Deposition of Palladium Nanodots of Controlled Size and Density onto Surface‐Modified SiO2 Particles by an Atmospheric Pressure CVS/MOCVD Process
Deposition of Palladium Nanodots of Controlled Size and Density onto Surface‐Modified SiO2 Particles by an Atmospheric Pressure CVS/MOCVD Process
复制标题
通过大气压 CVS/MOCVD 工艺将尺寸和密度受控的钯纳米点沉积到表面改性的 SiO2 颗粒上
DOI：
10.1002/cvde.200606543
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发表时间：
2007
影响因子：
--
通讯作者：
G. Kasper
中科院分区：
文献类型：
--
作者：
A. Binder;A. Heel;G. Kasper
描述并表征了常压下连续气相法制备Pd/SiO2催化剂颗粒的工艺。重点研究了载体粒子表面钯纳米点的大小和数量密度的控制。在第一步中，在流动反应器中通过化学气相合成（CVS）从四乙基（邻位）硅酸盐（TEOS）连续生成亚微米大小的SiO2载体颗粒。本文介绍了一种工艺集成的方法，通过调整合成条件，使SiO2表面羟基的浓度在1 ~ 6个OH / nm2之间变化。第二步，通过Cp（烯丙基）Pd [（η3-烯丙基）（η5-环戊二烯基）钯]的金属有机（MO）CVD将Pd纳米点沉积在SiO2上。通过调节气相前驱体浓度，Pd纳米点的中位直径在1.3 ~ 3 nm （σg ~ 1.2）之间变化。结果表明，在每100 nm2载体颗粒表面0 ~ 12个Pd岛的范围内，Pd岛的数量密度与SiO2上羟基的密度成正比变化。
A continuous gas-phase process under atmospheric pressure for tailoring Pd/SiO2 catalyst particles is described and characterized. Emphasis is placed on controlling the size and number density of Pd nanodots on the surface of the carrier particle. In the first step, sub-micrometer-sized SiO2 support particles are generated continuously in a flow reactor by chemical vapor synthesis (CVS) from tetraethyl(ortho)silicate (TEOS). A process-integrated method is described to vary the surface concentration of hydroxyl groups on the SiO2 between about 1 and 6 OH groups per nm2, by adjusting the synthesis conditions. In a second step, Pd nanodots are deposited onto the SiO2 by metal–organic (MO)CVD of Cp(allyl)Pd [(η3-allyl)(η5-cyclopentadienyl)palladium]. The median diameter of the Pd nanodots was varied between about 1.3 and 3 nm (σg ∼1.2) by adjusting the precursor concentration in the gas phase. It is shown that the number density of the Pd islands varied in proportion to the density of hydroxyl groups on the SiO2 in the range 0-12 Pd islands per 100 nm2 of carrier particle surface.