Ethane Oxidative Dehydrogenation over Pt-Rare Earth Intermetallic Compounds with CO₂ as Soft Oxidant

Intermetallic Pt-M (M = La, Y, and Sc) nanoparticlessupportedon zeolite nanosponge (ZNS) were synthesized and investigated forethane oxidative dehydrogenation (EOD) with CO2 as a softoxidant. Among all the catalysts examined, ZNS-supported Pt5La1 nanoparticles had the best dispersion with an averageparticle size of 1.25 nm and the highest CO uptake of 34.7 & mu;molg(-1), surpassing the catalytic performance by 37%ethane conversion and 28% ethylene yield. The XPS results confirmedthat some La species co-exist with Pt5La1 inthe form of LaO x . LaO x facilitated the facile engagement of CO2, leadingto enhanced catalyst stability and improved CO2 conversion.Furthermore, the LaO x -catalyzed reverseBoudouard reaction (CO2 + C & RARR; 2CO) aided in thepartial removal of deposited carbonaceous coke during the catalyticreaction. Apart from that, the gradual decrease after each regenerationcycle was inevitable due to the surface metal sintering.