摘要
作者用低温溶剂化金属原子浸渍法制备了Fe_n/MgO-200和Fe_n/MgO-400催化剂。两种催化剂的制备过程相同,只是载体MgO的脱羟基温度前者为200℃,后者为400℃。TEM,XRD和CO化学吸附测定结果表明,由于MgO-200比MgO-400表面氢氧根浓度大,二甲苯铁(O)络合物与MgO-200的作用比与MgO-400的作用强,它在MgO-200上的分解速度较快,因而在MgO-200上形成的Fe_n原子簇比在MgO-400上形成的Fe_n颗粒大。Mossbauer谱和O_2化学吸附测定结果还表明,由于MgO-200比MgO-400表面氢氧根浓度大,在MgO-200上形成的Fe_n比在MgO-400上形成的Fe_n带更高的正电荷。基于两种催化剂的分散度和电性质不同,它们在Fischer-Tropsch反应中表现的催化性质也不同。
The solvated metal atom impregnation (SMAI) technique was employed to prepare Fe_n/MgO-200 and Fe_n/MgO-400 catalysts. The support MgO-200 was dehydroxylated at 200℃ and MgO-400 at 400℃. Results of TEM, XRD and CO chemisorption show that the average size of the Fe clusters formed on MgO-200 is larger than that of the Fe clusters on MgO-400. This is because the surface hydroxyl group concentration of MgO-200 is higher that than of MgO-400 and the rate of decomposition of bis-toluene-Fe(O) on MgO-200 is faster than that of bis-toluene-Fe(O) on MgO-400. Mossbauer and O_2 chemisorption measurements indicate that the average charge of Fe_n on MgO-200 is larger than that of Fe_n on MgO-400 as a result of the higher surface hydroxyl group concentration on MgO-200. Owing to the differances in dispersions and electronic properties of the two catalysts, their catalytic properties for Fischer-tropsch reaction are different.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
1990年第2期130-136,共7页
Journal of Fuel Chemistry and Technology
关键词
金属蒸气
溶剂化
金属催化剂
铁
metal vapor synthesis
solvated metal atom
Fe_n cluster
Fiseher-Tropseh recation
