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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Vanadosilicate with MWW zeolite structure synthesized from VCl3 by cooperative assembly of organic templates

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Author(s):
Chaves, Thiago F. [1, 2] ; Passos, Aline R. [3] ; Briois, Valerie [3] ; Martins, Leandro [1] ; Pulcinelli, Sandra H. [1] ; Santilli, Celso V. [1] ; Perez-Pariente, Joaquin [2]
Total Authors: 7
Affiliation:
[1] UNESP Univ Estadual Paulista, Inst Quim, Rua Prof Francisco Degni 55, BR-14800060 Araraquara, SP - Brazil
[2] CSIC, ICP, C Marie Curie 2, Madrid 28049 - Spain
[3] Synchrotron SOLEIL, Orme Merlsiers, BP 48, F-91192 Gif Sur Yvette - France
Total Affiliations: 3
Document type: Journal article
Source: Microporous and Mesoporous Materials; v. 279, p. 252-261, MAY 1 2019.
Web of Science Citations: 0
Abstract

Aluminum-free MWW structure containing vanadium was easily prepared from a mixture of suitable templates (N,N,N-trimethyl-1-adamantamonium hydroxide (TMAdaOH) and hexamethyleneimine (HMI)). Besides, the use of VCl3 as vanadium source, in which this metal is in low oxidation state (V3+) and the preparation of the synthesis gel under inert atmosphere are crucial to get an efficient incorporation of vanadium into the zeolitic framework. UV-Vis spectrum of the as-synthesized material whose oxidation was prevented by working under inert atmosphere reveals the presence of isolated V3+ sites isomorphically coordinated. Besides, the Si-29 MAS NMR spectra and the V K-edge X-ray Absorption Spectroscopy (XAS) analysis show that the vanadium was incorporated into the zeolite framework with formation of V-O-Si linkages. C-13 MAS NMR evidences that both templates are present in the as-synthesized material, showing that the mixture of TMAdaOH and HMI is crucial for obtaining pure crystalline vanadosilicate phase. XAS measurements of the V-containing zeolite during calcination under air showed that initially the sample contains V4+ sites in a square pyramidal geometry, which were completely oxidized to isolated V5+ in T-d coordination after calcination. (AU)

FAPESP's process: 14/11952-5 - Study of the formation of ordered hierarchical materials by a supramolecular structure in emulsions using zeolite precursors
Grantee:Thiago Faheina Chaves
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 15/25850-2 - Synthesis and catalytic application of hierarchical materials obtained from lamellar precursors containing vanadium
Grantee:Thiago Faheina Chaves
Support type: Scholarships abroad - Research Internship - Post-doctor