V2O5/TiO2 Catalyst Xerogels: Method of Preparation and Characterization
V2O5/TiO2 Catalyst Xerogels: Method of Preparation and Characterization
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V2O5/TiO2 催化剂干凝胶：制备方法和表征
DOI：
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发表时间：
2002
期刊：
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通讯作者：
A. O. Florentino
中科院分区：
文献类型：
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作者：
C. Rodella;R. W. Franco;C. Magon;J. Donoso;L. Nunes;M. Saeki;M. Aegerter;A. O. Florentino
本文介绍了一种改进的溶胶-凝胶法制备V2O5/TiO2催化剂的方法。用氮气吸附、x射线衍射（XRD）、扫描电镜（SEM/EDX）和傅里叶变换红外光谱（FT-IR）对样品进行了表征。随着钒负载的增加，表面面积从纯TiO2的24 m2 g−1增加到9wt % V2O5的87 m2 g−1。纯TiO2以金红石相为主，随着钒负荷的增加，锐钛矿相逐渐富集。在催化剂的衍射图中未观察到V2O5结晶相。扫描电镜分析表明，颗粒呈非均匀粒状，具有较高的钒分散性。用红外光谱法观察到两种表面钒：单体钒基和聚合钒酸盐。钒基/钒酸盐的比率几乎保持不变。在350 ~ 560k的温度范围内，采用乙醇氧化法进行催化实验。催化活性在380k左右开始。对于含有9wt %钒的样品，在473 K时，乙醇转化为乙醛的主要产物约为90%。
This work describes a modified sol-gel method for the preparation of V2O5/TiO2 catalysts. The samples have been characterized by N2 adsorption at 77 K, X-ray Diffractometry (XRD), Scanning Electronic Microscopy (SEM/EDX) and Fourier Transform Infrared Spectroscopy (FT-IR). The surface area increases with the vanadia loading from 24 m2 g−1 for pure TiO2 to 87 m2 g−1 for 9 wt% of V2O5. The rutile form is predominant for pure TiO2 but becomes enriched with anatase phase when vanadia loading is increased. No crystalline V2O5 phase was observed in the diffractograms of the catalysts. Analysis by SEM showed heterogeneous granulation of particles with high vanadium dispersion. Two species of surface vanadium were observed by FT-IR spectroscopy: a monomeric vanadyl and polymeric vanadates. The vanadyl/vanadate ratio remains practically constant. Ethanol oxidation was used as a catalytic test in a temperature range from 350 to 560 K. The catalytic activity starts around 380 K. For the sample with 9 wt% of vanadia, the conversion of ethanol into acetaldehyde as the main product was approximately 90% at 473 K.