%0 Journal Article
%T Sol-Gel Synthesized Semiconductor Oxides in Photocatalytic Degradation of Phenol
%A Maria K. Cherepivska
%A Roman V. Prihod¡¯ko
%J ISRN Physical Chemistry
%D 2014
%R 10.1155/2014/724095
%X Effectiveness of photocatalytic degradation of phenol in aqueous solution using semiconductor oxides (SO) prepared by a sol-gel method was examined. The physical and chemical properties of synthesized catalysts were investigated by X-ray diffraction (XRD), diffuse reflectance UV-Vis spectroscopy (DRS), and N2-adsorption measurements. The optimal conditions of the photocatalytic degradation of phenol using prepared titanium dioxide sample were defined. 1. Introduction Heterogeneous photocatalysis on the semiconductors allows achieving complete mineralization of the various classes toxic and biorefractory organic substances [1, 2]. Recently, the photocatalytic degradation of toxicants became one of the most promising directions of ¡°green chemistry¡± [3]. The use of nanosized SO presents a great interest due to their outstanding optical, magnetic, catalytic, and sensing properties [4, 5]. The phenolic compounds contained in the wastewater of chemical, petrochemical, and pharmaceutical industries are hazardous carcinogenic and mutagenic pollutants [6, 7]. Furthermore, the oxidation of these substances in water bodies leads to decrease in dissolved oxygen required for normal functioning of animals and plants. Finding effective methods for the protection of water systems from phenols contamination is an important aim to ensure environmental safety [8, 9]. Among SO photocatalysts (PC) high activity have Fe2O3, WO3, ZnO and TiO2. Iron oxide polymorphs of hematite (¦Á-Fe2O3) are nontoxic, cheap, and stable to photocorrosion material intensively absorbs radiation in the range from 295 to 600£¿nm. The semiconductor properties of ¦Á-Fe2O3 are the same as WO3, which can be seen in the position of band gaps relative to the standard hydrogen electrode. WO3 has chemical stability in acidic medium and electrolyte solutions as well as photoactivity in the near ultraviolet and blue regions of solar spectrum [10]. According to Daneshvar et al. nanosized ZnO is a suitable alternative to TiO2 due to the band gap energy. Dinda and Icli found that ZnO was as reactive as TiO2 for the photocatalytic degradation of phenol under concentrated sunlight [11]. Figure 1 shows a scheme of the energy levels of the studied semiconductor oxides relative to the standard hydrogen potential [12]. Several authors have associated the efficiency of semiconductor photocatalysts with electronic, structural, and morphological properties of the material such as band gap energy, crystalline structure, surface area, particle size [13]. Figure 1: Energy band gap of investigated semiconductor oxides. The
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