Chemical and structural effects of strontium on iron-based Fischer-Tropsch synthesis catalysts
Chemical and structural effects of strontium on iron-based Fischer-Tropsch synthesis catalysts
复制标题
锶对铁基费托合成催化剂的化学和结构影响
DOI：
10.1016/j.mcat.2018.01.037
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发表时间：
2018-04-01
影响因子：
4.6
通讯作者：
Li, Yongwang
中科院分区：
文献类型：
--
作者：
Li, Jifan;Hou, Yifeng;Li, Yongwang
采用一系列不同锶铁摩尔比的Fe/SiO_2催化剂，考察了锶对铁基F-T合成(FTS)催化剂的化学和结构的影响。结果表明，锶的化学作用增强了Fe_2O_3的Fe-O键，从而抑制了氧化铁的还原。化学效应也抑制了H-2的吸附，但促进了CO的吸附，这是低表面H/C比和甲烷选择性的原因。同时，锶的促进改善了铁氧化物的分散性。分散效应促进了催化剂的还原和碳化。它还有利于H-2的吸附，进而导致高的表面H/C比和甲烷选择性。在化学效应和结构效应的共同作用下，催化剂对甲烷的选择性随锶负载量呈抛物线变化，在锶铁摩尔比为6/100时达到最低。相反，重烃的选择性表现出相反的趋势。
A series of Fe/SiO2 catalysts with different strontium/iron molar ratios were used to investigate the chemical and structural effects of strontium on the iron-based Fischer-Tropsch synthesis (FTS) catalysts. It was found that the chemical effect of strontium strengthened Fe-O bonds of Fe2O3 and hence suppressed the reduction of iron oxide. The chemical effect also suppressed the H-2 adsorption but improved the CO adsorption, which is responsible for the low surface H/C ratios and methane selectivity. At the same time, the promotion of strontium improved the dispersion of iron oxides. The dispersion effect facilitated the reduction and carburization of catalysts. It was also helpful for the H-2 adsorption and in turn led to high surface H/C ratios and methane selectivity. Under the combined action of the chemical and structural effects, the selectivity to methane of catalysts exhibited a parabola-like trend as a function of strontium loading and passed through a minimum at Sr/Fe molar ratio of 6/100. In contrast, the selectivity of heavy hydrocarbon demonstrated an opposite tendency.