Sr2CeO4-promoted photo-oxidation of gaseous benzene by UV/O-3 process was studied. The kinetic study reveals that the photo-degradation process is a pseudo first-order reaction; the relationship between the initial concentration and the reaction rate constants abides by exponent formula. The experimental results show that the addition of hydrogen peroxide can increase the conversion of benzene, while the process is still first-order reaction. GC/MS analysis of ether-extracted surface species confirms that the main intermediates are (3-methyl-oxiran-2-yl)- methanol, ethyl acetate and butylated hydroxytoluene. Finally, the photo-oxidation pathway was speculated consequently. (c) 2007 Elsevier B. V. All rights reserved.