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．
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.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2000年第1期35-39,共5页
关键词
硅胶
氧化钒
氧化磷
负载型催化剂
催化活性
silica, vanadium oxide, phosphorus oxide, supported catalyst, adsorption center, lattice oxygen
