Cano-Casanova Laura, Amorós-Pérez Ana, Lillo-Ródenas María Ángeles, Román-Martínez María Del Carmen
MCMA Group, Department of Inorganic Chemistry and Materials Institute, University of Alicante, E-03080 Alicante, Spain.
Materials (Basel). 2018 Nov 9;11(11):2227. doi: 10.3390/ma11112227.
Since the two most commonly used methods for TiO₂ preparation are sol-gel (SG) and hydrothermal (HT) synthesis, this study attempts to compare both methods in order to determine which one is the most suitable to prepare photocatalysts for propene oxidation. In addition, this work studies how the concentration of the HCl used for hydrolysis of the TiO₂ precursor affects the properties of the obtained materials. Also, the effect of avoiding the post-synthesis heat-treatment in a selection of samples is investigated. The photocatalysts are characterized by XRD, N₂ adsorption-desorption isotherms and UV-vis spectroscopy, and the study tries to correlate the properties with the photocatalytic performance of the prepared TiO₂ samples in propene oxidation. TiO₂ materials with high crystallinity, between 67% and 81%, and surface area (up to 134 m²/g) have been obtained both by SG and HT methods. In general, the surface area and pore volume of the TiO₂-HT samples are larger than those of TiO₂-SG ones. The TiO₂-HT catalysts are, in general, more active than TiO₂-SG materials or P25 in the photo-oxidation of propene. The effect of HCl presence during the TiO₂ synthesis and of the post synthesis heat treatment are much more marked in the case of the SG materials.
由于制备二氧化钛最常用的两种方法是溶胶-凝胶法（SG）和水热法（HT），本研究试图比较这两种方法，以确定哪种方法最适合制备用于丙烯氧化的光催化剂。此外，本工作研究了用于水解二氧化钛前驱体的盐酸浓度如何影响所得材料的性能。同时，还研究了在部分样品中避免合成后热处理的效果。通过X射线衍射（XRD）、氮气吸附-脱附等温线和紫外-可见光谱对光催化剂进行了表征，并且该研究试图将这些性能与制备的二氧化钛样品在丙烯氧化中的光催化性能相关联。通过溶胶-凝胶法和水热法均获得了结晶度在67%至81%之间且表面积高达134平方米/克的高结晶度二氧化钛材料。一般来说，水热法制备的二氧化钛样品的表面积和孔体积大于溶胶-凝胶法制备的二氧化钛样品。总体而言，在丙烯的光氧化反应中，水热法制备的二氧化钛催化剂通常比溶胶-凝胶法制备的二氧化钛材料或P25更具活性。在溶胶-凝胶法制备的材料中，合成过程中盐酸的存在以及合成后热处理的影响更为显著。
