Chemistry and spectroscopy of vanadium in VAPO-5 molecular sieves

Bert M. Weckhuysen; Ina P. Vannijvel; Robert A. Schoonheydt

doi:10.1016/0144-2449(95)00027-4

Chemistry and spectroscopy of vanadium in VAPO-5 molecular sieves

Bert M. Weckhuysen^*
, Ina P. Vannijvel
, Robert A. Schoonheydt

^*Corresponding author for this work

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

Abstract

VAPO-5 molecular sieves were synthesized hydrothermally starting with different vanadium, phosphorus, and template contents and with different templates as a function of time. The crystallization process was followed by X-ray diffraction and scanning electron microscopy; the coordination of vanadium was investigated by diffuse reflectance spectroscopy (d.r.s.) and electron spin resonance (e.s.r.). In the gels, vanadium is present as an octahedral ion and can be washed off easily. The crystallization process is retarded by increasing the vanadium content and gel (V + Al)/P ratios different from 1. Good crystalline materials were obtained by using tripropylamine, triethylamine, and tetrapropylammoniumhydroxide as template and synthesis times between 48 and 120 h. In the as-synthesized samples, isolated (pseudo-)octahedral V⁴⁺ is detected by e.s.r. and d.r.s. This vanadium is accessible by ammonia and comprises only 10% of the total vanadium content. Upon calcination, V⁴⁺ ions are oxidized to tetrahedral V⁵⁺, which can only be reduced partially to V⁴⁺. On this basis, no unambiguous evidence is found for isomorphous substituted vanadium in AlPO-5 molecular sieves.

Original language	English
Pages (from-to)	482-489
Number of pages	8
Journal	Zeolites
Volume	15
Issue number	6
DOIs	https://doi.org/10.1016/0144-2449(95)00027-4
Publication status	Published - Aug 1995
Externally published	Yes

Bibliographical note

Funding Information:
B.M.W. acknowledgeths eB elgianN ationalF und for ScientificR esearch( NFWO) for a grant as research assistanat nd for a travelg rantto visit the University of Mancheste(rU K). The use of the e.s.r, simulation softwareo f David Collisona ndFrank Mabbs( University of Manchestera) nd their advice are gratefully acknowledgedT.h is work was supportedfi nancially by the Fonds voor KollectiefF undamenteeOln der-zoek (KFKO) Grant 2.0050.93a nd by the Geconcer-teerdeO nderzoeksactie(GsO A/94/3)of the Flemish government.

Funding

B.M.W. acknowledgeths eB elgianN ationalF und for ScientificR esearch( NFWO) for a grant as research assistanat nd for a travelg rantto visit the University of Mancheste(rU K). The use of the e.s.r, simulation softwareo f David Collisona ndFrank Mabbs( University of Manchestera) nd their advice are gratefully acknowledgedT.h is work was supportedfi nancially by the Fonds voor KollectiefF undamenteeOln der-zoek (KFKO) Grant 2.0050.93a nd by the Geconcer-teerdeO nderzoeksactie(GsO A/94/3)of the Flemish government.

Keywords

d.s.r.
e.s.r
isomorphous substitution
microporous aluminophosphates
synthesis
VAPO-5

Access to Document

10.1016/0144-2449(95)00027-4

Cite this

@article{4e19ca267c064c06a750d82f12aba543,

title = "Chemistry and spectroscopy of vanadium in VAPO-5 molecular sieves",

abstract = "VAPO-5 molecular sieves were synthesized hydrothermally starting with different vanadium, phosphorus, and template contents and with different templates as a function of time. The crystallization process was followed by X-ray diffraction and scanning electron microscopy; the coordination of vanadium was investigated by diffuse reflectance spectroscopy (d.r.s.) and electron spin resonance (e.s.r.). In the gels, vanadium is present as an octahedral ion and can be washed off easily. The crystallization process is retarded by increasing the vanadium content and gel (V + Al)/P ratios different from 1. Good crystalline materials were obtained by using tripropylamine, triethylamine, and tetrapropylammoniumhydroxide as template and synthesis times between 48 and 120 h. In the as-synthesized samples, isolated (pseudo-)octahedral V4+ is detected by e.s.r. and d.r.s. This vanadium is accessible by ammonia and comprises only 10\% of the total vanadium content. Upon calcination, V4+ ions are oxidized to tetrahedral V5+, which can only be reduced partially to V4+. On this basis, no unambiguous evidence is found for isomorphous substituted vanadium in AlPO-5 molecular sieves.",

keywords = "d.s.r., e.s.r, isomorphous substitution, microporous aluminophosphates, synthesis, VAPO-5",

author = "Weckhuysen, \{Bert M.\} and Vannijvel, \{Ina P.\} and Schoonheydt, \{Robert A.\}",

note = "Funding Information: B.M.W. acknowledgeths eB elgianN ationalF und for ScientificR esearch( NFWO) for a grant as research assistanat nd for a travelg rantto visit the University of Mancheste(rU K). The use of the e.s.r, simulation softwareo f David Collisona ndFrank Mabbs( University of Manchestera) nd their advice are gratefully acknowledgedT.h is work was supportedfi nancially by the Fonds voor KollectiefF undamenteeOln der-zoek (KFKO) Grant 2.0050.93a nd by the Geconcer-teerdeO nderzoeksactie(GsO A/94/3)of the Flemish government.",

year = "1995",

month = aug,

doi = "10.1016/0144-2449(95)00027-4",

language = "English",

volume = "15",

pages = "482--489",

journal = "Zeolites",

issn = "0144-2449",

publisher = "Elsevier BV",

number = "6",

}

TY - JOUR

T1 - Chemistry and spectroscopy of vanadium in VAPO-5 molecular sieves

AU - Weckhuysen, Bert M.

AU - Vannijvel, Ina P.

AU - Schoonheydt, Robert A.

N1 - Funding Information: B.M.W. acknowledgeths eB elgianN ationalF und for ScientificR esearch( NFWO) for a grant as research assistanat nd for a travelg rantto visit the University of Mancheste(rU K). The use of the e.s.r, simulation softwareo f David Collisona ndFrank Mabbs( University of Manchestera) nd their advice are gratefully acknowledgedT.h is work was supportedfi nancially by the Fonds voor KollectiefF undamenteeOln der-zoek (KFKO) Grant 2.0050.93a nd by the Geconcer-teerdeO nderzoeksactie(GsO A/94/3)of the Flemish government.

PY - 1995/8

Y1 - 1995/8

N2 - VAPO-5 molecular sieves were synthesized hydrothermally starting with different vanadium, phosphorus, and template contents and with different templates as a function of time. The crystallization process was followed by X-ray diffraction and scanning electron microscopy; the coordination of vanadium was investigated by diffuse reflectance spectroscopy (d.r.s.) and electron spin resonance (e.s.r.). In the gels, vanadium is present as an octahedral ion and can be washed off easily. The crystallization process is retarded by increasing the vanadium content and gel (V + Al)/P ratios different from 1. Good crystalline materials were obtained by using tripropylamine, triethylamine, and tetrapropylammoniumhydroxide as template and synthesis times between 48 and 120 h. In the as-synthesized samples, isolated (pseudo-)octahedral V4+ is detected by e.s.r. and d.r.s. This vanadium is accessible by ammonia and comprises only 10% of the total vanadium content. Upon calcination, V4+ ions are oxidized to tetrahedral V5+, which can only be reduced partially to V4+. On this basis, no unambiguous evidence is found for isomorphous substituted vanadium in AlPO-5 molecular sieves.

AB - VAPO-5 molecular sieves were synthesized hydrothermally starting with different vanadium, phosphorus, and template contents and with different templates as a function of time. The crystallization process was followed by X-ray diffraction and scanning electron microscopy; the coordination of vanadium was investigated by diffuse reflectance spectroscopy (d.r.s.) and electron spin resonance (e.s.r.). In the gels, vanadium is present as an octahedral ion and can be washed off easily. The crystallization process is retarded by increasing the vanadium content and gel (V + Al)/P ratios different from 1. Good crystalline materials were obtained by using tripropylamine, triethylamine, and tetrapropylammoniumhydroxide as template and synthesis times between 48 and 120 h. In the as-synthesized samples, isolated (pseudo-)octahedral V4+ is detected by e.s.r. and d.r.s. This vanadium is accessible by ammonia and comprises only 10% of the total vanadium content. Upon calcination, V4+ ions are oxidized to tetrahedral V5+, which can only be reduced partially to V4+. On this basis, no unambiguous evidence is found for isomorphous substituted vanadium in AlPO-5 molecular sieves.

KW - d.s.r.

KW - e.s.r

KW - isomorphous substitution

KW - microporous aluminophosphates

KW - synthesis

KW - VAPO-5

UR - https://www.scopus.com/pages/publications/0029358943

U2 - 10.1016/0144-2449(95)00027-4

DO - 10.1016/0144-2449(95)00027-4

M3 - Article

AN - SCOPUS:0029358943

SN - 0144-2449

VL - 15

SP - 482

EP - 489

JO - Zeolites

JF - Zeolites

IS - 6

ER -

Chemistry and spectroscopy of vanadium in VAPO-5 molecular sieves

Abstract

Bibliographical note

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Cite this