Critical influence of the amorphous silica-to-cristobalite phase transition on the performance of Mn/Na2WO4/SiO2 catalysts for the oxidative coupling of methane

被引:229
作者
Palermo, A
Vazquez, JPH
Lee, AF
Tikhov, MS
Lambert, RM
机构
[1] Univ Cambridge, Dept Chem, Cambridge CB2 1EW, England
[2] Univ Mar del Plata, Inst Mat Sci & Technol, CONICET, RA-7600 Mar Del Plata, Argentina
[3] Univ Sevilla, CSIC, Inst Ciencia Mat, Seville 41092, Spain
关键词
OCM; oxidative coupling of methane; phase transition; support interaction;
D O I
10.1006/jcat.1998.2109
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
XRD, XPS/XAES, TPR analysis and catalytic testing have been applied to Na/W/Mn/SiO2 methane coupling catalysts and to corresponding formulations without one or more of Na, Mn, and W. We find a clear correlation between catalyst performance and support structure in the final calcined material. Amorphous silica yields active but very unselective catalysts. Crystalline SiO2 (alpha-cristobalite) generates active and highly selective catalysts-especially with respect to the formation of ethylene. We demonstrate that the presence of Na is essential for the anomalous low temperature silica --> cristobalite support phase transition to occur. The structural, catalytic, and spectroscopic results indicate that Na plays a dual role as both structural and chemical promoter. (C) 1998 Academic Press.
引用
收藏
页码:259 / 266
页数:8
相关论文
共 15 条
  • [1] CONVERSION OF METHANE BY OXIDATIVE COUPLING
    AMENOMIYA, Y
    BIRSS, VI
    GOLEDZINOWSKI, M
    GALUSZKA, J
    SANGER, AR
    [J]. CATALYSIS REVIEWS-SCIENCE AND ENGINEERING, 1990, 32 (03): : 163 - 227
  • [2] ANDERSON JR, 1989, APPL CATAL, V47, P177, DOI 10.1016/S0166-9834(00)83227-3
  • [3] Fang X., 1992, J MOL CATALYSIS CHIN, V6, P427
  • [4] METHANE TO ETHYLENE WITH 85-PERCENT YIELD IN A GAS RECYCLE ELECTROCATALYTIC REACTOR-SEPARATOR
    JIANG, Y
    YENTEKAKIS, IV
    VAYENAS, CG
    [J]. SCIENCE, 1994, 264 (5165) : 1563 - 1566
  • [5] OXIDE SUPPORT INTERACTION AND SURFACE RECONSTRUCTION IN THE NA2WO4/SIO2 SYSTEM
    JIANG, ZC
    YU, CJ
    FANG, XP
    LI, SB
    WANG, HL
    [J]. JOURNAL OF PHYSICAL CHEMISTRY, 1993, 97 (49) : 12870 - 12875
  • [6] THE OXIDATIVE CONVERSION OF METHANE TO HIGHER HYDROCARBONS OVER ALKALI-PROMOTED MN/SIO2
    JONES, CA
    LEONARD, JJ
    SOFRANKO, JA
    [J]. JOURNAL OF CATALYSIS, 1987, 103 (02) : 311 - 319
  • [7] SYNTHESIS OF ETHYLENE VIA OXIDATIVE COUPLING OF METHANE .1. DETERMINATION OF ACTIVE CATALYSTS
    KELLER, GE
    BHASIN, MM
    [J]. JOURNAL OF CATALYSIS, 1982, 73 (01) : 9 - 19
  • [8] OXIDATIVE COUPLING OF METHANE TO HIGHER HYDROCARBONS
    LEE, JS
    OYAMA, ST
    [J]. CATALYSIS REVIEWS-SCIENCE AND ENGINEERING, 1988, 30 (02): : 249 - 280
  • [9] Lunsford J.H., 1990, CATAL TODAY, V6, P235
  • [10] QIU X, 1993, J CHEM TECH BIOTECHN, V65, P303