Ceria on silica and alumina catalysts: dispersion and surface acid-base properties as probed by X-ray diffractometry, UV-Vis diffuse reflectance and in situ IR absorption studies

M.I. Zaki; G.A.M. Hussein; S.A.A. Mansour; H.M. Ismail; G.A.H. Mekhemer

doi:10.1016/S0927-7757(96)03943-X

$Ceria on silica and alumina catalysts: dispersion and surface acid-base properties as probed by X-ray diffractometry, UV-Vis diffuse reflectance and in situ IR absorption studies$

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Ceria on silica and alumina catalysts: dispersion and surface acid-base properties as probed by X-ray diffractometry, UV-Vis diffuse reflectance and in situ IR absorption studies

M.I. Zaki, G.A.M. Hussein, S.A.A. Mansour, H.M. Ismail and G.A.H. Mekhemer

Colloids and surfaces. A, Physicochemical and engineering aspects, Vol.127(1), pp.47-56

02/07/1997

DOI: https://doi.org/10.1016/S0927-7757(96)03943-X

Abstract

Ceria

Ceria on alumina

Ceria on silica

Dispersion

In-situ IR spectroscopy of adsorbed pyridine and CDCl 3

Surface acid properties

Surface base properties

X-ray diffractometry and UV-Vis diffuse reflectance spectroscopy revealed that fluorite-structured CeO 2 crystallites (mean size 22.3 nm) are dispersed on silica surfaces (CeSi) into microcrystallites (11.2-8.1 nm) and dispersed further on alumina surfaces (CeAl) into nanocrystallites (< 8.5 nm) and CeO x monolayers. Consequently, IR spectroscopy of adsorbed pyridine found Lewis acid sites to be far more strengthened on CeAl. Bronsted acid sites (proton-donors) were probed exclusively on CeAl. On the other hand, IR spectroscopy of adsorbed deuterated chloroform (CDCl 3) showed the originally moderate Lewis base sites (low-coordinated OH − and O 2−) to be weakened on CeSi, but markedly strengthened on CeAl. Lewis base sites exposed on ceria surfaces assume a strong nucleophilic reactivity.

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Title: Ceria on silica and alumina catalysts: dispersion and surface acid-base properties as probed by X-ray diffractometry, UV-Vis diffuse reflectance and in situ IR absorption studies
Creators - without role: M.I. Zaki - Kuwait University
G.A.M. Hussein - Minia University
S.A.A. Mansour - Minia University
H.M. Ismail - Minia University
G.A.H. Mekhemer - Minia University
Publication Details: Colloids and surfaces. A, Physicochemical and engineering aspects, Vol.127(1), pp.47-56
Publisher: Elsevier B.V
Identifiers: 9915425708331
Academic Unit: Imam Abdulrahman Bin Faisal University
Language: English
Resource Type: Journal article