The Effect of Metal Oxide Supports on the Activity of Pt-Ru Towards Methanol Electrooxidation

Several inexpensive but non-conductive materials (TiO 2 , CeO 2 , Al 2 O 3 and SiO 2 ) were chosen as supports for Pt-Ru electrocatalysts used for methanol oxidation. Although the metal oxide supports were found to have low conductivity, they have high surface area and could promote activity towards the desired reaction for heterogeneous catalysis. In order to increase the conductivity and make these electrodes (metal particles + support) suitable for electrochemistry; the metal nanoparticles were deposited onto the supports at loadings of 60 wt% metal. We aimed to determine if these non-conducting oxides could be used as supports for Pt-Ru to oxidize methanol electrochemically, and if the type of oxide affected activity. Using cyclic voltammetry experiments for methanol electrooxidation, it was demonstrated that for some of metal oxide supports, the activity of Pt-Ru towards methanol oxidation was excellent, even surpassing the activity of the same electrocatalysts supported on carbon. The results confirmed that the same loading of Pt-Ru electrocatalysts supported on these different metal oxides can have different activities for methanol electrooxidation. Pt-Ru/SiO 2 and Pt-Ru/anatase TiO 2 have showed the highest activity and Pt-Ru/anatase TiO 2 could be a good candidate also as its activity was the highest after the current was normalized by both the active site of the catalyst and by the mass of platinum metal deposited in the electrode.