Surface, optical and photocatalytic properties of silica-supported TiO 2 treated with electron beam Pawel Wronski a , Jakub Surmacki a , Halina Abramczyk a , Agnieszka Adamus a , Magdalena Nowosielska b , Waldemar Maniukiewicz b , Marcin Kozanecki c , Magdalena Szadkowska-Nicze a,n a Institute of Applied Radiation Chemistry, The Faculty of Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland b Institute of General and Ecological Chemistry, The Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland c Department of Molecular Physics, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland HIGHLIGHTS  Titanium (IV) n-butoxide and silica were used for synthesis of TiO 2 /SiO 2 samples.  Preparation conditions affected surface and optical properties of TiO 2 /SiO 2 samples.  Electron beam red shifted light absorption of TiO 2 /SiO 2 samples.  Electron beam enhanced the photoactivity of TiO 2 /SiO 2 in azo dye discoloration. article info Article history: Received 1 September 2014 Received in revised form 15 December 2014 Accepted 17 December 2014 Available online 18 December 2014 Keywords: TiO 2 /SiO 2 composites Electron beam irradiation Visible-light-photocatalysis abstract The influence of high-energy electron beam, (EB), treatment, in the dose range of 100–1000 kGy, on the physicochemical properties of silica-supported TiO 2 was examined. TiO 2 /SiO 2 supported oxides were obtained by impregnation of commercial silica gel (2–4 mm) with titanium (IV) n-butoxide. Surface and optical properties of prepared TiO 2 /SiO 2 systems were analyzed using SEM, BET, XRD, Raman and UV–vis spectroscopy. The photoactivity under visible light was tested in discoloration of azo dye solution. No significant structural changes of the TiO 2 /SiO 2 surface were detected as a result of EB treatment. Effect of EB irradiation was observed as an increase of photocatalytic activity in dye decomposition under visible light for TiO 2 /SiO 2 samples containing ca. 23 wt% TiO 2 . The enhancement of activity was assigned to EB- induced defects and C-modification of TiO 2 particles. & 2014 Elsevier Ltd. All rights reserved. 1. Introduction Titanium dioxide is one of the most intensively studied pho- tocatalysts for air and water purification. Practical application of titania creates a need to design a reactor which would maximize photocatalytic efficiency and minimize the energy consumption. The large surface area of the photocatalyst is one of the most important factors in achieving a high efficiency in the photo- catalytic reaction. The photocatalytic activity of TiO 2 tend to be increased when surface area of TiO 2 is larger (Carp et al., 2004). Incorporating the TiO 2 into an adsorbent material, such as silica, has many advantages over using a TiO 2 suspension for water purification. Silica is an unique support because it occurs in many physical forms and chemical compounds, posses large surface area and high porosity and is transparent to the UV radiation. SiO 2 -supported TiO 2 materials have been extensively used as cat- alysts for a wide variety of reactions because their physicochemical properties are superior than those of the single oxides (Kim et al., 2005). Moreover TiO 2 supported on SiO 2 surface is effective on the recovery of photocatalyst. Different types of commercial silica gels (Lepore et al., 1996; Kobayakawa et al., 1998; Yamashita et al., 1998; Chun et al., 2001; Chen et al., 2004; Wang et al., 2006; Qourzal et al., 2009; Bellardita et al., 2010; Bai et al., 2011) were used as matrices for TiO 2 immobilization, and various TiO 2 pre- cursors: titanium alkoxides (Lepore et al., 1996; Bellardita et al., 2010; Jaroenworaluck et al., 2012), titanium chlorides (Kobayaka- wa et al., 1998; Yamashita et al., 1998; Bellardita et al., 2010) or commercial TiO 2 powders (Lepore et al., 1996) were employed to Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/radphyschem Radiation Physics and Chemistry http://dx.doi.org/10.1016/j.radphyschem.2014.12.009 0969-806X/& 2014 Elsevier Ltd. All rights reserved. n Corresponding author. Fax: þ48 42 684 00 43. E-mail address: magdanis@mitr.p.lodz.pl (M. Szadkowska-Nicze). Radiation Physics and Chemistry 109 (2015) 40–47