1. Synthesis and characterization of vanadosilicate AM-6 with transition metal ions isomorphously substituted in the framework
- Author
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Ismail, Mariam N., Ibe, Ugonna K., Chernenko, Tatyana, Diem, Max, Warzywoda, Juliusz, and Sacco, Albert
- Subjects
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POROUS materials , *SILICATES , *TRANSITION metal ions , *ENERGY-band theory of solids , *X-ray diffraction , *ABSORPTION , *SPECTRUM analysis - Abstract
Abstract: Isomorphous substitutions of transition metal (TM) ions into the vanadosilicate AM-6 framework have been investigated. X-ray powder diffraction and FTIR spectroscopy showed no impurities due to TM oxides (i.e., cobalt oxide, chromium oxide or iron oxide for Co-AM-6, Cr-AM-6 and Fe-AM-6, respectively) in all TM ion-substituted AM-6 products (TM-AM-6). All TM-AM-6 products showed a red shift of their bandgap energies (3.62–3.78eV) compared to unmodified AM-6 (3.82eV). New absorption features in the low energy region of the UV–Vis spectra of AM-6 were observed upon incorporation of the various TM ions, and the intensity of these new features increased with increasing crystal TM/V ratios. These low energy region absorption features suggested the presence of Fe3+, Cr3+, and Co2+ in Fe-AM-6, Cr-AM-6, and Co-AM-6, respectively. These findings together with shifts to higher frequency of the Raman bands observed for TM-AM-6 relative to unmodified AM-6 suggested successful partial isomorphous substitution in or near the VO6 chains in the AM-6 framework. [Copyright &y& Elsevier]
- Published
- 2011
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