Gallium substituted L, mordenite and ferrierite zeolites, obtained through wet impregnation, were characterized combining adsorption isotherms, X-ray powder diffraction (XRPD) and X-ray absorption spectroscopy (XAS) to elucidate nature and structure of the Ga+3 sites of the materials. The saturation capacity of L was higher than those of mordenite and ferrierite. Rietveld refinements on saturated materials confirm the presence of Ga+3 within the zeolites pores system. Besides, the analysis of the structural features (i.e., lightening of tetrahedral bond distances and narrowing of interthetraedral angles) suggest that small fractions of metal cation have been also incorporated in tetrahedral sites. This is corroborated by XAS analysis, which confirms the effective inclusion of gallium into the zeolites frameworks, thus indicating that the incorporation of Ga+3 from wet impregnation within the zeolite structures occurs in both framework and non-framework positions.
Insights on Ga-zeolite catalysts: X-ray powder diffraction and absorption spectroscopy characterization at ambient conditions / Beltrami, G.; Chenet, T.; Pasti, L.; Gigli, L.; Pollastri, S.; Martucci, A.. - In: CATALYSIS TODAY. - ISSN 0920-5861. - 345:(2020), pp. 147-156. [10.1016/j.cattod.2019.09.016]
Insights on Ga-zeolite catalysts: X-ray powder diffraction and absorption spectroscopy characterization at ambient conditions
Pollastri S.;
2020
Abstract
Gallium substituted L, mordenite and ferrierite zeolites, obtained through wet impregnation, were characterized combining adsorption isotherms, X-ray powder diffraction (XRPD) and X-ray absorption spectroscopy (XAS) to elucidate nature and structure of the Ga+3 sites of the materials. The saturation capacity of L was higher than those of mordenite and ferrierite. Rietveld refinements on saturated materials confirm the presence of Ga+3 within the zeolites pores system. Besides, the analysis of the structural features (i.e., lightening of tetrahedral bond distances and narrowing of interthetraedral angles) suggest that small fractions of metal cation have been also incorporated in tetrahedral sites. This is corroborated by XAS analysis, which confirms the effective inclusion of gallium into the zeolites frameworks, thus indicating that the incorporation of Ga+3 from wet impregnation within the zeolite structures occurs in both framework and non-framework positions.
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