Influence of tungsten precursors on the structure and catalytic properties of WO3/SBA-15 in the selective oxidation of cyclopentene to glutaraldehyde
Influence of tungsten precursors on the structure and catalytic properties of WO3/SBA-15 in the selective oxidation of cyclopentene to glutaraldehyde
复制标题
钨前驱体对WO3/SBA-15环戊烯选择性氧化制戊二醛结构和催化性能的影响
DOI：
10.1021/jp710409g
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发表时间：
2008-03-13
影响因子：
3.7
通讯作者：
Fan, Kangnian
中科院分区：
文献类型：
--
作者：
Yang, Xin-Li;Gao, Ruihua;Fan, Kangnian
以各种钨为原料，采用常规湿浸法制备了介孔WO3/SBA-15。研究了不同钨前驱体对WO3/SBA-15结构的影响及其对环戊烯（CPE）选择性氧化制戊二醛（GA）的催化性能。采用x射线衍射（XRD）、透射电子显微镜（TEM）、紫外-可见漫反射光谱（DRS）、傅里叶变换红外光谱（FT-IR）、x射线光电子能谱（XPS）、程序升温解吸（NH3-TPD）和程序升温还原（H-2-TPR）对钨的色散和性质进行了系统表征。在不同的钨源中，由钨酸与草酸反应生成的钨配合物源WO3的分散性最高，表面Bronsted和Lewis酸性能最强，与SBA-15载体的相互作用最强。结果表明，该催化剂具有较高的CPE转化率和优良的GA选择性。而由仲钨酸铵制备的催化剂由于表面存在WO3晶体而表现出最低的活性。由钨酸与草酸反应制备的催化剂在第一次循环后，由于有少量活性钨种被浸出，其活性略有下降，但经过热处理易于再生后，其活性基本保持不变，说明WO3/SBA-15催化剂在目标反应中属于非均相催化剂。
Mesoporous WO3/SBA-15 was synthesized by the conventional incipient wetness impregnation method from various tungsten precursors. The influence of different tungsten precursors on the structure Of WO3/SBA-15, as well as their catalytic performance for the selective oxidation of cyclopentene (CPE) to glutaraldehyde (GA), was investigated. The dispersion and nature of the tungsten species were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectra (DRS), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (NH3-TPD), and temperature-programmed reduction (H-2-TPR). Among the different tungsten sources, the tungstenic complex sources produced from the reaction of tungstic acid with oxalic acid showed the highest dispersion Of WO3 species, the strongest surface Bronsted and Lewis acid properties, and the strongest interaction with the SBA-15 support. As a consequence, this catalyst gave much higher CPE conversion and excellent GA selectivity. On the other hand, the catalyst prepared from the ammonium paratungstate showed the lowest activity owing to the presence of crystalline WO3 on the surface. Although the activity of the catalyst prepared from the reaction of tungstic acid with oxalic acid decreased slightly after the first recycle due to leaching of small amounts of active tungsten species, it remained nearly the same value after easy regeneration with heat treatment, demonstrating that the WO3/SBA-15 catalyst is a heterogeneous one in the target reaction.