摘要
采用浸渍法和干混法制备了一系列负载钼的层柱分子筛催化剂 (Mo/Al-CLM )以及负载钼的γ -Al2 O3催化剂 (Mo/γ -Al2 O3)。利用XRD分析了样品表面上钼的分散性。结果发现 ,两种催化剂无论是浸渍法合成还是干混法合成 ,均可以使催化剂中钼在载体表面上自发分散而使晶相钼物种消失 ,而钼含量高时 ,催化剂表面上保留晶相钼物种。而且无论是浸渍法还是干混法合成的催化剂 ,相同钼含量时 ,均是Mo/γ -Al2 O3催化剂表面上钼的分散性优于Mo/Al-CLM催化剂。通过氨水处理 ,可以使低、中以及高钼含量的催化剂上所有晶相钼物种消失 ,即溶解掉一部分表面钼物种 。
Mo/Al-CLM and Mo/γ-Al2O3 catalysts were prepared by impregnation or heating mixture method. The dispersion of MoO3 or APM on the surface of Al-CLM and γ-Al2O3 was determined by X-ray diffraction (XRD). The results show that the XRD peaks of MoO3 or APM crystalline disappear if the Mo loading is low in the two catalysts prepared by impregnation or heating mixture method, and if the Mo loading is high, the XRD peaks of Mo species appear. Meanwhile, the dispersion property of Mo species on the surface of γ - Al2O3 is better than that of Al - CLM catalyst when their Mo contents are the same. Ammonia extraction could dissolve Mo crystalline and a portion of no-active dispersed Mo species in Mo/Al - CLM and Mo/γ - Al2O3 catalysts and the dispersion property of Mo species can be thus improved.
出处
《石油化工高等学校学报》
EI
CAS
2001年第3期1-6,31,共7页
Journal of Petrochemical Universities
基金
国家自然科学基金资助项目 ( 2 96730 0 1 )
