HY zeolite-supported Au clusters ((AuHY)-H-0) prepared by deposition-precipitation method, well characterized by XANES. EXAFS, and NH3- and acetyl acetone-adsorption IR, were tested for addition of acetyl acetone to alkenes. (AuHY)-H-0 showed higher selectivity to the addition product than HY zeolite-supported Au(OH)(3) and Au clusters supported on NH4+-exchanged Y zeolite, Al2O3, MgO, SiO2, and TiO2. Studies on the effect of Au oxidation state, Au cluster size and Bronsted acidity of zeolite on the catalytic showed that co-presence of metallic Au with smaller cluster size and the acidic OH groups of the zeolite was necessary to the selective formation of the addition product. Cooperation mechanism of the Bronsted acid sites of the zeolite and Au clusters is proposed. (C) 2011 Elsevier B.V. All rights reserved.