摘要
本文制备了不同形态的含镍Y沸石,研究了温度,时间和H_2S浓度对含镍Y沸石硫化的影响,发现负载型含镍Y沸石最易硫化,离子交换型次之,骨架型最难硫化.考察了沸石表面硫化物物种的热稳定性和水热稳定性.指出高温下沸石脱附的水蒸汽能使硫化物发生水解,导致催化剂失硫,用XRD,IR和化学分析等方法对硫化的含镍沸石催化剂进行表征,硫化后沸石表面形成的NiS_r有可能是属正交晶系的Ni_7S_6化合物.对噻吩加氢脱硫反应,硫化的含骨架镍Y沸石无催化活性,硫化的离子交换型合镍Y沸石活性比负载型含镍Y沸石高5～6倍左右,因其酸性较强.催化剂表面酸性位和硫化镍活性位共存,对噻吩加氢脱硫反应是有利的.
NaY zeolites containing different types of nickel species were prepared. The effects of temperature, time and H2S concentration on sulfidation of the zeolites were investigated. The NiO impregnated zeolite samples are sulfided most readily, while the isomorphous substituted Ni heteroatom bearing zeolite is the hardest to be sulfided. The thermal and hydrothermal stabilities of the sulfide species formed on the zeolite surface were studied. Water desorbed from the zeolite at elevated temperature may cause the hydrolysis of the sulfides and thus leads to the desulfidation of the catalysts. The sulfided Ni - containing zeolite catalysts were characterized by means of XRD, IR and chemical analysis. The nickel sulfide formed on the zeolites after sulfidation is probably Ni7S6 with an orthorhombic symmetry. Sulfided Ni heteroatom bearing Y zeolite is not active towards thiophene conversion reaction. The hydrodesulfurization activity of the sulfided Ni2+ exchanged zeolites is 5~6 times higher than that of the sulfided NiO impregnated zeolites due to their higher acidity. The coexistence of acid sites and nickel sulfide sites on the zeolite will promote the thiophene hydrodesulfurization reaction significantly.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1996年第9期838-845,共8页
Acta Chimica Sinica
基金
国家基础研究重大项目课题
