Evaluation of Activity of Platinum-Ruthenium-Cobalt/Graphene Catalysts towards Methanol Oxidation

A simple approach – microwave synthesis was used to prepare platinum-ruthenium-cobalt/graphene catalysts (denoted as Pt-Ru-Co/GR). A series of Pt-Ru-Co/GR with the different molar ratios were prepared by microwave-assisted heating of the reaction mixture consisting of H₂PtCl₆, RuCl₃, CoCl₂ and ethylene glycol. The Transmission Electron Microscopy (TEM) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) were employed to characterize the synthesized Pt-Ru-Co/GR catalysts. The electrocatalytic activity of the synthesized catalysts towards the oxidation of methanol and CO was investigated by means of cyclic voltammetry and chrono-techniques. The electrochemically active surface areas of the prepared catalysts were determined from the cyclic voltammograms of the Pt-Ru-Co/GR catalysts recorded in a deaerated 0.5 M H₂SO₄ solution at a sweep rate of 50 mV s^–1 by calculating the charge associated with hydrogen adsorption (220 µC cm^-2).

It was found that the Pt-Ru-Co/GR catalysts with the Pt:Ru:Co molar ratios equal to 1:2:2, 1:1.7:5.6 and 3.5:1:23 were prepared. The EDX analysis confirm the presence of Pt, Ru and Co nanoparticles in the investigated PtCoRu/GR catalysts.

It has been determined that the Pt-Ru-Co/GR catalyst with the Pt:Ru:Co molar ratio equal to 3.5:1:23 has a higher electrocatalytic activity towards the oxidation of methanol in acidic medium as compared with that of other synthesized catalysts.