Preferential CO oxidation in a H-2-rich stream was studied over Au/ZnO and Au/ZnO-Fe2O3 catalysts prepared by photodeposition under Uv-vis light. The high catalytic activities of both Au/ZnO and Au/ZnO-Fe2O3 catalysts are presented over a temperature range of 30-130 degrees C. TEM results revealed that the average particle size of Au over the Au/ZnO and Au/ZnO-Fe2O3 catalysts, is in the range of 3-5 nm. Moreover, DR/UV-vis spectra showed that the prepared catalysts contained Au delta+ and Au-0 (active sites for the PROX reaction) on the catalyst support. Based on the experiment observations, it can be concluded that the catalysts prepared by a photodeposition exhibited excellent catalytic activity, even when both CO2 and H2O were added to the simulated stream. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.