沸石
材料科学
煅烧
纳米团簇
化学工程
催化作用
结晶
金属
分子筛
烧结
透射电子显微镜
选择性
纳米技术
化学
有机化学
复合材料
冶金
工程类
作者
Xiaoli Yang,Qinggang Liu,Yaru Zhang,Xiong Su,Yanqiang Huang,Tao Zhang
出处
期刊:Nanoscale
[The Royal Society of Chemistry]
日期:2018-01-01
卷期号:10 (24): 11320-11327
被引量:26
摘要
We report here a facile strategy for encapsulating Pt clusters into MFI crystals via a dry gel conversion (DGC) method, by introducing Pt-immobilized Schiff-SiO2 as the silicon resource. This protocol involves a solid phase transformation process for crystallization which occurs without significant deconstruction of the structure of the Pt-containing precursor. High-angle annular dark-field scanning transmission electron microscopy images indicate that most of the Pt clusters are less than 1 nm in size and located in defective channels or voids of MFI. Thanks to the encapsulation role, these Pt clusters are stable against sintering even after calcination at 500 °C and only grow up to ∼2.8 nm after calcination at 800 °C. The uniform pore structure of a zeolite endows the Pt@zeolite catalyst with shape-selectivity for hydrogenation and oxidation reactions over size differentiated analog substrates. This synthesis method is attainable for the embedment of stable metal clusters inside the small-pore MFI zeolite.
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