摘要
使用原位穆斯堡尔谱和微型反应器考察了物相、锰含量和制备方法对Fe-Mn/AC催化剂F-T反应性的影响,并讨论了Fe-Mn/AC催化剂的表面结构及其与F-T反应性的关系。对于Fe-Mn/AC催化剂,将铁还原到金属态时具有很高的活性和对气态烯烃和高碳烃的选择性,锰含量对催化剂的活性和选择性影响不大;影响催化剂选择性的主要是受制备制约的铁-锰在活性炭载体表面的结构形态,对此我们提出了模型,只有当铁-锰处于高分散状态,作为助剂锰才能改善催化剂对气态烯烃和高碳烃的选择性,否则锰反而起不利的作用。
In-situ Mossbauer spectroscopy and microreactor techniques were used to investigate the influences of the chemical states of the iron and manganese components, the content of manganese oxide promoters as well as the methods of catalyst preparation on the Fischer-Tropsch(F-T) reactivities of the iron-manganese/activated carbon (AC) catalysts. Correlations between the F-T reactivities and the surface structures of the iron and manganese components were also discussed.
Experimental results showed that for the Fe-Mn/AC catalysts, high activity and selectivity to light olefins and liquid hydrocarbons were attained when the iron component was reduced to the metallic state, while the content of the manganese oxide promoter was found to be insignificant on the catalytic properties of the catalysts. The main factor influencing the selectivities of the catalysts was the surface structures of iron and manganese oxides on the carbon supports,which in turn depended on the methods of catalyst preparation. Only when the iron and manganese oxide were both highly dispersed on the carbon supports could the manganese oxide act as a promoter and enhance the selectivities of the catalysts to form lower olefins and liquid hydrocarbons. Otherwise, adverse effccts occurred to the selectivities of the catalysts.Surface structure models were proposed to explain these observations.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
1992年第1期1-7,共7页
Journal of Fuel Chemistry and Technology
基金
国家自然科学基金
关键词
铁-锰/活性炭
催化剂
费-托合成
iron-manganese/activated carbon catalysts
Fischer-Tropsch synthesis
Mossbauer spectroscopy
