Study of H-(beta)-zeolite supported Rh catalyst by inverse gas chromatography

Catalysts containing rhodium (Rh) were prepared by the wet impregnation method using H-_-zeolite as support. Retention time of three n-alkanes (C5–C7), cyclohexane, benzene, trichloroethylene and tetrachloroethylene on the Rh/H-_-zeolite catalysts (0.5–2.0 wt%of Rh) and H-(beta)-zeolite were measured by inverse gas chromatography (IGC) in the 473.2–513.2K temperature range. Standard free energy of adsorption, dispersive component of surface free energy of adsorbent and specific interaction parameters between polar probes and catalysts were evaluated. The results indicate that the adsorption characteristics of H-(beta)-zeolite can be modified by rhodium. Surface area, enthalpy of adsorption and dispersive component of surface free energy decrease after the impregnation of rhodium. Besides, it was found that rhodium dispersed in the framework of H-(beta)-zeolite had special adsorption for benzene which may be useful for making catalysts for certain reactions involving benzene in the future.