Pt-Cu Alloy Nanoparticles Encapsulated in Silicalite-1 Molecular Sieve: Coke-Resistant Catalyst for Alkane Dehydrogenation

摘要

Highly dispersed Pt-Cu alloy nanoparticles encapsulated in silicalite-1 were prepared by one-pot method. Taking propane dehydrogenation as a probe reaction, it was found that anti-coke ability was improved by encapsulation. Through H-2-TPR, CO adsorption DRIFT spectra and X-ray Photoelectron Spectroscopy experiment, enhanced anti-coke ability was ascribed to the electronic environment change of encapsulated metal. And it was further confirmed by in situ coking experiment. Owning to limited acidity, metal encapsulated by silicalite-1 molecular sieve exhibited better anti-coke ability and higher propylene selectivity than that by stronger acidic ZSM-5 molecular sieve. Moreover it was found that the combination of Cu and Pt made better catalytic performance and accelerated dehydrogenation more effectively compared with monometallic catalysts. Therefore, Pt-Cu alloy nanoparticles encapsulated in silicalite-1 molecular sieve core-shell material was a potential coke-resistant catalyst for alkane dehydrogenation reaction.