Refining reaction kinetics of butadiene hydrogenation on zeolite-confined palladium clusters

• Published in: Molecular catalysis Vol. 546; p. 113278
• Main Authors: Wang, Yi, Yuan, Qiao, Shi, Lihua, Chen, Zhibing, Mou, Xiaoling, Li, Menglu, Dai, Jingwei, Song, Xiangen, Lin, Ronghe, Ding, Yunjie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2023
• Subjects: 1,3-Butadiene, Confinement effect; Hydrogenation, Palladium, Reaction kinetics; Hydrogenation, Palladium, Reaction kinetics; 1,3-Butadiene, Confinement effect
• ISSN: 2468-8231; 2468-8231
• DOI: 10.1016/j.mcat.2023.113278

•Pd clusters confined in ZSM-5 and supported on the outer surfaces were prepared.•Pd@ZSM-5 exhibited much improved butenes selectivity but lower hydrogenation activity.•The detailed reaction dynamics of hydrogenation and isomerization were studied.•The kinetic origin of high selectivity patterns on Pd@ZSM-5 was revealed. Palladium clusters confined within the micropores of ZSM-5 in protonic form (Pd@ZSM-5) are designed for the selective hydrogenation of 1,3-butadiene. Greatly enhanced selectivity to butenes at similar conversions is achieved on Pd@ZSM-5 as compared with the conventionally adsorption-derived nanoparticle counterpart (Pd/ZSM-5). Pd@ZSM-5 exhibits lower intrinsic activity that can be leveraged by increasing H2-to-butadiene ratio in the feed without sacrificing butenes selectivity. The size and electronic effects of the Pd species on their catalytic performance are discussed by coupling in situ diffuse reflectance infrared Fourier transform spectroscopy and the detailed reaction kinetics of the hydrogenation of butadiene and 1-butene, and the isomerization of 1-butene. It is revealed that the size and location of the Pd species may play a more decisive role in determining the hydrogenation performance rather than the nature of the surface Pd species. Palladium clusters confined in the zeolites channels do not change the π-bonding configuration of butadiene and the adsorption of H2, but significantly weaken the adsorption strength of both butadiene and the primary product - 1-butene, the key factors responsible for the selective hydrogenation. [Display omitted]