Metal dot-on-ZnO type hierarchical nanostructures composed of ordered arrays of noble metal nanoparticles with controlled areal density, prepared from poly(styrene-block-vinyl pyridine) diblock copolymer inverse micelles loaded with metal precursors, on sol-gel process based similar to 48 nm thick ZnO thin films exhibit enhanced photocatalytic activities compared with pure ZnO thin films in terms of photodegradation of methylene blue. (C) 2010 Elsevier Inc. All rights reserved.