论文部分内容阅读
通过控制制备过程中的洗涤次数,采用沉淀凝胶法制备了一系列不同钠离子含量的Co/SiO2催化材料,并采用X射线衍射、N2吸脱附、X射线能谱衍射、H2-程序升温还原、透射电镜和原子吸收光谱等多种表征手段系统研究了材料中残留钠离子对Co/SiO2材料的结构、分散性、氧化还原性和形貌的影响.结果表明,残留的钠离子使得样品比表面积下降,平均孔径增大,导致Co3O4的颗粒尺寸迅速增大.同时钠离子对Co3O4的还原具有抑制作用,使得样品的还原难度增大.结果导致Co/SiO2催化材料在乳酸酯加氢反应中的活性大大降低,同时造成丙酸乙酯副产物增加,对1,2-丙二醇(1,2-PDO)选择不利.
A series of Co / SiO2 catalytic materials with different content of sodium ions were prepared by precipitation gel method by controlling the washing times in the preparation process. The effects of X-ray diffraction, N2 adsorption and desorption, X-ray diffraction, H2-temperature programmed Reduction, transmission electron microscopy and atomic absorption spectroscopy were used to characterize the structure, dispersibility, redox properties and morphology of the Co / SiO2 materials. The results show that the residual sodium ions make the sample The specific surface area decreased and the average pore diameter increased, which led to the rapid increase of the particle size of Co3O4. At the same time, the reduction of Co3O4 was restrained by sodium ions, which made the reduction of the sample more difficult. The activity in the reaction is greatly reduced while at the same time increasing the ethyl propionate by-product and adversely affecting 1,2-propanediol (1,2-PDO) selection.