Preparation Of Photocatalytic TiO₂ Film By Pyrolysis Method

Pyrolysis of chelated titanium alkoxide in ethanol solvent to prepare titania thin film was studied in this thesis. Titanium alkoxide solution was prepared by dissolving titanium alkoxide into ethanol solvent, adding appropriate amount of AcAc and PEG, and magnetically stirring in a beaker. Titania film was prepared by spin-coating the titanium alkoxide on a glass substrate, drying in atmosphere, and thermal treating at rather high temperature for some time.The influence of titanium alkoxide concentration, AcAc concentration, and binder PEG on the photocatalytic properties of titania film was investigated. Best result was obtained as following: ethanol 10ml, titanium alkoxide 4ml, AcAc 2.5ml, and PEG 60mg. The influence of coating times on the photocatalysis of titania film was also studied, and result shows 5 time is best for photocatalysis. The thermal treatment temperature was determined by conducting and analyzing the TG/DTA and FT-IR spectroscopy, and proper temperature is 500℃. The influence of metal ion doping was investigated to find that titania films exhibit better photocatalytic properties when doped with Sn⁴⁺ and Cu²⁺, at the amount of 10mg and 15mg respectively. The precursor solutions of titanium alkoxide with different amount of AcAc were characterized by DTA to study the chelating process of titanium alkoxide with AcAc. ATR analysis of the thin film on the glass substrate after thermal treatment showed the existence of Ti-O bond.The pyrolysis temperature and product of precursor solutions were characterized by TG/DTA and FT-IR. The crystalline properties and morphology of titania film were characterized by XRD and AFM, and the photocatalytic property was characterized by degradation rate of methyl orange solution.