Mesoporous Ag/ZnO multilayer films prepared by repeated spin-coating for enhancing its photonic efficiencies

The aim of the present work is to enhance the photonic efficiency of mesoporous ZnO films by photodeposition of Ag nanoparticles. Mesoporous ZnO multilayer films were synthesized by a sal-gel method in the presence of triblock co-polymer Pluronic (F-127) as a template agent, followed by spin coating on soda lime glass substrates. The as-prepared mesoporous ZnO films with different layers (1-10) were calcined at 450 C for 3 h. Ag nanopartides were photodeposited onto mesoporous ZnO multilayer films. XRD results of Ag/ZnO films indicated that ZnO nanoparticles had a hexagonal wurtzite structurewith a highly crystalline state. TEM images revealed that Ag nanopardcles are agglomerated and all pores can be regarded as irregular voids between ZnO particles and the prepared films have a large amount of voids. The prepared films have been evaluated by the determination of their photonic efficiencies during degradation of methylene blue (MB). The photonic efficiencies of mesoporous ZnO and AgfZnO films were found to improve with increasing number of layers from 1 to 5 and a further increase in film thickness (10 layers) doesn't lead to any enhancement in photoactivity. MB photodegradation was enhanced significantly when Ag was photodeposited onto ZnO using 5 layers with 1.165% photonic efficiency. The prepared Ag/ZnO with different layers demonstrates a highly stable nature of the designed photocatalyst with almost the same photocatalytic performance after 10 repeated cycles. (C) 2014 Elsevier B.V. All rights reserved.