以空心SiO2为载体的蛋壳型贵金属Pd催化剂的制备及表征

以空心SiO₂为载体采用浸渍法制备了一系列蛋壳型贵金属Pd催化剂和Ca-Pd 催化剂，应用TEM，XRD和EDS方法表征催化剂。结果表明，贵金属Pd不仅能够负载到空心SiO₂载体上，分散也比较均匀，且粒径较小，Pd/SiO₂催化剂上Pd的粒径约为7 nm，Ca-Pd/SiO₂催化剂上Pd的粒径约为5 nm。在蛋壳型催化剂Pd/SiO₂ 中加入助催化剂Ca能够形成蛋壳型Ca-Pd复合催化剂。空心SiO₂可以作为蛋壳型贵金属Pd催化剂载体。催化活性评价结果表明，蛋壳型复合催化剂Ca-Pd/SiO₂的催化活性和甲醇的选择性较纯Pd催化剂有了较大幅度的提高，其中催化活性提高了7倍。

Preparation and characterization of eggshell Pd catalysts supported on hollow silica

A series of eggshell monometallic palladium catalysts and bimetallic Ca-Pd catalysts supported on hollow silica have been prepared by the impregnation method. The eggshell catalysts were characterized by TEM, XRD and EDS. The results showed that Pd particles are supported on the hollow silica support. The Pd metal particle sizes of the Pd/SiO₂ catalyst and Ca-Pd/SiO₂ catalyst were 7 nm and 5 nm, respectively,. with all the particles well dispersed on the support. The EDS results showed that eggshell bimetallic Ca-Pd/SiO₂ catalysts can be prepared when co-catalyst Ca was added to the Pd catalyst Pd/SiO₂, and confirming that the hollow silica can be used as support for eggshell Pd catalysts. Catalytic tests with H₂/CO mixtures showed that the activity and selectivity to methanol of the eggshell catalyst Ca-Pd/SiO₂ were higher than those of the pure Pd catalyst. The activity of Ca-Pd/SiO₂ was 17.88 mmol?mol^-1?s^-1, which was about 7 times larger than that of the pure Pd catalyst.