Temperature Effect on the Photocatalytic Degradation of Methyl Orange under UV-vis Light Irradiation

PTA sol was prepared using titanium tetrachloride （TiCl4）, hydrogen peroxide （H2O2） and ammonia （NH3·H2O）, and then stable anatase-TiO2 hydrosol was synthesized by refluxing the PTA sol at 100 ℃. It was found that TiO2 hydrosol can efficiently photo-degrade methyl orange （MO） under UV-vis light irradiation. Photocatalytic reactions at the temperature of 38 to 100 ℃ all followed pseudo-first-order rate law, and the temperature had a great effect on the reaction rate. The rate constants increased by about 6 times from 3.52×10^-4 to 2.17×10^-3 min^-1 when the temperature was adjusted from 38 to 100 ℃. Consequently, this photocatalytic course can be accelerated by using the infrared light of solar energy to increase the temperature of the photo-catalytic reaction, it should be a potential way to make full use of solar light in photocatalysis in practice.