Infrared studies of the surface of α-Fe2O3

The surface chemistry and structure of α-Fe2O3 obtained by thermal decomposition of α-FeOOH have been studied by IR spectroscopy. The spectra arising from the adsorption of some probe molecules (water, pyridine, ammonia, carbon monoxide, methanol) on samples after different pretreatments are analyzed, and the nature and behaviour of surface hydroxy groups, Lewis acid sites, acid-base couples and π-bonding adsorption sites are discussed. The results are interpreted on the basis of a disordered model of the {0001} crystal face that is predominantly exposed on such samples.