IR studies of the transformation of formaldehyde and methanol on Co-ferrierites

The transformation of the formaldehyde and methanol molecules with cobalt ions in zeolites CoFER containing various proportions between the Co2+ in the exchange positions and in the oxide forms was investigated by IR spectroscopy. Both formaldehyde and methanol molecules were oxidized to formate ions by Co3+ or Co2+ acting as oxidants. According to the IR results mainly Co3+ acts as the oxidant in the reaction with methanol, being reduced to Co2+. The status of Co3+ in zeolites was followed with NO as probe molecule whereas information on the nature of Co2+ was obtained in the IR experiments of low temperature CO sorption.

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► The interaction of formaldehyde with Co2+ results in the weakening of C=O bond.
► The electron flow from Co2+ to formaldehyde weakens the C=O bond.
► Formaldehyde and methanol are oxidized to the formate ions.
► The Co3+ ions in the oxide forms are oxidants. They are reduced to Co2+ in the exchange positions.