Catalytic and photocatalytic 2-propanol dehydration was carried out by using a supported Keggin heteropolyacid H₃PW₁₂O₄₀ (PW₁₂). Binary materials were prepared by impregnation and/or solvothermal treatment by using commercial supports: SiO₂ (Mallinckrodt), TiO₂ (Evonik P25) and multiwall carbon nanotubes (Sunnano) or home solvothermically prepared SiO₂ and TiO₂. All the materials have been characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with EDX microanalysis, specific surface area measurements, diffuse reflectance spectroscopy (DRS), FTIR and Raman spectroscopy. (Photo)catalytic 2-propanol dehydration was studied in gas-solid regime by using a continuous (photo)reactor working at atmospheric pressure and 80°C. FTIR spectra of the gas-phase over the PW₁₂-support composites, where 2-propanol had been previously adsorbed, were recorded. Propene and diisopropyl ether were the main reaction products. For the continuous photo-assisted runs the reactor was also illuminated with UV light. The apparent activation energy of 2-propanol catalytic and photocatalytic dehydration was determined in the range 60–120°C. The irradiance increased significantly the dehydration reaction rate. Important differences were observed between the different supported materials. The Keggin heteropolyacid species played a key role both for the catalytic and the photo-assisted catalytic reactions; in fact, the acidity of the cluster accounts for the catalytic role, whereas both the acidity of the cluster and the oxidant ability of PW₁₂ were responsible for the increase of the reaction rate of the photo-assisted catalytic reaction. Moreover, the photo-generated electrons on the solid semiconductor conduction band can account for a further increase of the reaction rate, when the heteropolyacid was supported on TiO₂. Formation of a pseudo-liquid phase played an important role to determine the (photo)activity.

中文翻译：

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用于气固状态下2-丙醇（光辅助）催化脱水的负载型H3PW12O40：载体和假液相在（光）活性中的作用

通过使用负载的Keggin杂多酸H ₃ PW ₁₂ O ₄₀（PW ₁₂）进行催化和光催化的2-丙醇脱水。二元材料是通过使用商业载体进行浸渍和/或溶剂热处理制得的：SiO ₂（Mallinckrodt），TiO ₂（Evonik P25）和多壁碳纳米管（Sunnano）或自制的热解法制备的SiO ₂和TiO ₂。所有材料的特征均在于X射线衍射（XRD），扫描电子显微镜观察（SEM）以及EDX显微分析，比表面积测量，漫反射光谱（DRS），FTIR和拉曼光谱。通过使用在大气压力和80°C下工作的连续（光）反应器，在气固状态下研究了（光）催化2-丙醇的脱水反应。PW _12上气相的FTIR光谱记录了先前已吸附了2-丙醇的β-载体复合材料。丙烯和二异丙醚是主要反应产物。对于连续的光辅助运行，反应器也用紫外线照射。在60–120°C范围内确定了2-丙醇催化和光催化脱水的表观活化能。辐照度显着提高了脱水反应速率。在不同的支撑材料之间观察到重要差异。Keggin杂多酸物质在催化和光辅助催化反应中都起着关键作用。实际上，簇的酸度起催化作用，而簇的酸度和PW ₁₂的氧化能力负责光辅助催化反应的反应速率的增加。此外，当将杂多酸负载在TiO ₂上时，在固体半导体导带上的光生电子可以说明反应速率的进一步提高。假液相的形成对确定（光）活性起重要作用。