Zr-doped TiO2 nano photocatalyst obtained with a various trace amount of Zr, by using the sol-gel method. Several spectroscopic techniques applied to characterize the structures and properties of nanophotocatalyst. It founded that the effect of doping Zr ions to the TiO2 lattice led it to improve the surface properties and decreasing the particle size of nano-photocatalyst. Therefore, it causes increasing specific surface area and photocatalytic activity as compared with pure TiO2. The results revealed that there was an inverse relationship between the growth of the crystallite size of the nano photocatalyst and the decline of the molar ratios of Zr. The photocatalytic activity of the nano photocatalyst employed for the decolorization of Congo red as an Azo dye in the aqueous solution under UV irradiation in a batch reactor. The results exhibited that the TiO2/Zr0.0004 brings the best photocatalytic activity.
Keywords:TiO2/Zr Nanocomposite; Decolorization; Sol-Gel; UV Irradiation; Congo Red; Spectroscopic Techniques.
Article History:
Received: 05 February 2018Accepted: 24 May 2018
1-IntroductionOne of the most important sources of environmental contamination is dye pollution. Heterogeneous photocatalysis is an interesting method employed for the thorough removal of pollution under solar or artificial light irradiation [1-2]. TiO2 based photocatalysis enjoys such advantages as low cost, non-toxicity and chemical stability, making it as a good choice for the efficient oxidization and degradation of dye pollutants [3]. It has been shown that photon absorption of anatase TiO2 is only limited to the UV range due to its large band gap (3.2ev) [2]. A good way to improve photocatalytic activity is through the incorporation of dopant into TiO2 lattices, introducing additional energy levels and defects into the microstructure of the TiO2 [4]. There are different modification techniques to reduce band gap; these include doping with noble metals like Au, Ag and Pt [5-9], non-precious metals such as Fe, Cu, Cr, Mn, W, Ru, Ni, Sb [10][11][12][13][14], oxides such as ZnO,ZrO2, and non-metallic elements like N, C, S, F and P [17][18][19]. Zirconium ions, which act as a kind of dopant in TiO2, have been found to modify the photocatalytic activity and stabilization of anatase phase at high temperatures [20][21][22]. Many different methods have been proposed for the preparation of Zr-doped TiO2 nanocomposites; these are such as mechanochemical doping, co-precipitation, chemical vapor deposition and sol-gel methods. However, it must be noted that most of the above-mentioned techniques are time consuming and require expensive equipment. The sol-gel method has the unique advantage that it can synthesize at low temperature, under high purity and easily controlled reaction condition [23][24], its simplicity and possibility of the synthesis of nano photocatalyst at low temperature with high purity [25]. Recently, according to properties of Zr, TiO2 was used with specific molar ratios of Zr for different applications [26].In this...
