Activation of Mo and V oxides supported on ZSM-5 zeolite catalysts followed by in situ XAS and XRD and their uses in oxydehydration of glycerol

Possato, Luiz G. [UNESP]; Acevedo, Mauro D.; Padró, Cristina L.; Briois, Valérie; Passos, Aline R. [UNESP]; Pulcinelli, Sandra H. [UNESP]; Santilli, Celso V. [UNESP]; Martins, Leandro [UNESP]

Activation of Mo and V oxides supported on ZSM-5 zeolite catalysts followed by in situ XAS and XRD and their uses in oxydehydration of glycerol

Arquivos

2-s2.0-85051810041.pdf (2.65 MB)

Data

2018-01-01

Autores

Pulcinelli, Sandra H.

Santilli, Celso V.

Martins, Leandro

Tipo

Artigo

Direito de acesso

Acesso aberto

Resumo

This paper describes the activation and catalytic performance of a multifunctional catalyst consisting of mixed oxides of vanadium and molybdenum supported on an acidic ZSM-5 zeolite. The zeolite was wet-impregnated with an aqueous solution containing a mixture of NH4VO3 and (NH4)6Mo7O24 precursors at a V/(Mo+V) molar ratio of 0.6. Evolution of the phases during activation (by calcination under 20% O2/He) was followed by synchrotron X-ray diffraction (XRD), but detection of mixed oxides of MoxVyOz was difficult, due to the high degree of dispersion on the zeolite surface. On the other hand, X-ray absorption spectroscopy (XAS) performed simultaneously at the Mo and V K-edges enabled confirmation of formation of the MoV2O8 phase on the acidic ZSM-5 zeolite. The combination of the MoV2O8 phase and the zeolite acid sites produced a highly active catalyst for gas phase glycerol dehydration-oxidation coupled reactions in which acrylic acid was the main product. The multifunctional catalyst presented only 6% of deactivation during a period of 8 h under glycerol stream, while the activities of the bulk mixed oxide and the pure ZSM-5 zeolite decreased by almost 20 and 31%, respectively.