Photodegradation of indigo carmine and methylene blue dyes in aqueous solution by SiC-TiO2 catalysts prepared by sol-gel

Abstract

Indigo carmine and methylene blue dyes in aqueous solution were photodegraded using SiC-TiO(2) catalysts prepared by sol-gel method. After thermal treatment at 450°C, SiC-TiO(2) catalysts prepared in this work showed the presence of SiC and TiO(2) anatase phase. Those compounds showed specific surface area values around 22-25 m(2)g(-1), and energy band gap values close to 3.05 eV. In comparison with TiO(2) (P25), SiC-TiO(2) catalysts showed the highest activity for indigo carmine and methylene blue degradation, but this activity cannot be attributed to the properties above mentioned. Therefore, photocatalytic performance is due to the synergy effect between SiC and TiO(2) particles caused by the sol-gel method used to prepare the SiC-TiO(2) catalysts. TiO(2) nanoparticles are well dispersed onto SiC surface allowing the transfer of electronic charges between SiC and TiO(2) semiconductors, which avoid the fast recombination of the electron-hole pair during the photocatalytic process.