Atmospheric-pressure cold plasma for synthesizing Ag modified Degussa P25 with visible light activity using dielectric barrier discharge

Atmospheric-pressure cold plasma was employed to fabricate Ag/TiO2 visible light photocatalyst. UV-vis, XPS and XRD spectra were used to investigate Ag valence in the Ag/TiO2 samples. UV-vis spectra indicated that metal Ag nanoparticles were present after plasma treatment, and the surface plasmon peak became narrower and shifted to shorter wavelengths when the discharge voltage was increased. XPS and XRD spectra proved that Ag ions were completely reduced to metallic Ag nanoparticles. The morphologies of the Ag/TiO2 samples were observed by transmission electron microscopy (TEM). TEM micrographs of the Ag/TiO2 sample fabricated at 36 kV showed that the average particle size of Ag nanoparticles was ca. 7.4 nm. Photocatalytic activity of the Ag/TiO2 samples was evaluated by photodegradation of methylene blue (MB) under visible light (lambda > 420 nm). Compared with Degussa P25, the Ag/TiO2 catalyst fabricated by DBD cold plasma exhibited a high activity for MB degradation. Atmospheric-pressure DBD cold plasma was highly efficient for preparation of supported metallic Ag catalyst. (C) 2013 Elsevier B.V. All rights reserved.