HYDROGEN ADSORPTION AND DESORPTION ON ALUMINA SUPPORTED PLATINUM-MULTICOMPONENT CATALYSTS WITH A GAS-CHROMATOGRAPHIC PULSE TECHNIQUE

A study of hydrogen chemisorption of multicomponent catalysts containing platinum as an active metal was performed by means of the pulse-flow chromatographic technique. Several series of adsorption experiments, performed at various constant intervals of time between hydrogen pulses, were carried out on each catalyst. During the experiments hydrogen desorption phenomena were observed. Hydrogen desorption was kinetically studied. The rate coefficients of the desorption reaction relevant to each catalyst were evaluated. Desorption has been discussed taking into account spillover effects. The occurrence of desorption phenomena gave rise to apparent adsorption parameters (i.e. platinum dispersion, platinum surface area), however proper parameters have been obtained by graphical extrapolation.