Solar photocatalytic and electrokinetic studies of TiO_2/Ag nanoparticle suspensions

摘要

Composites of TiO_2 and Ag nanoparticles were used to study photodegradation of aqueous Rhodamine B under natural sunlight exposure. The addition of Ag powder resulted in a ～45% increase of the photocatalytic activity of TiO_2 after 30 min, which is attributed to the suppression of the photo-generated electron-hole pair recombination. Electrokinetic studies on TiO_2, Ag, and TiO_2/Ag aqueous solutions address the question of how the electron transfer occurs. It was found that the TiO_2 and TiO_2/Ag zeta potential versus pH behavior is virtually identical which suggests that the Ag particles are encapsulated by the TiO_2 particles, allowing the electron transfer across the 'static' semiconductor-metal interface.