Following the formation of active Co(III) sites in cobalt substituted aluminophosphates catalysts by in-situ combined UV-VIS/XAFS/XRD technique

Cobalt substituted aluminophosphates, CoAlPO‐34 (Chabazite structure) and DAF‐8 (Phillipsite structure) were investigated by in situ combined XRD/EXAFS/UV‐VIS technique. In‐situ combined XRD, Co K‐edge EXAFS and UV‐Vis measurements carried out during the calcination process reveal that CoAlPO‐34 containing 10 wt percent cobalt is stable and the cobalt ions are converted from Co(II) in the as synthesised form to Co(III); DAF‐8 containing about 25 percent cobalt is not stable and does not show change in oxidation state.