DETERMINATION OF THE ACTIVATION-ENERGY OF A SURFACE-REACTION WITH A COMPLEX THERMAL-DESORPTION SPECTRUM

A method of experimental temperature programming and processing of the results obtained for surface processes is described; it allows finding the activation energies in the presence of a complex spectrum in one experiment where the initial degree of surface filling or concentration of the reactant is not known and without preliminary assumptions concerning the kinetic model, order of the process, and value of the preexponential factor. The method was used for studying thermal decomposition of surface rhenium hydride complexes, the intermediate unit in two-stage low-temperature thermochemical decomposition of water by the Re3Cl9 complex adsorbed on silica. Four overlapping phases with E(ef) = 75, 150, 240, and 240 kJ/mole were distinguished in the thermal desorption spectrum of hydrogen up to 850 K.