Computation and Experimental Design of Intermetallic Compounds for the Production of Fuels from Greenhouse Gasses and Plastic Waste

Author

Max Keith Mortensen Jr., University of Tennessee, KnoxvilleFollow

Date of Award

5-2024

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemical Engineering

Major Professor

Siris O. Laursen

Committee Members

Stephen Paddison, Arthur Ragauskas, David Harper

Abstract

This dissertation is focused on understanding and rationally tuning the surface chemistry of Intermetallic Compounds (IMC) (compositionally order compounds of transition metals (TM) and p-block elements) towards carbon (C), hydrogen (H), and oxygen (O) for the reforming of methane and polyolefin cleavage reactions. Each reaction requires a different degree of surface chemistry towards C, H, and O to control the selectivity, stability, and activity of the catalyst. To better design the catalysts and create trends in surface chemistry that can be utilized for future reactions, a combination of computations and experiments were conducted. Density Functional Theory (DFT) calculations were utilized to understand the trends in surface chemistry, reaction pathways and key steps that control the selectivity, and changes in electronic structures that result in new surface chemistry presented by the early and late-TM IMCs. To gain further control over the kinetics, earlier-TMs were doped onto a binary IMC to further manipulate the reactivity of the catalyst to improve conversion, selectivity, and stability under reaction conditions. A major issue in the polyolefin reaction is the limited mass transport and uncatalyzed thermal radicals that limit the observation of catalytic surface chemistry. Therefore, a new pilot scale reactor was developed to improve mass transport and produce strain on the C–C bond backbone that resulted in lower temperature C–C bond cleavage to avoid uncatalyzed thermal radical. The combination of computations and experiments provided an improved understanding of rational catalyst design utilizing a suite of early and late-TM IMCs that produced a large range of catalytic surface chemistry.

Recommended Citation

Mortensen, Max Keith Jr., "Computation and Experimental Design of Intermetallic Compounds for the Production of Fuels from Greenhouse Gasses and Plastic Waste. " PhD diss., University of Tennessee, 2024.
https://trace.tennessee.edu/utk_graddiss/10147