【摘 要】
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Pt-based catalysts are widely used in propane dehydrogenation reaction for the production of propylene.Suppressing irreversible deactivation caused by the sintering of Pt particles under harsh conditions and regeneration process is a significant challenge
【机 构】
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National Engineering Research Center of Chemical Fertilizer Catalyst,School of Chemical Engineering,
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Pt-based catalysts are widely used in propane dehydrogenation reaction for the production of propylene.Suppressing irreversible deactivation caused by the sintering of Pt particles under harsh conditions and regeneration process is a significant challenge in this catalyst.Herein,a series of highly ordered meso-porous Al2Os supports with different levels of Al3+penta sites,are fabricated and used as the support to dis-perse Pt-Sn2 clusters.Characterizations of Pt-Sn2/meso-Al2O3 with XRD,NMR,CO-IR,STEM,TG,and Raman techniques along with propane dehydrogenation-regeneration cycles test reveal the structure-stability-re generability relationship.The coordinatively unsaturated pentacoordinate Al3+ (Al3+penta) can strongly anchor Pt atoms via a formation of Al-O-Pt bond,and thus stabilize the Pt-based particles at the surface of Al2O3.The stability and regenerability of Pt-Sn2/meso-Al2O3 are strongly dependent on the content of Al3+penta sites in the Al2O3 structure,and a high level of Al3+Penta sites can effectively prevent the agglomeration of Pt-Sn2 clusters into large Pt nanoparticles in the consecutive dehydrogenation-regeneration cycles.The Pt-Sn2/meso-Al2O3-600 with the highest level of Al3+penta (50.8g) delivers the best performance in propane dehydro-genation,which exhibits propane conversion of 40% and propylene selectivity above 98% at 570 ℃ with 10 vol% CaH8 and 10 vol% H2 feed.A slow deactivation in this catalyst is ascribed to the formation of coke,and the catalytic performance can be fully restored in the consecutive dehydrogenation-regeneration cycles via a simple calcination treatment.
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