Titania Surface Modification with Cerium Species for Wastewater Treatment
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Titania Surface Modification with Cerium Species for Wastewater Treatment A. Atyaoui • E. M. M. Sutter • L. Bousselmi
Received: 9 January 2013 / Accepted: 17 April 2013 / Published online: 26 April 2013 Ó Springer Science+Business Media New York 2013
Abstract The electrochemical deposition by a drastic potentiostatic procedure (by applying -2.2 V for 20 min) in cerium (IV) acid solution was used to deposit ceriumcontaining species on titan surface prepared by an anodic oxidation method at 120 V. Their morphologies and structures have been investigated by scanning electron microscopy and X-ray diffraction. The photoelectrochemical characteristics of the electrodes were investigated in methanol and 0.1 M NaOH. The result shows that doping titania with an appropriate amount of Ce can effectively improve its photocatalytic activity, and the optimum doping concentration is found to be relating to the first deposition (0.6 at.% of cerium (IV)) in our experiments. Keywords Titanium oxide Photocatalysis Cerium Electrodeposition Photocurrent
1 Introduction In recent years, TiO2 photocatalysis has been extensively studied due to its potential application for complete mineralization of many toxic and non-biodegradable organic
A. Atyaoui (&) L. Bousselmi Laboratoire de Traitement des Eaux Use´es, Centre de Recherches et Technologies des Eaux, BP. 273 8020 Soliman, Tunisia e-mail: [email protected] L. Bousselmi e-mail: [email protected] A. Atyaoui E. M. M. Sutter LISE, UPR 15 du CNRS, Universite´ Pierre et Marie Curie, Case 133, 4 Place Jussieu, 75252 Paris Cedex 05, France e-mail: [email protected]
pollutants [1, 2], under ultraviolet light (UV) because of its large band gap (Eg = 3.2 eV); but there is only about 3–4 % of UV in sunlight [3]. So, modification of TiO2 is necessary to enhance it’s efficiency under solar or visible light [4, 5]. In order to decrease the bandgap of parent titania photocatalyst (Eg = 3.2 eV), slow down the recombination rate of the e-/h? pairs and enhance interfacial charge transfer efficiency, many methods have been developed, including transition metals doping [6], coupling with other semiconductors [7], noble metals deposition [8] and rare earth ions doping [9]. Lanthanide ions are known for their ability to form complexes with various Lewis bases (e.g., amines, aldehydes, alcohols, thiols, etc.) in the interaction of these functional groups with the f-orbitals of lanthanides [10]. Therefore, it is expected that deposition of lanthanide species on TiO2 provides a way to concentrate the organic pollutants at the semiconductor surface and therefore enhance the photocatalytic activity of TiO2. Rare earth ions doped TiO2 catalysts were prepared by the sol–gel method [11], hydrothermal process [12], coprecipitation- peptization method [13], a one-step solvothermal synthesis, the homogeneous precipitation [14] and the electrochemical deposition (ECD) [15, 16]. The latter method (ECD) is regarded as an inexpensive and easy method to synthesize material. However, ther
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