Nanostructured Pt-ZnO composite thick films were prepared using the composite nanoparticles synthesized through Triton X-100 polymer assisted thermolysis of zinc acetate. It has been observed that only a fraction of added Pt incorporates into the ZnO lattice and the rest segregates over the ZnO nanoparticle surface to form metallic nanoclusters. Morphology. crystallinity, and optical properties of the ZnO and Pt-ZnO nanostructures have been studied. Photocatalytic behavior of the samples for phenol degradation process has been studied in a high performance liquid chromatography system. It has been observed that though the phenol degradation rate is higher for pure ZnO nanostructures, Pt-ZnO nanostructures act as selective catalyst, producing only one intermediate product and dissociating it faster than ZnO. (C) 2011 Elsevier B.V. All rights reserved.