Rhenium oxide-modified Ir/SiO2 (Ir-ReOx/SiO2) catalyst shows high activity and selectivity for the dehydrogenation of trans-1,2-cyclohexanediol to 2-hydroxycyclohexanone in water solvent under Ar. Linear vicinal diols bearing two secondary hydroxy groups or both a primary hydroxy group and a secondary hydroxy group can also be transformed to the corresponding alpha-hydroxy ketones in high selectivities. Ir-ReOx/SiO2 can be reused at least four times without loss of activity and selectivity.