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 °C. 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 °C 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 °C. 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.