Improved Visible-light Photocatalytic Activity of Bi-crystalline Mesoporous Titania Codoped with Carbon and Silver

A bi-crystalline mesoporous titania (meso-TiO 2 ) with anatase and rutile composite nanocrystal frameworks was prepared and then modified by carbon doping (C-meso-TiO 2 ), silver nanoparticle loading (Ag-meso-TiO 2 ), and carbon-silver codoping (Ag-C-meso-TiO 2 ). The visible-light photocatalytic activities of the samples were evaluated by the degeneration of aqueous methylene blue (MB) solution under visible-light irradiation (wavelength >420 nm). The prepared bi-crystalline mesoporous samples showed obviously higher visible-light photocatalytic activity than that of the commercial anatase titania nanoparticles (NPs). Ag-C-meso-TiO 2 exhibited the highest visible-light photocatalytic activity which could be attributed to the band gap narrowed by the doped carbon and the plasmon electron transfer from Ag NPs to the titania matrix, and the corresponding MB degeneration rate reached 65% after 180 min visible-light irradiation while that of the commercial titania NPs just reached 7%.