Pt-Cr/ZSM-5 catalysts for propane and cyclohexane conversions Original Research Article

The effect of chromium on the structural and catalytic properties was investigated for Pt-Cr/ZSM-5 system. From TPR measurements it is seen that the reduction profiles were modified by the addition of Cr to the Pt/ZSM-5. Chemissorption data showed that Cr promoted the Pt dispersion. The propane and cyclohexane reactions showed higher activity and aromatic selectivity for the bimetallic samples when compared to the single Pt/ZSM-5 system. Unlike the Pt/ZSM-5 catalyst at higher cyclohexane conversions the hydrogenolysis did not occur on the bimetallic system, and this behavior increases the efficiency by eliminating undesirable parallel reactions. The Pt–Cr interaction seems to be favored and not only prevents the migration of Pt particles to the external zeolite surface but also weakens the Pt interaction with reactant intermediates, inhibiting hydrogenolysis