张涛等：nature of active fe species and reaction mechanism over high-efficiency fe/cha catalysts in catalytic decomposition of n2o
发布时间：2020-11-30
abstract:
fe/cha catalysts for n2o decomposition with various fe loadings (fe/sapo-34 and fe/ssz-13) were synthesized by a solid-state ion exchange method. under the same reaction conditions, obviously superior activities of fe/cha catalysts were observed in comparison with the current state-of-the-art fe/zeolite, i.e., fe/fer. meanwhile, fe/cha catalysts exhibited a robust high-temperature hydrothermal stability. the characterization results and density functional theory (dft) calculations indicated that the dispersion of fe species over fe/cha catalysts was strongly influenced by the nature of the support, although sapo-34 and ssz-13 have similar morphology. combined with the catalytic performance, dinuclear [ho-fe-o-fe-oh]2 species were identified as the most active fe species for fe/cha catalysts in the n2o decomposition reaction. furthermore, the dimeric fe species in ssz-13 were more active than those in sapo-34, due to lower fe-o binding energies. finally, dft calculations provided a comprehensive understanding of the n2o decomposition mechanism over fe/cha catalysts.
keywords: n2o decomposition, fe/cha, dispersion, active fe species, mechanism investigation
摘要: 采用固态离子交换法合成了不同铁负载量的fe/cha催化剂(fe/sapo-34和fe/ssz-13)。在相同的反应条件下，与目前最先进的铁基分子筛催化剂，即fe/fer相比，fe/cha催化剂的活性明显更高。同时，fe/cha催化剂表现出良好的高温水热稳定性。表征结果和密度泛函理论(dft)计算表明，尽管sapo-34和ssz-13具有相似的形貌，但铁物种在fe/cha催化剂上的分散受到载体性质的强烈影响。结合催化性能，双核[ho-fe-o-fe-oh]2 物种被确定为n2o分解反应中fe/cha催化剂最活跃的铁物种。此外，由于fe-o结合能较低，ssz-13中的二聚铁比sapo-34中的更活跃。最后，密度泛函理论计算提供了对fe/cha催化剂上n2o分解机理的全面理解。
关键词: n2o分解，fe/cha，分散度，活性fe物种，机理研究
原载于journal of catalysis (sci, q1, 2020 impact factor= 7.888)
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