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V-P-O/SiO2催化剂上表面氧性质的研究
A Study of Surface Properties of V-P-O/SiO2 Catalysts
【摘要】 用浸渍法制备了组成为V2O5∶P2O5∶SiO2 =20∶x∶100(x =0 ~60,质量比)的VPO/SiO2 催化剂,用TPR,IR和TPD法测定了苯和氧在催化剂表面的吸附,在无气相氧和吸附氧存在的条件下用连续TPD 方法测定了苯化学吸附与催化剂表面活性端基氧之间的关系. 发现VPO/SiO2 催化剂对苯的吸附至少有四种吸附中心,但有两种吸附中心是不具有催化活性的,一种对应于苯的物理吸附,而另一种则被CO2 所占据.VPO/SiO2 催化剂表面上氧的吸附随催化剂中P2O5 含量的增加而增加,而苯的化学吸附随催化剂表面活性端基氧的增加而增加.
【Abstract】 V P O/SiO 2 catalysts with V 2O 5∶P 2O 5∶SiO 2=20∶ x ∶100 ( x =0~60, mass ratio) were prepared by impregnation method and the adsorption properties of benzene and oxygen on these catalysts were investigated through TPR, IR and TPD methods. The chemical adsorption properties of benzene in the absence of gaseous or adsorbed oxygen during the continuous TPD tests were also studied. It is found that there are at least four kinds of adsorption sites on the surface of V P O/SiO 2, among which, two (one related with physical adsorption and the other occupied by CO 2 produced in the catalyst preparation) are catalytic inactive. The adsorption of oxygen on the catalysts increases with the increase of P 2O 5 content, while the chemical adsorption of benzene increases with the increase of active lattice oxygen of VO.
【Key words】 silica; vanadium oxide; phosphorus oxide; supported catalyst; adsorption center; lattice oxygen;
- 【文献出处】 催化学报 ,CHINESE JOURNAL OF CATALYSIS , 编辑部邮箱 ,2000年01期
- 【分类号】O643.36
- 【被引频次】8
- 【下载频次】112