Correlation between properties of supported RhCu catalysts and procedure of preparation

Two series of catalysts were characterized. Only the impregnation method was different in the procedure of preparation of the catalysts of series 1 and of series 2. Hydrogen chemisorption isotherms are measured on pure Rh and on RhCu alloys supported on silica in extended ranges of temperature (193-500K) and pressure (10-2 -103 Pa). The derived isosteric heat of adsorption Qiso as a function of the coverage is different on the alloy of one of the two series only as compared to Qiso on pure rhodium. The surface area available to hydrogen chemisorption exhibits the inverse behaviour. The values of dispersion and particles size measured by TEM and by hydrogen chemisorption are in agreement. A model of the metal particles based on the differences in impregnation procedures is proposed to account for the difference of properties of alloys of series 1 and series 2. © 1989.SCOPUS: ar.j