We report a facile and efficient chemical approach for the controllable preparation of Au/SiOx composite thin film using silicon quantum dots as SiOx sources. Au/SiOx composite thin film exhibits high catalytic activity (65.04% conversion based on cis-cyclooctene and 78.34% selectivity for 2-hydroxycyclooctanone) and stability for selective oxidation of cis-cyclooctene in the absence of solvent using TBHP as radical initiator and oxygen (in the air) as oxidant at 80 degrees C. (c) 2013 Elsevier Ltd. All rights reserved.