金属-半导体氧化物催化剂

STUDIES ON THE METAL/SEMICONDUCTOR OXIDE CATALYSTS

本文重点研究TiO_2、ZnO、SnO_2等半导体氧化物以及以此为担体的担载型金属-半导体组合催化材料;采用电导、TPD、TPR、TPSR等方法考察了这类材料和典型的电子受体和电子给体反应分子间的电子和物种的交换,并研究了金属-半导体组合界面上的电子传递特性。 根据测试结果及催化反应的例证说明,在金属-半导体氧化物组合材料中金属可以活化反应分子,沟通电荷物种的交换渠道,而氧化物类似于“电子储库”。二者协同作用使组合体系具有良好的氧化还原化学感应和催化作用。

Semiconductor oxides, such as TiO2, ZnO, SnO2, and catalysts with metals supported on them were studied by means of electric conductivity, TPD, TPR and TPSR to explore their charge transfer and species interchange characteristics with reacting molecules acting as electron donors or acceptors. The charge transfer characteristics at the metal-semiconductor interface were also studied. On the basis of the experimental measurements on the various properties of the catalytic systems studied as well as the results on the catalytic model reactions, it was demonstrated that the metal-semiconductor composite materials possess the following feature (See Table 1 ) . Metals, working as the channel for charge and species exchange, can activate the reacting molecules while the semiconductor oxides serve as the 'electron sink and source'.As the result of the synergetic action the composite materials give rise to sensitive chemical response to redox reagents and are often excellent catalysts for the oxidation-reduction reactions.