevier Inc.