Alumina-promoted sulfated mesoporous zirconia catalysts

Chi Chau Hwang, Chung Yuan Mou

研究成果: 雜誌貢獻文章同行評審

32 引文 斯高帕斯(Scopus)

摘要

Mesoporous zirconia, hydrothermally synthesized from surfactant templating, was directly impregnated with aluminum sulfate to give the acidic Al-promoted sulfated mesoporous zirconia (AS/MP-ZrO2). A series of AS/MP-ZrO 2 catalysts were characterized by Brunauer-Emmett-Teller and X-ray diffraction for their texture properties and crystalline phases. The catalytic behavior for n-butane isomerization was found to be strongly promoted at relatively low temperature by the addition of a proper amount of alumina as a promoter. 27Al S.S. magic-angle spinning nuclear magnetic resonance results indicated that Zr atoms were partially substituted by Al, giving a considerable increased concentration of Brønsted acids. X-ray photoelectron spectroscopy and diffuse-reflectance infrared Fourier-transformed spectra (DRIFT) analysis were then employed to identify and relatively quantify properties of acid sites on catalyst surface. A balanced distribution of acid sites strength was proven to prevent a catalyst from deactivating rapidly due to coke formation on the catalyst surface. A small concentration of olefins formed by oxidation of n-butane and proven to be key intermediates during n-butane isomerization on sulfated zirconia was found by the Baeyer test. Electron paramagnetic resonance and in situ DRIFT results show that this occurs via oxidative dehydrogenation of butane by the sulfate groups to form butene which leads to butyl carbenium species for skeleton isomerization. A modified biomolecular mechanism for the isomerization of butane is examined to explain the catalysis results.

原文英語
頁(從 - 到)5212-5221
頁數10
期刊Journal of Physical Chemistry C
113
發行號13
DOIs
出版狀態已發佈 - 4月 2 2009
對外發佈

ASJC Scopus subject areas

  • 電子、光磁材料
  • 能源(全部)
  • 物理與理論化學
  • 表面、塗料和薄膜

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