Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions

Author(s)

Vieira, Luiz H. ^{[1, 2]} ; Possato, Luiz G. ^[2] ; Chaves, Thiago F. ^[2] ; Lee, Jason J. ^[1] ; Sulmonetti, Taylor P. ^[1] ; Jones, Christopher W. ^[1] ; Martins, Leandro ^[2]

Affiliation

^[1] Georgia Inst Technol, Sch Chem & Biomol Engn, 311 Ferst Dr NW, Atlanta, GA 30332 - USA

^[2] Univ Estadual Paulista UNESP, Inst Quim, R Prof Francisco Degni 55, BR-14800900 Quitandinha, SP - Brazil

• Document type: Journal article
• Source: CHEMCATCHEM; v. 12, n. 1, p. 141-151, JAN 8 2020.
• Web of Science Citations: 0

Abstract

Supported transition metal catalysts have been extensively applied to oxidative and reductive processes. The understanding of surface speciation and active site-support interactions in these materials play a substantial role in developing improved heterogeneous catalysts. Herein, a series of impregnated 3D Ferrierite and 2D ITQ-6 siliceous supports with variable loading of vanadium oxide were prepared. Chemical and structural properties of the materials were studied by X-ray diffraction, N-2 physisorption, inductively coupled plasma - optical emission spectrometry, X-ray absorption, Fourier transform infrared and diffuse reflectance UV-vis spectroscopies, and temperature-programmed reduction with H-2. Reactivity of surface, associated with the incidence of isolated silanol groups, was found to be more effective to better disperse and stabilize vanadium oxides than increase in surface area. Differences in activation and the oxidation state dynamics behavior of active sites were then probed by methanol oxidation as a model reaction monitored by in situ FTIR and XANES/MS. Keeping isothermal steps of reaction (in absence of oxidant) and regeneration by O-2 it was found that, even at distinct rates, all species of vanadium oxides on surface are able to oxide methanol but reoxidation of reduced sites is limited and, probably, a determinant step to V5+/V4+ equilibrium when reaction is carried in the presence of oxidant. (AU)

• FAPESP's process: 18/01258-5 - Novel chemical catalytic and photocatalytic processes for the direct conversion of methane and CO2 to products
• Grantee: José Maria Correa Bueno
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/00860-0 - A study on selective oxidation of methanol over lamellar vanadosilicates catalysts
• Grantee: Luiz Henrique Vieira
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 14/20116-6 - Development and application of lamellar vanadosilicates as catalysts in the glycerol oxidative dehydration
• Grantee: Luiz Henrique Vieira
• Support Opportunities: Scholarships in Brazil - Doctorate