Preparation of zno supported gold nanocrystals: Briefly, The Zno mesocrystals were prepared by calcination at 300°C for 6 h an further applications. Then, Au was deposited on the zno Mcs from solution mixed with Zno MC's at a pH value of about 9.5 for 48 h with stirring. The sample was washed with deionized water by centri fugation multiple times. Finally, the Au-loaded zno MCs were treated with 10% O, in He flow at 200°C for 1.5 h