Abstract:
Of the various forms of hydrogen adsorbed on platinum only hydrogen weakly and reversibly
adsorbed is detected by an infra-red band at 2120 cm-1. The preparation of a well dispersed sample
of Pt/ALO? catalyst containing 10 % platinum allows us to determine accurately the hydrogen
adsorption isotherm of this weakly adsorbed species. Only a dissociative Langmuir model fits the
experimental results in the pressure range of 10'1 to 700 Torr and temperature range of 27 to 95°C.
The heat of adsorption (—5 x 104 J mol-1) and the isosteric heat of adsorption are in good agree
ment with previous calorimetric data.
