HREELS study of Au/Fe2O3 thick film gas sensors

CO gas sensors based on Au-doped/Fe2O3 thick films were studied in ultra-hi gh-vacuum (UHV) by high resolution electron energy loss spectroscopy (HREEL S). Several adsorbed species were identified on HREEL spectra collected at room temperature on thick films annealed at different temperatures. Among t hese, carboxylate and formate species were postulated as intermediates of t he complex reactions occurring on the surface between carbon monoxide and o xygen. The catalytic and sensing properties of the Au/iron oxide samples towards C O have been also investigated showing the better performances of the co-pre cipitated samples in comparison to impregnated ones and the influence of an nealing temperature. Data reported were correlated to the presence of oxyge nate intermediates detected by HREELS. (C) 2001 Elsevier Science B.V. All r ights reserved.