HPW/SiO_2介孔催化剂的合成及其催化性能研究

Synthesis and Catalytic Properties of HPW/SiO_2 Mesoporous Catalyst

以正硅酸乙酯和磷钨酸为主剂,乙醇为溶剂,采用酸碱对自调整的方法合成了介孔HPW/SiO2复合材料。该方法的主要特点是利用HPW自身的酸性来催化正硅酸乙酯的水解,正硅酸乙酯水解后形成带正电荷的有机硅,其与HPW阴离子通过静电作用形成Si-HPW聚集体。随着溶剂的挥发,这些Si-HPW聚集体通过有机无机界面组装形成有序的介观结构,使得Keggin结构杂多酸被固载在SiO2骨架上。通过XRD、透射电镜、氮气吸附和红外光谱等手段表征了其结构。该催化剂在二苯并噻吩的氧化脱硫反应中显示了良好的催化活性和重复使用性能。

Mesoporous phosphotungstic acid/SiO2(HPW/SiO2) composite is synthesized by acid-base pair self-adjustment method.The main strategy of this method is to utilize the acidity self-generated of phosphotungstic acid(HPW) as the catalyst for tetraethoxysilane hydrolysis.The TEOS hydrolysis leads to form the positive charge silicate species that can combine with HPW anion to form colloidal Si-HPW entities resulting from the static interaction.These Si-HPW entities can be assembled to form mesostructure with solvent evaporation,leading Keggin-type heteropolyacids encapsulated into SiO2 framework.The component and structure of composition are characterized by XRD,TEM,nitrogen adsorption-desorption and Fourier transform infrared spectrometer methods.The composite has the excellent catalytic activities and reusing properties in the oxidative desulphurization of bulky molecule dibenzothiophen.