The nano-sized Co2CrO4 spinel was produced for the first time by thermal decomposition of Cr-Co gel prepared by sol-gel method. It was shown that well-crystallized spinel structure is formed after calcination at 450 degrees C. The usual characterizations were performed and the results showed the particle size of the prepared spinel is 9 nm. Moreover, the prepared nano-sized Co2CrO4 spinel was applied in a simple, efficient and recyclable method for selective oxidation of sulfides to their corresponding sulfoxides with aqueous hydrogen peroxide in tert-butanol. (C) 2011 Elsevier Ltd. All rights reserved.