AgBr and Ag3PO4 Coupled with TiO2 as Active Powder Photocatalysts and Glass Coatings

In this work, different materials based on TiO2 coupled with either AgBr or Ag3PO4 were synthesized. The Ag3PO4(50%)/TiO2 powder photocatalyst prepared by deposition–precipitation method showed higher antimicrobial activity than the bare TiO2 and also than the same coupled powder obtained by sol–gel method. This material achieved 100% E. coli, coliforms, and other enterobacteria elimination. The high bactericidal efficiency of this material could be attributed to the improved properties obtained by coupling Ag3PO4 and TiO2, such as high absorption in the visible region, low band-gap value, and high surface hydroxylation. The sol–gel method was chosen for the production of photocatalytic coatings on borosilicate glass tubes based on TiO2 and Ag3PO4/TiO2 materials due to the ease of its preparation procedure and its suitability for dip coating. In this series, the most effective elimination of E. coli, coliforms, and other enterobacteria was achieved with the glass tubes coated with the laboratory–prepared TiO2 sol. Interestingly, this material presented superior antimicrobial performance as coating (100% of E. coli elimination) compared to its powder form. The titania coating also showed the best efficiency in the degradation of methylene blue (i.e., 95.2%), though this material lost 30% of its photoactivity after four reaction cycles.