Analysis of coordination environment of aluminum species in zeolites and amorphous silica-alumina by X-ray absorption and emission spectroscopy

• X-ray emission spectra recorded with a commercially available wavelength dispersive XRF spectrometer.
• Three kinds of spectra for each zeolite samples were identical to those of four-coordinated reference compounds.
• Energy shift obtained by XANES spectroscopy has good correlation with those evaluated by WD-XRF and EXEFS.
• WD-XRF and EXEFS techniques are useful for coordination environmental analysis for Al species as well as 27Al NMR and XANES.

The coordination numbers of Al species in zeolites and amorphous silica alumina samples were investigated with three kinds of X-ray spectroscopic technique: namely, X-ray absorption near edge structure (XANES), wavelength dispersive X-ray fluorescence (WD-XRF), and extended X-ray emission fine structure (EXEFS) spectroscopies. XANES, WD-XRF and EXEFS spectra of zeolite samples were identical to those of four-coordinated reference compounds and were distinguishable from those for six-coordinated samples. The energy shift obtained by XANES spectroscopy showed good correlation with those evaluated by WD-XRF and EXEFS.

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