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利用氢气在较低温度(623 K)下对6%Mo/HZSM-5催化剂进行预处理,考察了经低温还原预处理的催化剂在甲烷无氧芳构化反应中的催化性能.结果表明,经过预处理的催化剂比未经预处理的催化剂表现出更好的甲烷转化活性和稳定性.1HMAS NMR和EPR表征结果表明,在623 K氢气气氛中对Mo/HZSM-5催化剂进行预处理不会造成Mo物种在分子筛外表面的进一步分散,也不会导致外表面的Mo物种向孔道内迁移.但是,低温还原预处理可以有效地促进Mo物种由易还原的六方密堆积结构向难还原的面心立方结构转化,后者在反应中具有更好的活性和稳定性.
Hydrogen was used to pretreat 6% Mo / HZSM-5 catalyst at lower temperature (623 K) to investigate the catalytic performance of the catalyst pretreated with low temperature reduction in anaerobic methane aromatization reaction. The pretreatment catalyst showed better methane conversion activity and stability than the non pretreatment catalyst.HMAS NMR and EPR characterization results showed that pretreatment of Mo / HZSM-5 catalyst in 623 K hydrogen atmosphere would not result in The further dispersion of Mo species on the outer surface of the molecular sieve does not lead to the migration of Mo species on the outer surface into the pore, however, pretreatment with low temperature reduction can effectively promote the reduction of Mo species from the easily reducible hexagonal close packed structure to the hard to reduce Cubic structure transformation, the latter in the reaction has better activity and stability.