Nanoscaled TiO2/Ag Catalysts and Their Photodecomposition Characteristics

Abstract

The concentration of AgNO 3 plays a significant role in the formation and growth of silver nanoparticles in the preparation of catalysts. When the concentration of AgNO 3 was decreased to 0.2 wt%, flakelike Ag was observed. The corresponding zeta potentials of the TiO 2 solution at pHs of 11, 6.2, and 3 suggest that the electric repulsion between the TiO 2 nanoparticles was very strong in both alkaline and acidic solutions, causing their "effective dispersion." Therefore, a highly dispersed nanostructured TiO 2 /Ag catalyst can be synthesized at a pH of 11 in alkaline solution. Nearly all the dimethyblue target pollutant present at high concentrations was removed when the photoreaction was performed over a short period of time. This novel nano-TiO 2 photocatalyst exhibits excellent photocatalytic activity because it is well-dispersed. In addition, no dispersant or organic binder was used for this synthetic process.