Cristin-resultat-ID: 1354948
Sist endret: 5. mai 2017, 17:27
NVI-rapporteringsår: 2016
Resultat
Vitenskapelig artikkel
2016

Structural changes in SAPO-34 due to hydrothermal treatment. A NMR, XRD, and DRIFTS study

Bidragsytere:
  • Bjørnar Arstad
  • Anna Maria Lind
  • Jasmina Hafizovic Cavka
  • Knut Thorshaug
  • Duncan Akporiaye
  • David Wragg
  • mfl.

Tidsskrift

Microporous and Mesoporous Materials
ISSN 1387-1811
e-ISSN 1873-3093
NVI-nivå 2

Om resultatet

Vitenskapelig artikkel
Publiseringsår: 2016
Trykket: 2016
Volum: 225
Sider: 421 - 431
Open Access

Importkilder

Scopus-ID: 2-s2.0-84960334156

Beskrivelse Beskrivelse

Tittel

Structural changes in SAPO-34 due to hydrothermal treatment. A NMR, XRD, and DRIFTS study

Sammendrag

When SAPO-34 is used as an industrial MTO catalyst, structural transformations leading to permanent deactivation are inevitable. The performance loss is linked principally to a redistribution of Si in the material, leading to the formation of Si-islands/aggregates with a concomitant loss of Brønsted acidic sites and catalytic activity. In this work we have studied transformations taking place in a SAPO-34 sample after hydrothermal treatment by studying two samples with different levels of Si; 7 atomic % and 13 atomic % Si T-atoms, corresponding to about one and two Si per CHA cage respectively. The 13% Si sample contains significant amount of silicon islands in its as-synthesized form, while the 7% Si sample does not. The 7% Si sample was steamed for a week at 700 °C and a partial pressure of steam of 0.7 atm. The changes were analysed in the context of Si-island formation, and compared with the 13% Si sample. The results clearly illustrated existence of two distinct types of local aggregation of silicon: Silicon islands produced during synthesis and aggregate silicon reminiscent of silicon islands induced by hydrothermal treatment. The materials were synthesized with full 29Si isotopic enrichment and allowed us, for the first time, to characterise the multiplicity of silicon species in great detail by 29Si solid state NMR.

Bidragsytere

Bjørnar Arstad

  • Tilknyttet:
    Forfatter
    ved Prosessteknologi ved SINTEF AS

Anna Maria Lind

  • Tilknyttet:
    Forfatter
    ved Prosessteknologi ved SINTEF AS

Jasmina Hafizovic Cavka

  • Tilknyttet:
    Forfatter
    ved Prosessteknologi ved SINTEF AS

Knut Thorshaug

  • Tilknyttet:
    Forfatter
    ved Materialer og nanoteknologi ved SINTEF AS

Duncan Akporiaye

  • Tilknyttet:
    Forfatter
    ved Prosessteknologi ved SINTEF AS
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