Structure of iron and manganese ions substituted in the framework of nanoporous AlPO-5 material

Authors: Sankar, Gopinahtan¹; Shiju, N. Raveendran¹; Watts, Ian D.¹; Nikitenko, Serge²; Bras, Wim²

Source: Research on Chemical Intermediates, Volume 34, Numbers 5-7, 2008 , pp. 649-658(10)

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Abstract:

The structure of iron and manganese ions substituted in the framework of nanoporous AlPO-5 is determined by ex situ and in situ X-ray absorption spectroscopy. Fe K-edge XANES and EXAFS studies clearly indicate that iron ions are present as Fe(III) in octahedral coordination in the assynthesised material and tetrahedral coordination in the calcined material in both pure FeAlPO-5 and FeMnalPO-5. XANES and EXAFS results also indicate that reaction with hydrogen peroxide causes the removal of Fe(III) ions from the framework. Mn K-edge XANES and EXAFS of FeMnAlPO-5 samples indicate that Mn(II) ions are present in the framework, tetrahedrally coordinated, in the as-synthesised material but upon calcination it is found that the Mn(II) ions are removed from the framework, suggesting a different synthesis strategy is necessary to stabilise the Mn(II) ions in the framework simultaneously with Fe(III) ions.

Keywords: AIPO-5; ION SUBSTITUTION; SPECTROSCOPY; COORDINATION

Document Type: Research article

DOI: http://dx.doi.org/10.1163/156856708784795644

Affiliations: 1: Davy Faraday Research Laboratory, The Royal Institution of GB, 21 Albemarle Street, London W1S 4BS, UK 2: DUBBLE@ESRF, BP 220 Grenoble 38143, France

Publication date: 2008-05-01