Preparation of silica-coated Pt metal nanoparticles using microemulsion and their catalytic performance
Preparation of silica-coated Pt metal nanoparticles using microemulsion and their catalytic performance
复制标题
微乳液制备二氧化硅包覆Pt金属纳米粒子及其催化性能
DOI：
10.1016/j.stam.2006.09.013
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发表时间：
2006
影响因子：
5.5
通讯作者：
M. Kishida
中科院分区：
文献类型：
--
作者：
Kunio Hori;H. Matsune;S. Takenaka;M. Kishida
采用油包水型微乳液制备了pt - sio2催化剂。催化剂的制备方法是在含Pt的微乳液中水解四乙基硅酸盐，然后在空气中煅烧，再用h2还原。这种制备Pt - sio2的方法提供了直径约为6 nm的金属铂纳米颗粒均匀覆盖在二氧化硅层上，而传统的浸渍方法则形成了支撑在二氧化硅表面的金属铂颗粒。二氧化硅包覆Pt催化剂（coat-Pt）对二氧化硅负载Pt催化剂（impp -Pt）的混合碳氢化合物的竞争氧化表现出不同的催化性能，即在甲烷和异丁烷的竞争氧化中，涂层Pt催化剂优先氧化甲烷，而异丁烷则选择性氧化impp -Pt催化剂。Ar在涂层- pt上的吸附结果表明，涂层- pt中的二氧化硅具有孔径< 1 nm的多孔结构。由于包裹Pt金属颗粒的二氧化硅多孔结构控制了反应物分子的扩散速率，涂层-Pt对竞争氧化表现出特定的催化性能。
Pt–SiO 2 catalysts were prepared by using water-in-oil type microemulsion. The catalysts were prepared by hydrolysis of tetraethylorthosilicate in the microemulsion containing Pt species, followed by calcination in air and reduction with H 2. This preparation method for Pt–SiO 2 provided Pt metal nanoparticles with a diameter of ca. 6 nm covered uniformly with silica layers, while a conventional impregnation method formed Pt metal particles supported on the silica surface. The Pt catalysts coated with silica (coat-Pt) showed different catalytic performance for the competitive oxidation of mixed hydrocarbons from Pt catalysts supported on silica (imp-Pt), ie in the competitive oxidation of methane and iso-butane, coat-Pt catalysts preferentially oxidized methane, while iso-butane was oxidized selectively over imp-Pt catalysts. The results of the adsorption of Ar on coat-Pt showed that silica in coat-Pt had porous structures of pore diameters< 1 nm. Because the porous structure of silica, which wrapped Pt metal particles, controlled the diffusion rate of reactant molecules, coat-Pt showed a specific catalytic performance for competitive oxidation.