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以碳氮纳米管(NCNTs)为载体,利用氮的锚定作用,采用三种不同的制备方法(等体积浸渍法、胶体法和沉积沉淀法)方便地构建了负载铁物种的Fe/NCNTs催化剂.系统考察了制备方法对催化剂的结构及费托反应性能的影响.结果表明,制备方法影响铁纳米粒子的粒度和分布、催化剂的还原和碳化行为,使催化剂表现出不同的催化性能.等体积浸渍法得到分散性较好、粒径小和分布窄[(8±4)nm]、容易还原和碳化的催化剂,反应中呈现出最高的低碳烯烃选择性、催化活性和稳定性.胶体法得到了形貌各异的粒子,反应中活性相易被氧化使得催化剂活性及稳定性较差.沉积沉淀法得到了粒径过大、难以还原和碳化的粒子,反应15 h后催化剂活性及稳定性急剧下降.该研究为利用氮掺杂碳纳米材料作为载体设计和开发高性能的费托合成催化剂提供了有益参考.
Using carbon nanotube nanotubes (NCNTs) as carrier, the Fe / NCNTs catalysts supported on iron species were conveniently constructed by three different preparation methods (isostatic impregnation method, colloidal method and sedimentation precipitation method) using the anchoring effect of nitrogen .The influence of preparation method on the structure and Fischer-Tropsch reaction performance of the catalyst was systematically investigated.The results showed that the preparation method affected the particle size and distribution of the iron nanoparticles, the reduction and carbonation behavior of the catalyst, resulting in different catalytic performance of the catalyst. The impregnation method gives the catalysts with good dispersibility, small size and narrow distribution [(8 ± 4) nm], easy reduction and carbonization, and shows the highest selectivity, catalytic activity and stability of light olefins. The particles with different morphologies were obtained, and the active phase was easily oxidized during the reaction, resulting in poor activity and stability of the catalyst.The particles whose particle size was too large to be reduced and carbonized were obtained by the precipitation method.The activity and stability of the catalyst after 15 h reaction This study provides a useful reference for the design and development of high performance Fischer-Tropsch synthesis catalysts using nitrogen-doped carbon nanomaterials as carriers.