Synthesis of Ag/TiO2 composites by combustion modified and subsequent use in the photocatalytic degradation of dyes

Abstract

In this work, the synthesis of Ag/TiO2 photocatalysts by the modified combustion method for the degradation of dyes in water is presented. Three composite photocatalysts were prepared using silver concentrations of 0.05 mmol, 0.1 mmol, and 0.2 mmol. To evaluate the photocatalytic performance, methylene blue was tested as a preliminary reaction to simulate the degradation of dye compounds. Finally, a comparative analysis between the Ag/TiO2 photocatalyst with the best photocatalytic efficiency versus the TiO2-P25 Degussa without chemical treatment is presented. The results obtained show that all composites present a phase change from anatase to rutile. Photocatalysis experiments showed that Ag(0.05mmol)/TiO2 composite presented 98.9% degradation efficiency in concentrations below 15 mgL−1 of methylene blue and that the degradation efficiency was less than 60.6% in concentrations of 30 mgL−1. On the other hand, the Scanning Electron Microscopy micrographs show that the Ag(0.05mmol)/TiO2 compound does not present significant morphological changes after the degradation process. The fact that Ag(0.05mmol)/TiO2 has not presented significant morphological changes could suggest that it can be reused during the degradation process of organic compounds. The results show that the Ag(0.05mmol)/TiO2 composite obtained by combustion method has the potential to be used in the degradation of dyes mainly present in the textile industry.

Keywords

• Combustion
• Dye degradation
• TiO2 composites
• Titanium oxide
• Silver composites