铂系金属氧化物对增强Al_2O_3热稳定性作用的研究

Mechanism of Metal Oxide of Pt-Series to Increase Thermal Stability of Al_2O_3 Carrier

为探索铂金属氧化物(以下均用MO_(x)代表)对增强栽体Al_2O_3热稳定性作用的机理,本文采用了氮物理等温吸附、X-射线物相分析、电子探针及附栽催化剂的活性试验等多种方法,研究了Al_2O_3和MO_(x)-Al_2O_3两种物系的物理和化学性质,认为MO_(x)对增强载体Al_2O_3热稳定性的作用,主要是通过MO_(x)与Al_2O_3间存在较强的相互作用、从而提高了Al^(3+)和O^(-2)的扩散活化能,在一定程度上抑制了它们间的互扩散,此外在加热过程中,Al_2O_3晶界间将偏析出MO_(x)晶粒而提高了Al_2O_3晶粒迁移所需越过的能垒,从而形成了Al_2O_3晶粒间的碰撞障碍,有效地防止其进一步的聚集。

In order to explore the mechanism of the metal oxide of Pt-series(MOx) to increase the thermal stability of Al2O3 carrier, in this paper the physical and chemical properties of both the Al2O3 system and the MOx-Al2O3 system are widely investigated by means of N2 isothemal physisorption, XRD, SEM and activity test of supported catalysts, etc. It is pointed out that there is strong interaction between MOx and Al2O3, which will increase the Al+3 and O-2 diffused activation energy and restrain their diffusion. In addition, in heated process, the crystals of MOx will be separated between the crystal surfaces of Al2O3, which will increase the transporting potential barrier of Al2O3-crystals and prevent them further aggregation.