Synthesis of high surface area TiO2 nanoparticles by mild acid treatment with HCl or HI for photocatalytic propene oxidation

Abstract

Elsevier Ouzzine, M.; Maciá Agulló, JA.; Lillo-Ródenas, MA.; Quijada Tomás, C.; Linares-Solano, A. (2014). Synthesis of high surface area TiO2 nanoparticles by mild acid treatment with HCl or HI for photocatalytic propene oxidation. Applied Catalysis B: Environmental. 154-155:285-293. doi:10.1016/j.apcatb.2014 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Page 1 Page 4 of 34A c c e p t e d M a n u s c r i p t Abstract Nanostructured TiO 2 photocatalysts with small crystalline sizes have been synthesized by sol-gel using the amphiphilic triblock copolymer Pluronic P123 as template. A new synthesis route, based on the treatment of TiO 2 xerogels with acid-ethanol mixtures in two different steps, synthesis and extraction-crystallization, has been investigated, analyzing two acids, hydrochloric and hydriodic acid. As reference, samples have also been prepared by extraction-crystallization in ethanol, being these TiO 2 materials amorphous and presenting higher porosities. The prepared materials present different degrees of crystallinity depending on the experimental conditions used. In general, these materials exhibit high surface areas, with an important contribution of microporosity and mesoporosity, and with very small size anatase crystals, ranging from 5 to 7 nm.The activity of the obtained photocatalysts has been assessed in the oxidation of propene in gas phase at low concentration (100 ppmv) under a UVA lamp with 365 nm wavelength. In the conditions studied, these photocatalysts show different activities in the oxidation of propene which do not depend on their surface areas, but on their crystallinity and band gap energies, being sample prepared with HCl both during synthesis and in extraction-crystallizations steps, the most active one, with superior performance than Evonik P25.

Alcohol solvents evaporation-induced self-assembly synthesis of mesoporous TiO2−x−y C x N y nanoparticles toward visible-light driven photocatalytic activity

“…10b) can be used to evaluate the band gaps of the synthetic samples which are indirect semiconductors. As a result, their (Das et al 2010;Ouzzine et al 2014) indicated that higher surface area of TiO 2 improves the absorption of more water molecules on the surface and the higher crystalline but smaller particle size results in an efficient utilization of charge carriers, while the photogenerated carriers diffuse rapidly to the surface and reacts quickly with the adsorbed water molecules. As can be seen in Fig.…”

The use of transient electrolysis in the technology of oxide composite nanostructured materials: review

“…Initially, fluoroplastic (type F-3MV, F-32LN) and silicone varnishes (type KO-85) were investigated as a transparent layer by Bespalova et al [44]. The most promising of them was the 1 -3 mass% solution of F-32LN fluoroplastic varnish.…”

“…Nanostructured coatings based on titanium oxide were obtained as a result of electrophoretic deposition under the influence of an asymmetrical alternating current [16]. This method also has a number of advantages compared to other widely-used nanocrystal titanium dioxide methods [40][41][42][43][44][45]. It should be noted that the use of an asymmetric alternating current for these purposes allowed suppression of gas bubble formation due to the absence of electrolysis of water on electrodes, and obviated the need for using organic stabilizers in the electrolyte-suspension.…”

Effect of Aging Time on the Synthesis of Fe-doped TiO2 Thin Films by Spin Coating Method

“…It is well known TiO2 nanoparticles with good physico-chemical properties are mainly dominated by three phasesnamely anatase, rutile and brookite. On a nanometer scale or in a thin layer form,TiO 2 nanoparticles are transparent and have a wide surface area [3]. To improve the performance of thin film TiO 2 for photovoltaics application purpose such as dye sensitized solar cell, TiO 2 layer has been modified by the addingmetal dopant such as Fe [4] and Zn [5].…”