Activity of methanol electro-oxidation at PtRu materials at temperatures in the range of 23°C to 70°C

The electrochemical oxidation of 0.5 M methanol in 0.1 M HCIO4 on catalyst materials comprised of platinum and ruthenium (PtRu) was investigated. Cyclic voltammetry and constant potential amperometry were used to characterize the catalyst materials and study the methanol reaction kinetics. Measurements were performed at temperature in the range of 23°C to 70°C. The following catalyst materials were employed: PtRu black containing 50 at. % Ru supplied by Johnson Matthey of Ward Hill. MA (JM PtRu black); sonochemically prepared nanoparticles of PtRu containing either 50 at. % Ru (SC PtRu(50)) or 25 at. % Ru (SC PtRu(25)); and Pt black (supplied by Johnson Matthey) modified by spontaneous deposition of Ru via either two (JM Pt-Ru(2)) or four deposition cycles (JM Pt-Ru(4)).

The rate of methanol oxidation was assessed through constant potential amperometry measurements. Current was recorded 20 min after stepping to the reaction potential. Mechanistic information was derived from Tafel plots (plot of the logarithm of the current versus the reaction potential).