The Influence of Morphology on Photo-catalytic Activity and Optical Properties of Nanocrystalline ZnO Powder

Javad Moghaddam,Sara Mollaesmail,Saeed Karimi

doi:10.1007/bf03353714

Abstract

Abstract ZnO nano-particles were synthesized via an ammonical ammonium carbonate solution by precipitation method in presence of some additives such as urea, oleic and stearic acid. The morphology and crystallinity of the obtained zinc oxide particles depend critically on the type of additive which was used. Additives also affected the crystal orientation of precipitate nano-particles. SEM, XRD, BET and UV-visible were used to characterize morphology, microstructure, specific surface area and optical properties of the products. Photo-catalysis properties of the as-prepared ZnO powders were evaluated by degradation of methyl red (acid red) in aqueous solution exposed to UV-light. Results suggested a close relationship among the morphology, size and surface area on photo-catalysis and optical properties of the particles. The widest Eg value (3.56 eV), highest degradation and decolorization efficiency (99%) were obtained from a sample with the smallest grain size (largest surface area) which were used urea as an additive.

Highlights

ZnO is normally an n-type semiconductor with a wide and direct band gap of 3.37 eV and a large exciton binding energy of 60 meV [1,2,3,4]
It is evident that the desired chemical and physical properties, and the optical properties and photo-catalytic activity strongly related to the particle sizes and shapes of ZnO powders [10]
In this study ZnO nano-particles that were obtained via an ammonical ammonium carbonate zinc aqueous solution precipitation with additives such as Urea, Oleic and Stearic acid were used for characterization

Summary

Introduction

ZnO is normally an n-type semiconductor with a wide and direct band gap of 3.37 eV and a large exciton binding energy of 60 meV [1,2,3,4]. It is evident that the desired chemical and physical properties, and the optical properties and photo-catalytic activity strongly related to the particle sizes and shapes of ZnO powders [10]. In this study ZnO nano-particles that were obtained via an ammonical ammonium carbonate zinc aqueous solution precipitation with additives such as Urea, Oleic and Stearic acid were used for characterization.

Results

Conclusion