论文部分内容阅读
以Al2O3为载体,采用沉积沉淀法制备了无铬环境友好型Cu-ZnO-MnOx/Al2O3催化剂,并用于α,α-二甲基苄醇氢解制异丙苯研究.利用X射线粉末衍射(XRD)、低温N2吸附、扫描电镜(SEM)、X荧光光谱仪(XRF)等表征及活性评价手段考察了沉淀pH值、沉淀温度、老化时间和焙烧温度对催化剂物化性质及催化性能的影响.试验结果表明,沉淀温度主要影响前驱体中各物相的转化速率;沉淀pH值和老化时间不仅影响前躯体中各物相的转变速度而且影响Cu2+、Zn2+的同晶取代速率;焙烧温度则主要影响前躯体的分解和催化剂的晶粒大小,前躯体中(Cu0.3Zn0.7)5(CO3)2(OH)6和(CuZn)2CO3(OH)2是CuO-ZnO固溶体的主要物相,而(Cu0.3Zn0.7)5(CO3)2(OH)6物相的形成有利于提高催化剂的稳定性.
A chromium-free environment-friendly Cu-ZnO-MnOx / Al2O3 catalyst was prepared by deposition precipitation method using Al2O3 as carrier and was used for the hydrogenation of cumene by α, α-dimethylbenzyl alcohol.Using X-ray powder diffraction XRD, X-ray photoelectron spectroscopy (XRF) and X-ray fluorescence spectroscopy (XRF) were used to investigate the effects of pH value, precipitation temperature, aging time and calcination temperature on the physico-chemical properties and catalytic performance of the catalyst. The results show that the precipitation temperature mainly affects the conversion rate of each phase in the precursor. The precipitation pH value and aging time affect not only the transformation speed of each phase in the precursor but also the isomorphous substitution rate of Cu2 + and Zn2 +, and the calcination temperature Precursor decomposition and catalyst grain size, Cu (Cu0.3Zn0.7) 5 (CO3) 2 (OH) 6 and (CuZn) 2CO3 (OH) 2 are the main phases of CuO- The formation of (Cu0.3Zn0.7) 5 (CO3) 2 (OH) 6 phase helps to improve the stability of the catalyst.