A series of imidazole containing crosslinked copolymer poly(divinylbenzene-co-N- vinylimidazole) (PDVB-VI-n) supported Au catalysts were prepared by using AuCI3 as the precursor. The resulting Au/PDVB-VI-n catalysts were employed to catalyze the aerobic oxidation of benzyl alcohol with molecular oxygen as the sole oxidant and water as the solvent. By optimizing the sizes of Au NPs and the composition of PDVB-VI-n, Au/PDVB-VI-n exhibited the excellent activities even only using a small amount of basic K2CO3. Interestingly, the conversion of benzyl alcohol increased monotonously with the increase of Au sizes in the range of 2-5 nm, but the selectivity to benzoic acid increased first and then decreased gradually. The highest selectivity to benzoic acid of similar to 80%was achieved over similar to 3.2 nm Au NPs. (C) 2017 Elsevier B.V. All rights reserved.