Degree Type

Thesis

Date of Award

2020

Degree Name

Doctor of Philosophy

Department

Chemical and Biological Engineering

Major

Chemical Engineering

First Advisor

Brent H Shanks

Abstract

To address to the requirement of catalysts for biomass conversion, palladium-basedcatalysts were studied for aqueous phase hydrogenation, especially carbonyl group, which is common in the biomass-derived molecules. A three-phase fixed-bed reactor was used to evaluate the catalysts’ performance. XRD, XPS, TEM, ICP, chemisorption, TCD and IR were used to characterize the catalyst surface. A Pd-Fe bimetallic catalyst was found to be more active than its Pd monometallic counterpart. Then the Pd-Fe catalysts were used to study the kinetic of acetone hydrogenation in aqueous phase to explain the fundamental reason for the activity enhancement compared with Pd. Based on the knowledge of Pd-Fe and Pd system, more Pd-based bimetallic catalysts will be synthesized and tested for the same reaction, in attempt to correlate the electron property and the catalytic performance. The secondary metals include Cu, Zn, Cr, and W. The addition of Fe in Pd catalysts forms PdFe nanoalloys, which was attributed to the improved activity of acetone. The PdFe bimetallic catalysts were considerably more active than Pd catalysts not only for carbonyl hydrogenation, but also for aromatic rings and C=C bonds, although to a lower extent to which the activity was enhanced. The primary results from the kinetic study suggested that PdFe increased activity by altering the favorable acetone adsorption configuration from di-σ (η2) to on top (η1) and reducing the activation energy of surface reaction. Besides Fe, Cu and Zn were found to be promoters to different degrees, while Cr and W impeded the reaction significantly.

DOI

https://doi.org/10.31274/etd-20210114-26

Copyright Owner

Yan Cheng

Language

en

File Format

application/pdf

File Size

144 pages

Available for download on Saturday, January 07, 2023

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