V-P-O catalysts supported on the surface of silica and titania particles were studied and compared with bulk V-P-O. The catalytic performance was tested in the n-butane oxidation reaction to maleic anhydride, and the structure of the equilibrated catalysts was characterised with X-ray absorption spectroscopy (EXAFS) and (low-temperature) ESR spectroscopy. Our results show considerable differences in catalytic performance between VPO/TiO(2) on the one hand, and VPO/SiO(2) and VPO/bulk on the other hand, the yield to maleic anhydride being comparable for VPO/bulk and VPO/SiO(2). The differences in catalytic behaviour are attributed to differences in the local structure around vanadium (EXAFS). Furthermore, different spin exchange interactions between vanadium atoms in the three samples have been observed (ESR). The combination of characterisation methods suggests that the structure of the supported V-P-O phase is amorphous and differs considerably from that of bulk crystalline vanadylpyrophosphate. We therefore propose that the oxidation of n-butane to maleic anhydride takes place over an amorphous surface V-P-O phase. This finding has high relevance for our understanding of the catalytic activity of bulk crystalline V-P-O catalysts as well.

The Selective Oxidation of Butane to Maleic Anhydride : Development of Silica- and Titania-Supported V-P-O Catalysts

BARBON, ANTONIO;
1998

Abstract

V-P-O catalysts supported on the surface of silica and titania particles were studied and compared with bulk V-P-O. The catalytic performance was tested in the n-butane oxidation reaction to maleic anhydride, and the structure of the equilibrated catalysts was characterised with X-ray absorption spectroscopy (EXAFS) and (low-temperature) ESR spectroscopy. Our results show considerable differences in catalytic performance between VPO/TiO(2) on the one hand, and VPO/SiO(2) and VPO/bulk on the other hand, the yield to maleic anhydride being comparable for VPO/bulk and VPO/SiO(2). The differences in catalytic behaviour are attributed to differences in the local structure around vanadium (EXAFS). Furthermore, different spin exchange interactions between vanadium atoms in the three samples have been observed (ESR). The combination of characterisation methods suggests that the structure of the supported V-P-O phase is amorphous and differs considerably from that of bulk crystalline vanadylpyrophosphate. We therefore propose that the oxidation of n-butane to maleic anhydride takes place over an amorphous surface V-P-O phase. This finding has high relevance for our understanding of the catalytic activity of bulk crystalline V-P-O catalysts as well.
1998
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/148023
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 34
  • ???jsp.display-item.citation.isi??? 30
social impact