Preparation Of Photocatalyst With High Activity And Study On Photocatalytic System

Titanium dioxide (TiO2) as photocatalyst has attracted much attention to remedying environmental pollution. But it has a lot of problems in industrial application. It is a bottleneck problem to immobilize photocatalysts and improve photocatalytic activity of TiO2 in a photocatalytic reaction system.The photocatalytic degradation kinetics of methyl orange (MO) was studie(investigated) under different conditions such as various catalyst concentration, pH, absorption behavior, HCO3" and in presence of electron acceptors such as H3PW]2O4o, H2O2 and KBrO3. The results showed that the appropriate concentration of TiO2 was 0.5g/L and the proper pH value accelerated the photodegradation rate of methyl orange. In addition, it indicated that the absorbing methyl orange ability of TiO2 decreased with the increasing of pH value, which was influenced by electron acceptor addition. The addition of these electron acceptors significantly enhanced the photodegradation rate of MO. The accepting electron abilities of electron acceptors result in different photocatalytic activities. In our investigations, the maximum pseudo-first-order degradation rate constants (KH3PW12O40= 19083 min-1, K H2O2=0.31285 min-1 and AocBioa=. 14294 min-1) were present at different concentration of electron acceptors (0.06mmol/L, H3PW12O40; 0.19mol/L, H2O2; O.lmol/L, KBrO3, respectively). And the efficiencies of photodegradation were higher as 1.7, 3.7 and 29 times as those of no HsPW12O40, H2O2 and KBrO3, respectively.In this paper, a modified sol-gel method for the preparation of TiO2 powder and thin films with high photocatalytic activity was described, while the photocatalytic properties were studied at the same time. This process included preparation of a polyester polymer by reacting citric acid with ethylene glycol. A Ti-O inorganic net was prepared by hydrolysis of titanium source. The new role of organic polymer for TiO2 powders and thin films growth by sol-gel method acts as in situ steric stabiliser to prevent particles congregating and thin films cracking during the calcinate treatment. The obtained powders and films were characterized by TG, DSC, UV-Vis, XRD, TEM and AFM. It showed that the crystal structures of the TiO2 powders and thin films were Anatase, and the crystal particle sizes of TiO2 powders and film were about 15 run and 40-50nm, respectively. The photocatalytic properties of photocatalyst were investigated by measuring the photodegradation oxidation of methyl orange under UV irradiation condition. The photocatalytic activities of the powders and the films were higher than those of the Degussa P-25 powders and P-25films at the same condition. The photodegradation rate of MO significantly was improved because of the addition of these electron acceptors in TiCh film photocatalytic system.