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

Autor(es)

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]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Microporous and Mesoporous Materials; v. 279, p. 252-261, MAY 1 2019.
• Citações Web of Science: 0

Resumo

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)

• Processo FAPESP: 14/11952-5 - Estudo da formação de materiais hierárquicos ordenados por uma estrutura supramolecular em emulsões utilizando precursores zeolíticos
• Beneficiário: Thiago Faheina Chaves
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 15/25850-2 - Síntese e aplicação catalítica de materiais hierárquicos obtidos a partir de precursores lamelares contendo vanádio
• Beneficiário: Thiago Faheina Chaves
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado