(532bn) Tuning the Reactivity for Propane Dehydrogenation By Using Well-Defined, Single-Phase Pt-Sn Nano-Catalysts

Propane dehydrogenation along with its competing side reactions (dry reforming, hydrogenolysis, propane cracking and others) are structure-sensitive reactions. The co-exitance of such side reactions, that evidently leading to C−C cracking and coke deposition, that leads to quick deactivation and the need for continuous regeneration, therefor, the design of suitable catalysts to selectively activate the alkane C-H bond challenging. Platinum-tin catalysts have been much studied for the dehydrogenation of propane to propene (PDH) but due to the complexity of the chemistry and structure of nanoparticles that are formed via wet impregnation it has been difficult to definitively understand the effect of the different phases. Here we report the successful synthesis of 2-3 nm PtSn and Pt₃Sn nanocrystals using a seed mediating approach. These nanocrystals are supported on gamma-alumina and tested as catalysts for PDH. The selective formation of specific active phases insures the stability of the catalyst with a deactivation rate ten times less than the classical impregnated Pt and PtSn catalytic systems respectively. Furthermore, the reactivity of the formed PtSn nanocatalyst tunes the reactivity for propylene formation depending on the hydrogen rich or poor environment in the feed. These catalysts are characterized using TEM, HAADF-STEM, FTIR and operando XAS. These new systems reveal the structure dependency of the propane dehydrogenation reaction and provide a fundamental understanding of the structure−performance relationship on PtSn catalyst systems and emerging bimetallic system. We extended the study to other Pt-based catalysts with promising results and higher activity.