Investigation of PtCo/Graphene and PtCoRu/Graphene Catalysts for Oxygen Reduction Reaction

The electrocatalytic oxygen reduction reaction (ORR) is an important process in energy converting systems such as low temperature proton exchange membrane fuel cells (PEMFCs). Therefore, understanding the oxygen reduction mechanistic pathways in terms of developing an efficient and stable catalyst has been the main research interest over several decades.

In the present study a rapid microwave heating method was used to prepare the graphene supported PtCo and PtCoRu catalysts with the different Pt:Co and Pt:Co:Ru molar ratios. The catalytic activity of the PtCo/graphene and PtCoRu/graphene catalysts, for oxygen reduction reaction was investigated by linear scan voltammetry in the cathodic direction at 5 mV s^–1 in the 0.5 M H₂SO₄ solution saturated with O₂ at a temperature of 25 ^oC. Physical characterization of the catalysts was performed by X-ray Diffraction, High Resolution Transmission Electron Microscopy, Energy Dispersive X-ray Analysis and Inductively Coupled Plasma Optical Emission Spectroscopy techniques. The cyclic voltammetry has been used to estimate the electrochemically active surface areas of the catalysts.

It was found that the PtCo/graphene and PtCoRu/graphene catalysts prepared by means of microwave synthesis show enhanced activity towards oxygen reduction as compared with that at bare Pt/graphene catalyst. The PtCo/graphene and PtCo /graphene catalysts show higher onset potentials, as well as higher current densities towards oxygen reduction reaction as compared with those at the bare Pt/graphene catalyst.