TRANSIENT AND ISOTOPIC STUDIES OF THE OXYGEN-TRANSPORT AND EXCHANGE DURING OXIDATIVE COUPLING OF METHANE ON SR PROMOTED LA2O3

被引:48
作者
KALENIK, Z
WOLF, EE
机构
[1] Department of Chemical Engineering, University of Notre Dame, Notre Dame, In
关键词
OXIDATIVE COUPLING OF METHANE; LA2O3; ISOTOPIC EXCHANGE;
D O I
10.1007/BF00764836
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
Isotopic transient techniques were applied to study oxidative coupling of methane over lanthanum oxide and strontium promoted La2O3 catalysts. Results of the O-18(2)/O-16(2) isotopic exchange experiments indicate that Sr promotion increases oxygen uptake from the lattice of the catalyst. Oxygen self diffusion coefficients, which were determined for the series of lanthana catalysts, reach a maximum for the 1% Sr/La2O3. Steps of O-18(2) in the presence of a steady flow of methane over Sr/La2O3 catalysts, indicate that surface and bulk oxygen appear in the reaction products before gas-phase O-18(2). Steps of CO2 over catalysts in which lattice oxygen has been exchanged with O-18(2), show that gas/solid exchange involves over 50% of the lattice oxygen. Under reaction conditions, methane pulses with no gas-phase oxygen yield negligible amounts of products which indicates that methane interacts with lattice oxygen only in the presence of the gas-phase oxygen.
引用
收藏
页码:441 / 449
页数:9
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