Determination of the rate limiting step in the oxidation of CO on Pt(111) surfaces

被引：35

作者：

Liu, J ^{[1
]}

Xu, M ^{[1
]}

Zaera, F ^{[1
]}

机构：

[1] TSING HUA UNIV,DEPT CHEM,BEIJING 100084,PEOPLES R CHINA

来源：

CATALYSIS LETTERS | 1996年 / 37卷 / 1-2期

关键词：

CO oxidation; surface kinetics;

D O I：

10.1007/BF00813512

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The kinetic behavior of the oxidation of carbon monoxide on Pt(111) was studied at different temperatures by exposing both oxygen-covered surfaces to molecular CO beams and clean surfaces to CO + O-2 mixed beams under ultra-high vacuum (UHV) conditions. Results from the first type of experiments show that on oxygen-covered surfaces the rate for CO2 production above 400 K is determined by the impinging rate of the carbon monoxide molecules. On clean surfaces the oxidation rate is equally determined by the CO incoming flux as long as the CO : O-2 ratio in the CO + O-2 mixed beams is low. For high CO : O-2 ratios, however, the CO steady-state coverage increases, poisoning the adsorption of oxygen, and slowing down the overall CO2 production. The rate of surface recombination of CO with oxygen also competes with that of CO adsorption at low temperatures, giving rise to a fairly complex overall dynamic behavior.

引用

页码：9 / 13

页数：5

共 21 条

[1] FAST REACTION-PRODUCTS FROM THE OXIDATION OF CO ON PT(111) - ANGULAR AND VELOCITY DISTRIBUTIONS OF THE CO2 PRODUCT MOLECULES [J].