物理化学学报 >> 1985, Vol. 1 >> Issue (03): 281-288.doi: 10.3866/PKU.WHXB19850313

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MoO3-SnO2相互作用的研究

牛春明; 颜其洁; 陈懿   

  1. 南京大学化学系
  • 收稿日期:1984-12-17 修回日期:1985-02-26 发布日期:1985-06-15

A STUDY OF THE INTERACTION BETWEEN MoO3 AND SnO2

Niu Chunming; Yen Qijie; Chen Yi   

  1. Chemistry Department; Nanjing Univcrsity
  • Received:1984-12-17 Revised:1985-02-26 Published:1985-06-15

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摘要： 用沉淀法、浸渍法和机械混合物焙烧法制备了三组MoO_3-SnO_2催化剂。XDR, IR和ESR等研究表明: MoO_3-SnO_2之间存在明显的相互作用, 两组份间发生电子迁移现象, 导致Mo(Ⅵ)→Mo(Ⅴ)的价态变化, 产生pKa≤+3.3的表面酸位和甲醇选择氧化活性位。制备方法对这种相互作用以及样品的催化性能有明显影响。沉淀法所得样品中MoO_3可溶于SnO_2形成固溶体; 浸渍法则可发生钼离子向SnO_2体相的扩散; 机械混合物焙烧法在一定MoO_3含量下, MoO_3可在SnO_2表面形成近似单层分散。红外光谱中950 cm~(-1)的新吸收谱带可归因于表面上Mo(Ⅴ)=0振动。表面Mo(Ⅴ)位可能是催化剂表面酸位和甲醇氧化的活性中心。没有发现催化剂中Sn~(4+)价态有明显变化。

Abstract: MoO_3-SnO_2 catalysts prepared by precipitation, impregnation and high temperature calcination of the relevant mixtures have been investigated by using XRD, IR and ESR, It is shown that there is a strong interaction between MoO_3 and SnO_2. An electron transfer process occurs between two components and leads to the formation of Mo~(5+) from Mo~(6+), surface acid site with pKα≤+3.3 as well as active center for methanol selective oxidation.
The preparation method has significant effect on the interaction between MoO_3 and SnO_2 and the catalytic behavior of the catalysts. MoO_3 can dissolve in SnO_2 forming solid solution in the catalyst prepared by precipitation method, while Mo ions diffuse into the bulk of SnO_2 in hte catalyst prepared by impregnation. Below a certain level, MoO_3 can disperse as a monolayer on the SnO_2 surface in the ctalyst prepared by high temperature calcination.
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