PLATINUM-CERIUM OXIDE COMPOSITE ELECTROCATALYSTS WITH ENHANCED ELECTROCATALYTIC ACTIVITY TOWARD METHANOL OXIDATION REACTION
Abstract - Platinum-amorphous cerium oxide composite electrocatalysts are synthesized, and their activity toward methanol oxidation reaction (MOR) is investigated in this study. Using polyol method with precursors containing Pt/Ce mole ratios of 100/0, 80/20, 60,40 and 50/50, electrocatalysts of Pt/C, Pt80Ce20/C, Pt60Ce40/C, and Pt50Ce50/C are obtained. Transmission electron microscope images show that Pt nanoparticles with an average diameter of about 3 nm are evenly distributed on carbon black surfaces. The Pt/Ce ratios are similar to those in the precursors. The presence of cerium species is confirmed by scanning electron microscope-energy-dispersive X-ray spectroscopy analysis. Only Pt crystalline diffraction peaks are observed in X-ray Diffraction spectra, which inferred that the cerium species are in amorphous form. They should be cerium oxides since cerium can be easily tarnished in are. Cyclic voltammetry experiments indicated that Pt60Ce40/C exhibited superior MOR catalytic activity. Chronoamperometry experiments suggested that Pt60Ce40/C might have better carbon monoxide-tolerance ability than other electrocatalysts tested. It is deduced that the electrocatalytic activity toward MOR is enhanced through the bifunctional mechanism.
Keywords - Methanol Oxidation Reaction, Electrocatalyst, Platinum, Ceria, Carbon Monoxide-Tolerance.