Promoting effect of Ge on Pt-based catalysts for dehydrogenation of propane to propylene

In this study, a Ge-promoted Pt catalyst with enhanced performance for propane dehydrogenation (PDH) has been developed. Pt-0.5-Ge-1.5/Al2O3 shows outstanding stability and performance (deactivation parameter: 0.10 1/h, propylene selectivity: 97.2%) in comparison with the monometallic Pt-0.5/Al2O3 catalyst (deactivation parameter: 0.42 1/h, propylene selectivity: 56.9%). Effects of Ge loading (1.0%, 1.5%, 2.0%), reduction temperature and reaction temperature were investigated. Characterization techniques including XPS, BET, CO-DRIFTS, CO chemisorption, TG/DTA, RAMAN, XANES, and NH3-TPD were applied to study the fresh and spent catalysts. The modification of Pt structure and its electronic properties is ascribed to an alloy formation between Pt and Ge. Due to this alloy formation, Ge dilutes Pt surface, breaking the Pt ensembles and, at the same time, withdrawing electrons from Pt. As a result of these geometric and electronic modifications, superior performance of Pt-0.5-Ge-1.5/Al2O3 has been achieved.