Ultra-Small Ceria Nanocrystals at Carbon Surface Synthesized by Ultrasound Sonication: A Study of Highly Active Platinum-Cerium Bifunctional Catalysts for Methanol Oxidation and Oxygen Reduction

Abstract

In this study, 0.7 nm CeO2 crystallites were synthesized by a sonochemical method to prepare a highly active PtCe catalyst material for methanol oxidation and oxygen reduction reaction. The obtained materials contained Pt nanoparticles with a crystallite size of 1 nm and were well dispersed on the surface of carbon material. This is confirmed by ECSA as high as 89 mPt 2 gPt −1. The PtCe materials synthesized on Ketjenblack carbon with small CeO2 were more favorable with methanol oxidation (MOR) in the mixture of 0.5 mol dm−3 H2SO4 and 1 mol dm−3 CH3OH. The MOR mass activity was as high as 200 A gPt −1 after 1-hour chronoamperometry measurement at 0.85 V vs RHE. The PtCe synthesized on chromium carbide-derived carbon material was more favorable to oxygen reduction (ORR) in 0.1 mol dm−3 HClO4 saturated oxygen. The ORR mass activity at 0.9 V vs RHE was 304 A gPt −1. The Pt deposition method was optimized and repeatable.