Characterization by ammonia adsorption microcalorimetry of substantially amorphous or partially crystalline ZSM-5 materials and correlation with catalytic activity

C. P. Nicolaides; H. H. Kung; N. P. Makgoba; N. P. Sincadu; M. S. Scurrell

doi:10.1016/S0926-860X(01)00706-2

Characterization by ammonia adsorption microcalorimetry of substantially amorphous or partially crystalline ZSM-5 materials and correlation with catalytic activity

C. P. Nicolaides^*, H. H. Kung, N. P. Makgoba, N. P. Sincadu, M. S. Scurrell

^*Corresponding author for this work

Chemical and Biological Engineering

Research output: Contribution to journal › Article › peer-review

22 Scopus citations

Abstract

Ammonia adsorption microcalorimetry studies have shown that for ZSM-5-based materials, whose XRD crystallinity was varied from 3 to 70%, the number of strong Brønsted acid sites, that is those with a ΔH_ads between 120 and 140 kJ/mol, increases with increasing XRD crystallinity. A strong correlation was observed between the catalytic activity of these zeolite-based materials in terms of the demanding n-hexane cracking reaction and the number of strong acid sites. For samples with XRD crystallinities below 30%, however, the number of strong acid sites is disproportionately low and the catalytic activity only becomes significant at crystallinities above this level.

Original language	English (US)
Pages (from-to)	29-33
Number of pages	5
Journal	Applied Catalysis A: General
Volume	223
Issue number	1-2
DOIs	https://doi.org/10.1016/S0926-860X(01)00706-2
State	Published - 2002

Keywords

Aluminosilicate
Ammonia adsorption microcalorimetry
Brønsted acid
Cracking
NAS catalysts
Zeolite

ASJC Scopus subject areas

Catalysis
Process Chemistry and Technology

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10.1016/S0926-860X(01)00706-2

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@article{73a446a1ee5d4388a379730e3c3526d5,

title = "Characterization by ammonia adsorption microcalorimetry of substantially amorphous or partially crystalline ZSM-5 materials and correlation with catalytic activity",

abstract = "Ammonia adsorption microcalorimetry studies have shown that for ZSM-5-based materials, whose XRD crystallinity was varied from 3 to 70%, the number of strong Br{\o}nsted acid sites, that is those with a ΔHads between 120 and 140 kJ/mol, increases with increasing XRD crystallinity. A strong correlation was observed between the catalytic activity of these zeolite-based materials in terms of the demanding n-hexane cracking reaction and the number of strong acid sites. For samples with XRD crystallinities below 30%, however, the number of strong acid sites is disproportionately low and the catalytic activity only becomes significant at crystallinities above this level.",

keywords = "Aluminosilicate, Ammonia adsorption microcalorimetry, Br{\o}nsted acid, Cracking, NAS catalysts, Zeolite",

author = "Nicolaides, {C. P.} and Kung, {H. H.} and Makgoba, {N. P.} and Sincadu, {N. P.} and Scurrell, {M. S.}",

note = "Funding Information: Financial support from NSF (USA), and from NRF, SASOL, THRIP and the University of the Witwatersrand (all of South Africa), and experimental assistance from Dr. B.A. Williams, are gratefully acknowledged.",

year = "2002",

doi = "10.1016/S0926-860X(01)00706-2",

language = "English (US)",

volume = "223",

pages = "29--33",

journal = "Applied Catalysis A: General",

issn = "0926-860X",

publisher = "Elsevier",

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TY - JOUR

T1 - Characterization by ammonia adsorption microcalorimetry of substantially amorphous or partially crystalline ZSM-5 materials and correlation with catalytic activity

AU - Nicolaides, C. P.

AU - Kung, H. H.

AU - Makgoba, N. P.

AU - Sincadu, N. P.

AU - Scurrell, M. S.

N1 - Funding Information: Financial support from NSF (USA), and from NRF, SASOL, THRIP and the University of the Witwatersrand (all of South Africa), and experimental assistance from Dr. B.A. Williams, are gratefully acknowledged.

PY - 2002

Y1 - 2002

N2 - Ammonia adsorption microcalorimetry studies have shown that for ZSM-5-based materials, whose XRD crystallinity was varied from 3 to 70%, the number of strong Brønsted acid sites, that is those with a ΔHads between 120 and 140 kJ/mol, increases with increasing XRD crystallinity. A strong correlation was observed between the catalytic activity of these zeolite-based materials in terms of the demanding n-hexane cracking reaction and the number of strong acid sites. For samples with XRD crystallinities below 30%, however, the number of strong acid sites is disproportionately low and the catalytic activity only becomes significant at crystallinities above this level.

AB - Ammonia adsorption microcalorimetry studies have shown that for ZSM-5-based materials, whose XRD crystallinity was varied from 3 to 70%, the number of strong Brønsted acid sites, that is those with a ΔHads between 120 and 140 kJ/mol, increases with increasing XRD crystallinity. A strong correlation was observed between the catalytic activity of these zeolite-based materials in terms of the demanding n-hexane cracking reaction and the number of strong acid sites. For samples with XRD crystallinities below 30%, however, the number of strong acid sites is disproportionately low and the catalytic activity only becomes significant at crystallinities above this level.

KW - Aluminosilicate

KW - Ammonia adsorption microcalorimetry

KW - Brønsted acid

KW - Cracking

KW - NAS catalysts

KW - Zeolite

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U2 - 10.1016/S0926-860X(01)00706-2

DO - 10.1016/S0926-860X(01)00706-2

M3 - Article

AN - SCOPUS:0037050190

SN - 0926-860X

VL - 223

SP - 29

EP - 33

JO - Applied Catalysis A: General

JF - Applied Catalysis A: General

IS - 1-2

ER -

Characterization by ammonia adsorption microcalorimetry of substantially amorphous or partially crystalline ZSM-5 materials and correlation with catalytic activity

Abstract

Keywords

ASJC Scopus subject areas

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