Towards an understanding of the oxidation state of cobalt and manganese ions in framework substituted microporous aluminophosphate redox catalysts: An electron paramagnetic resonance and X-ray absorption spectroscopy investigation

Phys Chem Chem Phys. 2005 Apr 21;7(8):1856-60. doi: 10.1039/b415570j.

Abstract

The local structure of manganese and cobalt ions in both the AlPO-5 and AlPO-18 materials was determined using electron paramagnetic resonance (EPR) and X-ray absorption spectroscopy (XAS). This study strongly suggested that both cobalt and manganese ions are present in the framework tetrahedral sites in the as-prepared materials. Upon calcination, in a dry atmosphere, both manganese and cobalt ions are partially oxidised to the 3+ state; the fraction of oxidised cobalt or manganese ions depends upon both the nature of the framework structure and on the ion type with manganese systems showing a higher proportion of oxidised cations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aluminum Compounds / chemistry
  • Catalysis
  • Cobalt / chemistry*
  • Electron Spin Resonance Spectroscopy*
  • Manganese / chemistry*
  • Molecular Conformation
  • Oxidation-Reduction
  • Phosphates / chemistry
  • Spectrometry, X-Ray Emission*

Substances

  • Aluminum Compounds
  • Phosphates
  • Cobalt
  • Manganese
  • aluminum phosphate