The investigation of the effect of heat treatment on particle size, crystalline structure and photocatalytic activity of TiO2 nanoparticles

Photocatalytic degradation of organic pollutants in water and air is attracting much attention for application to environmental problems [1]. Titanium dioxide is one of the most widely studied semi-conducting photocatalysts for the degradation of organic contaminants [2]. There are many variables that affect the photoactivity such as particle size, crystal structure and preparation method of particles. particle size and crystal structure are considered as important factors that determines photoactivity. Therefore, in order to improve the photocatalytic activity, many reformative methods for TiO2 powder were adopted such as doping transition-metal ions and combination of other narrow band-gap semiconductor material [3].The photocatalytic efficiently depends on the rate of recombination of photoexcited electrons and holes. The photocatalytic mechanism involves the excitation of valence electrons to the conduction band by absorbing the UV light, resulting in the formation of holes can undergo subsequent reduction and oxidation before the recombination reaction [4]. In this work, the effect of heat treatment on particle size, crystalline structures and photocatalytic activity of TiO2 nanoparticles and decolorization of C.I. Acid Red 88 (AR88) as a model compound from monoazo anionic textile dyes have been investigated