Developing a cost-effective synthesis of active iron oxide doped titania photocatalysts loaded with palladium, platinum or silver nanoparticles

The main aim of this work is to utilize available materials such as ilmenite ore (as a source of titanium and iron oxides) and industrial wastes (as sources of noble metals) for preparation of Fe2O3-TiO2 photocatalysts. A template-free one-step hydrothermal method was applied for synthesis of Fe2O3-TiO2 and its loaded Pd, Pt and Ag nanoparticles. The TEM results indicated that Fe2O3-TiO2 and Pd, Pt and/or Ag nanoparticles, are partly in close contact. TiO2 nanoparticles with an average diameter of about 10 nm are quite uniform in size and shape. Pd, Pt and Ag are well dispersed and exhibit diameters of about 5, 10 and 20 nm respectively. Also, TEM evinces that the framework of the highly crystalline mesoporous Fe2O3-TiO2 is composed of aligned anatase phase grown along the [1 0 1]. The N-2 isotherms of the prepared Fe2O3-TiO2 and its noble metals loaded were characteristic of mesoporous solids. The meso-Fe2O3-TiO2 nanocomposites possess high surface area of 175 m(2) g(-1) and large pore volumes of 0.28 cm(3) g(-1). These values were reduced to 124-145 m(2) g(-1) and 0.18-0.26 cm(3) g(-1), respectively, as a result of loading of noble metals. Photocatalytic degradation of methylene blue (MB) under UV and visible-lights indicated that the meso-Fe2O3-TiO2 exhibited more enhanced activity under UV and visible-lights compared with TiO2 P-25. Addition of Ag to Fe2O3-TiO2 the most promising catalytic activity toward MB degradation under visible light. However, photodegradation of the MB under UV light was enhanced by adding Pd to Fe2O3-TiO2. Utilization of raw ores and spent materials to prepare such photocatalysts represents an attractive approach due to the reduction of the production cost for practical environmental application. (C) 2012 Elsevier B.V. All rights reserved.