Electrocatalytic Performance of In2O3-Supported Pt/C Nanoparticles for Ethanol Electro-oxidation in Direct Ethanol Fuel Cells

Abstract

In2O3 supported Pt/C (Pt/C-In2O3) composite electrocatalysts has been prepared from In2O3 nanoparticles prepared by chemical reduction process and the commercially available Pt/C. X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) show that In2O3 nanoparticles are well distributed on Pt/C and In2O3 has the crystallite size of 20 nm. High resolution transmission electron microscopy (HR-TEM) also indicates that the In2O3 particles with a crystallite size of 5 nm are highly dispersed on the surface of the Pt/C. The Pt/C-In2O3 nanoparticles demonstrate a higher activity towards ethanol oxidation than Pt/C despite lower electrochemical surface area. Since Nafion membrane is not suitable for high operating temperature, the experiments are conducted using phosphoric acid doped polybenzimidazole (PBI) membrane. Fuel cell polarization data are obtained using Pt/C and Pt/C-In2O3 at different high operating temperatures with oxygen as oxidant and ethanol as fuel. In all the test conditions, the performance of Pt/C-In2O3 is found to be higher compared to that of Pt/C. This result indicates the active participation of In2O3 significantly improves the catalytic activity of Pt/C in the ethanol oxidation process. Hence, these results suggest that In2O3 supported Pt/C assembled with PBI membrane could be considered as an effective composite electrocatalyst for ethanol oxidation at high temperature in direct ethanol fuel cells.