Effects of reduction temperature and pH value of polyol process on reduced graphene oxide supported Pt electrocatalysts for oxygen reduction reaction

Effects of the reduction temperature and the pH value of Pt precursor solutions of the polyol reduction process on the resulted Pt electrocatalysts supported on the reduced graphene oxide (Pt/r-GO) nanosheets for the ORR (oxygen reduction reaction) are investigated. The Pt/r-GO catalyst possesses Pt nanoparticles having an average size from 2 to 4 nm and a Pt loading from 13 to 20 wt%. The electrochemical performance of the Pt/r-GO catalysts is examined with the glassy carbon RDE (rotating disk electrode) technique in the O2-saturated HClO4 (0.5 M) solution. The Pt/r-GO catalysts have less ORR limiting currents near 3.5 mA cm−2, but, in general, the more positive onset potentials than the commercial Pt/carbon black catalysts. The number of electron transfer in ORR over the Pt/r-GO catalysts is 3.85 in average, close to that of a 4-electron transfer process.