Effects of Pt loading on the activity of Pt/γ-Ga2O3 for propane dehydrogenation

Abstract

The efficient and selective activation of C–H bonds in propane is a crucial challenge in catalysis, particularly for the on-purpose production of propene through propane dehydrogenation (PDH). This study investigates the intrinsic catalytic effect of platinum supported on γ-Ga₂O₃ (Pt/γ-Ga₂O₃) for the PDH reaction. Comprehensive characterization of these catalysts was conducted using techniques such as XRD, N₂ adsorption–desorption, SEM, HRTEM, XPS, NH₃-TPD, H₂/CO-TPR, and TPSR. The primary focus of this investigation was to examine the C–H bond activation and structure–reactivity relationships that were observed in Pt/γ-Ga₂O₃ catalysts during the PDH process. It is observed that the rate of propene formation over Pt/γ-Ga₂O₃ increases with Pt loading, however, exhibiting two distinct regions with different extents of increment. Experimental results demonstrated that the introduction of Pt into γ-Ga₂O₃ significantly enhances the C–H bond activation ability, as evidenced by a substantial reduction in the propane activation temperature. Furthermore, in situ PDH–MS results suggest that surface hydroxyl groups are likely involved in the initial C–H bond activation, promoting a transient oxidative dehydrogenation pathway before the reaction proceeds predominantly via non-oxidative dehydrogenation. Although the Pt/γ-Ga₂O₃ catalysts deactivate rapidly due to coke deposition, their initial activity is largely restored by air regeneration, but gradually decreases. The introduction of metal nanoparticles into bulk metal oxides, as demonstrated in this study, offers an alternative approach for controlling the C–H bond activation pathway, leading to improved propene production.