IN-SITU ELLIPSOMETRIC STUDY OF A PALLADIUM CATALYST DURING THE OXIDATION OF METHANE

被引:66
作者
KONI, D [1 ]
WEBER, WH [1 ]
POINDEXTER, BD [1 ]
MCBRIDE, JR [1 ]
GRAHAM, GW [1 ]
OTTO, K [1 ]
机构
[1] FORD MOTOR CO,FORD RES LAB,MD 3028,SRL,DEARBORN,MI 48121
关键词
ELLIPSOMETRY; METHANE; PALLADIUM; PALLADIUM OXIDE; OSCILLATIONS;
D O I
10.1007/BF00807112
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
Ellipsometry is used to follow the growth of a PdO layer on the surface of a thick Pd-film catalyst during methane oxidation at approximately 500-degrees-C. The oxide layer that develops under rich conditions (excess CH4) is quite porous and roughnes with time. Little CO is formed during this period, but the CO2 formation rate increases until spontaneous oscillations develop, which correlate with changes in the ellipsometric data. These changes indicate that the porous oxide rapidly converts to a metal-rich state, which has decreased catalytic activity, and then slowly reoxidizes.
引用
收藏
页码:329 / 338
页数:10
相关论文
共 22 条
[1]   HIGH PRECISION SCANNING ELLIPSOMETER [J].
ASPNES, DE ;
STUDNA, AA .
APPLIED OPTICS, 1975, 14 (01) :220-228
[2]   OPTICAL-PROPERTIES OF THIN-FILMS [J].
ASPNES, DE .
THIN SOLID FILMS, 1982, 89 (03) :249-262
[3]   CATALYTIC COMBUSTION OF METHANE OVER SUPPORTED PALLADIUM CATALYSTS .2. SUPPORT AND POSSIBLE MORPHOLOGICAL EFFECTS [J].
BALDWIN, TR ;
BURCH, R .
APPLIED CATALYSIS, 1990, 66 (02) :359-381
[4]   CATALYTIC-OXIDATION OF METHANE OVER PALLADIUM SUPPORTED ON ALUMINA - EFFECT OF AGING UNDER REACTANTS [J].
BRIOT, P ;
PRIMET, M .
APPLIED CATALYSIS, 1991, 68 (1-2) :301-314
[5]  
BRUGGEMAN DAG, 1935, ANN PHYS-LEIPZIG, V24, P313
[6]   AUTOMATIC ROTATING ELEMENT ELLIPSOMETERS - CALIBRATION, OPERATION, AND REAL-TIME APPLICATIONS [J].
COLLINS, RW .
REVIEW OF SCIENTIFIC INSTRUMENTS, 1990, 61 (08) :2029-2062
[7]   OXIDATION OF METHANE OVER SUPPORTED PRECIOUS METAL-CATALYSTS [J].
CULLIS, CF ;
WILLATT, BM .
JOURNAL OF CATALYSIS, 1983, 83 (02) :267-285
[8]   OSCILLATORY KINETICS AND SPATIOTEMPORAL SELF-ORGANIZATION IN REACTIONS AT SOLID-SURFACES [J].
ERTL, G .
SCIENCE, 1991, 254 (5039) :1750-1755
[9]   CATALYTIC CHEMISTRY OF SUPPORTED PALLADIUM FOR COMBUSTION OF METHANE [J].
FARRAUTO, RJ ;
HOBSON, MC ;
KENNELLY, T ;
WATERMAN, EM .
APPLIED CATALYSIS A-GENERAL, 1992, 81 (02) :227-237
[10]   EFFECT OF CATALYST STRUCTURE ON METHANE OXIDATION OVER PALLADIUM ON ALUMINA [J].
HICKS, RF ;
QI, HH ;
YOUNG, ML ;
LEE, RG .
JOURNAL OF CATALYSIS, 1990, 122 (02) :295-306