To determine the kinetic performance of the electro-oxidation of a polyalcohol operating at relatively high temperatures, direct electrochemical oxidation of ethylene glycol on a carbon supported platinum catalyst (Pt/C) was investigated at intermediate temperatures (235-255 degrees C) using a single cell fabricated with a proton-conducting solid electrolyte, CsH2PO4, which has high proton conductivity (>10(-2) S cm(-1)) in the intermediate temperature region. A high oxidation current density was observed, comparable to that for methanol electro-oxidation and also higher than that for ethanol electro-oxidation. The main products of ethylene glycol electro-oxidation were H-2, CO2, CO and a small amount of CH4 formation was also observed. On the other hand, the amounts of C-2 products such as acetaldehyde, acetic acid and glycolaldehyde were quite small and were lower by about two orders of magnitude than the gaseous reaction products. This clearly shows that C-C bond dissociation proceeds almost to completion at intermediate temperatures and the dissociation ratio reached a value above 95%. The present observations and kinetic analysis suggest the effective application of direct alcohol fuel cells operating at intermediate temperatures and indicate the possibility of total oxidation of alcohol fuels. (C) 2011 Elsevier Ltd. All rights reserved.