Electrocatalytic Performance of Pt–Ru–Co/MC Electrode for Methanol Oxidation in Non-membrane Power System

Abstract

The present work represents the mesoporous carbon supported Pt100, Pt50Ru50, Pt50Co50, Pt60Ru20Co20, Pt60Ru10Co30 and Pt60Ru30Co10 catalysts with different mass ratios have been prepared by Pechini method. The crystallite size, lattice parameter, composition, and particle size of metals in the electrocatalysts were determined by XRD, EDX and TEM techniques, respectively. X-ray diffraction analysis showed that catalysts have a Pt face-centred cubic (fcc) structure with crystallite size of 3–4.5 nm. The EDX results of the binary Pt–Ru/MC and Pt–Co/MC and the ternary Pt–Ru–Co/MC catalysts were extremely close to the nominal values, indicating that the metals were loaded onto the mesoporous carbon support without any obvious loss. The size of catalyst nanoparticles was observed via TEM and showed an average diameter of 3.3 nm. The electrocatalytic activities of Pt100/MC, Pt50Ru50/MC, Pt50Co50/MC, Pt60Ru20Co20/MC, Pt60Ru10Co30/MC and Pt60Ru30Co10/MC catalysts were investigated in terms of CV and CA. The electrochemical results showed that the catalytic activity in 1.0 M MeOH + 0.5 M H2SO4 solution at 0.5 V vs. Ag/AgCl exhibits the following sequence: Pt60Ru30Co10/MC > Pt60Ru20Co20/MC > Pt60Ru10Co30/MC > Pt50Ru50/MC > Pt100/MC > Pt50Co50/MC. This clearly indicates that the performance of the ternary Pt60Ru30Co10/MC electrocatalysts for methanol electro-oxidation is better than that of the binary Pt50Ru50/MC and Pt50Co50/MC electrocatalysts due to the promoting function of Co. In addition, its CO-tolerance is better than that of the Pt50Ru50/MC and Pt50Co50/MC catalysts. The high activity of Pt60Ru30Co10/MC electrocatalyst was also observed on membraneless methanol fuel device, which was consistent with the half-device measurements.