The IR spectroscopy of methane and hydrogen adsorbed on alpha-chromia

The vibrational perturbations induced in the IR spectra of methane and of d ihydrogen by the non-dissociative adsorption on the (01 (1) over bar 2) and (11 (2) over bar 0) faces of alpha-chromia are illustrated and compared. I t is concluded that both molecules are adsorbed on Cr3+ sites and that the involved forces are mainly of the electrostatic type. The resulting situati on is compared with that found on the more basic MgO. The problems associat ed with the C-H and H-H bond activations on transition metal oxides are als o discussed.