Doctoral Dissertations
Date of Award
12-2020
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Major
Chemical Engineering
Major Professor
Siris O. Laursen
Committee Members
Brian J. Edwards, Joshua R. Sangoro, Craig E. Barnes
Abstract
This study focuses upon understanding and rationally tuning the surface reactivity towards C, H, and O of non-noble metal intermetallic compounds (IMCs) catalysts in olefin production and hydrocarbons reforming reactions. In these reactions, different degrees of surface reactivity towards C, H, and O are required to achieve high activity and selectivity as well as stability. A combined computational and experimental method was performed to build this understanding how to rationally design catalysts. Investigations based on quantum chemical calculations indicate surface reactivity towards C, H, and O is a function of element size of constituent elements as well as bulk and surface composition, which also translates to reaction energetics of catalytic activity preference for each material. New BEP correlations are also evident over the IMCs that exhibit strong electronic effects and pronounced p-element contributions to the surface chemistry. Analysis of electronic structure beyond d-band center illustrates how the surface chemistry and nature of reaction site is dictated by density of d-states of TM and p-states of p-element near Fermi level, degree of their hybridization, and degree of covalent-like bonding within solids. Experimentally, a fundamental understanding of how to synthesize well-defined oxide-supported nanoparticle IMCs was established. It is found that the kinetics of IMC formation and control of surface composition is related to precursor choice, reduction temperature, H2 chemical potential, interaction between surface and support, and gas phase environment and temperature during annealing. Based on this understanding, oxide supported nanoparticle Ni+Ga IMCs with pure phase and controlled surface compositions were synthesized and investigated in propane steam reforming, which enabled the direct investigation of correlation between surface and catalytic chemistry and bulk and surface composition. This study provides directions on developing new materials that exhibit new, unique, and tunable surface chemistry, which will have considerable impact on the greater heterogeneous catalysis community.
Recommended Citation
Song, Yuanjun, "Rational Design of Non-noble Metal Intermetallic Compounds with Tunable Surface and Catalytic Chemistry via Combined Computational and Experimental Method. " PhD diss., University of Tennessee, 2020.
https://trace.tennessee.edu/utk_graddiss/6090