UV-resistant hydrophobic rutile titania aerogels synthesized through a nonalkoxide ambient pressure drying process
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The hydrophobic rutile titania aerogels were successfully prepared by nonalkoxide ambient pressure drying through a modification process. The resulted materials were characterized by x-ray diffraction, scanning electronic microscope, transmission electron microscope, contact angle analyzer, Brunauer–Emmett–Teller specific surface area, and ultraviolet (UV)–visible diffuse reflection spectrum. The experimental results demonstrated that the as-prepared samples nanoparticles with rutile crystalline structure were uniformly distributed. The UV-resistant hydrophobic samples having high surface area were used as photocatalysts for dye degradation reaction. I. INTRODUCTION
Titanium dioxide has been used as catalyst in photocatalytic reactions because of its high catalytic activity and stability.1 In particular, it has been accepted that titania with a large surface area and small particle size is desirable for photocatalytic reaction. The photocatalytic activity was dependent on the surface area of the catalysts with the higher the surface area and the higher the photocatalytic activity.2 So far, many efforts have been concentrated on the synthesis of photocatalysts in a high surface area form like aerogels. As well known, aerogels are a class of nanostructured materials with high porosity, low density, and high surface area and have only recently begun to be studied for structural applications such as very efficient catalysts and catalytic supports,3 nuclear waste treatment,4 and adsorption materials.5 In the present study, aerogels were prepared by sol–gel method combined with supercritical drying to avoid collapse of the original gel structure due to surface tension. However, it is still a challenge of preparing aerogels on a large scale at low cost. Many researchers have devoted themselves to reduce the cost of aerogel synthesis. In brief, there are two strategies. Schwertfeger et al.6 and Shen et al.7 first concerned the cheap precursors such as sodium silicate, polyethoxydisiloxane (E-40), rice hull, oil ash. Meanwhile, Prakash et al.8 and Rao et al.9 involved a novel drying techniques at ambient pressure instead of supercritical drying. This process may replace the more costly and dangerous operation of supercritical drying. The objective of the research was to find low-cost synthesis conditions to obtain the titania aerogels of better photocatalytic. In this paper, the titania aerogels were obtained by nonalkoxide sol–gel routes and drying under ambient pressure conditions. We also studied the
photocatalytic degradation of dye over titania aerogels under light irradiation and applied to the different systems, which consists of photodegradation and adsorption. Furthermore, the as-prepared titania aerogels exhibited excellent hydrophobicity and durability under ultraviolet (UV) light irradiation. II. EXPERIMENTS A. Preparation of the titania aerogels
All chemicals used were analytical grade and used without further purification. TiCl4 as a nonalkoxide precursor and propylene oxide (PO) as a gelation agent were used for n
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