On the catalytic decomposition of formic acid. I. The activation energies for oxide catalysis

Literature data of the activation energies for the dehydration and the dehydrogenation reactions of formic acid over a series of oxide catalysts are treated to exemplify the idea of a stepwise variation of activation energies. By applying the formalism for the energy of an anharmonic vibrator, one can derive that very vibrational mode of the reacting intermediate (formate ion) that must be excited for the two reactions to occur. For the dehydration this is mainly the anharmonic O-C-O stretch and for the dehydrogenation reaction it is mainly the O-C-O in plane bending mode. An algorithm SETOS is presented that facilitates the analysis of the data. (C) 1998 Elsevier Science B.V.