Ag nanoparticles supported on wormhole HMS material as catalysts for CO oxidation: Effects of preparation methods
Ag nanoparticles supported on wormhole HMS material as catalysts for CO oxidation: Effects of preparation methods
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DOI：
10.1016/j.powtec.2012.07.031
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发表时间：
2012-11
影响因子：
5.2
通讯作者：
Xiaodong Zhang;Z. Qu;Jingxuan Jia;Yi Wang
中科院分区：
文献类型：
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作者：
Xiaodong Zhang;Z. Qu;Jingxuan Jia;Yi Wang
采用原位还原法（后组装法和原位掺入法）制备了以蠕虫孔HMS为载体的银纳米粒子。采用XRD、N2吸附-脱附、ICP-AES和TEM等手段对催化剂进行了表征。结果表明，制备方法对HMS的结构和Ag颗粒的大小有很大的影响。由于还原过程中DDA的保护作用，原位掺入法（在最后一步中向混合溶液中加入正硅酸乙酯）得到了粒径最小（4.5nm）的银纳米粒子。同时，溶液中的甲醛会与DDA发生反应，导致样品的结构有序度降低，BET值降低。在后组装方法中，DDA与无机Si物种之间的氢键削弱了DDA对银物种的亲和力，导致银纳米颗粒在随后的还原过程中聚集。研究了催化剂对CO低温氧化反应的催化活性。除了银纳米颗粒的尺寸效应外，据信样品的结构有序性对于高催化活性也是至关重要的。
Ag nanoparticles supported on wormhole HMS material were prepared by in-situ reduction methods (post-assembly and in-situ incorporation methods). The catalysts were characterized by XRD, N2adsorption–desorption, ICP-AES and TEM. It was found that the preparation methods strongly affected the structure of HMS and Ag particle size. Due to the protection of DDA in the reduction process, Ag nanoparticles with smallest size (4.5nm) were obtained in in-situ incorporation method (TEOS was added into the mixture solution in the last procedure). Meanwhile, HCHO in the solution can react with DDA, resulting in the decrease of structural order and BET value of the sample. In post-assembly methods, the H-bonding between DDA and the inorganic Si species weakens the affinity of DDA for Ag species, resulting in the aggregation of Ag nanoparticles in the following reduction process. The catalytic activity of catalysts for low-temperature CO oxidation was studied here. Besides the size effect of Ag nanoparticles, it was believed that the structural order of the samples was also crucial for high catalytic activity.