摘要
随着石油资源的日益枯竭及环保要求的日益严苛,寻找非石油路线生产清洁燃料的方法迫在眉睫,费-托合成是一种以合成气(CO和H_2)为原料生产液体燃料的高效方法.铁基费-托合成催化剂广泛应用于工业,本工作研究了多孔碳材料包裹的活性组分高度分散的铁基费托催化剂的制备、结构及费-托合成反应性能.以金属有机骨架材料Fe-MIL-100为前驱体,通过控制碳化温度调节催化剂金属负载量、催化剂粒子尺寸及铁的相态.研究发现碳化温度为500℃所得催化剂在反应温度为260℃、压力为3 MPa、空速为8000 h^(-1)时CO转化率达到68%,展现出优良的中温费托合成反应性能.
Depletion of crude oil resources and environmental concerns have spurred worldwide interest in finding un-oil route for liquid fuels. Fischer-Tropsch synthesis is an effective progress for a wide spectrum of hydrocarbon chains from synthesis gas. The use of iron-based catalysts would be preferred in the industry. Here we present a strategy to produce highly dispersed active component embedded in a matrix of porous carbon. Through the carbonization of iron-containing metal- organic frameworks （Fe-MIL-100） at different temperature in N2, four kinds of Fe@C catalysts were prepared. Glucose was used as additional carbon precursor for the synthesis catalyst samples to prevent particle agglomeration. Our strategy avoids the particle agglomeration in the weak metal-support interaction Fe@C catalysts during calcination, reduction and reaction. The structure and morphology of prepared catalysts were characterized by X-ray diffraction （XRD）, N2 physical adsorption, transmission electron microscopy （TEM）, inductively coupled plasma-atomic emission spectrometer （ICP-AES）. It is demon- strated that the iron loading, the particle size, and the Fe phase structure of Fe@C catalysts can be controlled by changing the carbonization temperature of Fe-MIL-100. With increasing the temperature, the iron loading and the particle size increase gradually. Depending on the carbonization temperature, the Fe3O4 phase is dominant at 400 and 500 ℃. The FeO and Fe phase appear at 600 ℃. The Fe3C phase prevails at 700℃. The high dispersion of the metal phase and its encapsulation in a highly porous carbon matrix result in an unrivalled FTS activity. The spatial restriction created by encapsulation seems to minimize sintering and oxidation of the active Hagg carbide phase. When the reaction conditions were set at 260 ℃, 3 MPa, the space velocity of 8000 h-1, the conversion of CO is up to 68%. The Fe time yield （FTY） of the Fe@C-500 catalyst were as high as 164 μmolCO.gFe-1.s-1, which surpasses that of most F-T catalysts reported in the literature in middle-temperature Fischer-Tropsch synthesis.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2017年第4期360-366,共7页
Acta Chimica Sinica
基金
国家自然科学基金重大研究计划项目(No.91545109)
山西省国际科技合作项目(No.2014081004)资助~~
