James Shogren-Harris, Assistant Professor, Hewson Engineering Faculty Fellow, the University of Alabama, Chemical and Biological Engineering

"Identifying Roles of Distinct Surface Sites for Oxygenate Conversion Over Metal Catalysts"

Abstract:

Understanding the structure of primary binding sites in heterogeneous catalysts, as well as the role of their local environment is paramount to developing complete molecular scale descriptions of chemistry occurring over these sites. In this seminar, I will give two examples of oxidation catalysis of metal catalysts of varied complexity. In the first, I will report on our efforts to prepare supported bimetallic catalysts for oxidative coupling reactions (e.g., of methanol and dimethylamine to form dimethylformamide) across a range of dilute bimetallic (M₁-M₂) nanoparticles of varied M₁ and M₂ identities and M₁:M₂ ratios (0<M₁:M₂<∞). Analysis of X‑ray absorption fine structure (XAFS) spectra suggest small PdAu nanoparticles are alloyed, and that Pd segregates such that Au:Pd ratios determined from Pd coordination numbers are lower than bulk Au:Pd ratios. These studies demonstrate the benefits of isolating small ensembles of oxyphilic metals within coinage metal hosts. The impact of nanoparticle size and promoters on the rates, selectivity and reaction kinetics over bimetallic PdAu particles of varied sizes will be discussed. In the second example, I will discuss our contributions related to the production of sustainable aviation fuel (SAF) from renewable alcohols. This reaction occurs over multifunctional copper-, zinc-, and yttrium-containing dealuminated Beta zeolites, via a series pathway requiring dehydrogenation, aldol condensation, hydrogenation, and dehydrations in a precise sequence. We have quantified the number of Lewis acidic active sites in these materials via ex situ and in situ chemical titrations, and find that there is evidence for at least two types of yttrium sites that collectively catalyze dehydration, aldol condensation, and Meerwein-Pondorff-Verley reduction. The kinetics of butadiene formation from ethanol-acetaldehyde mixtures over monometallic yttrium- or lanthanum-containing dealuminated Beta zeolite catalysts are disparate, suggesting predictable differences in these metals as primary binding sites for adsorption and conversion of small oxygenates. These findings aid in our ongoing efforts to reduce the cost and carbon footprint of SAF production.

Bio:

James W. Harris received a B.S. in Chemical Engineering from the University of Virginia in 2012 and a Ph.D. in Chemical Engineering from Purdue University in 2017. Harris joined the Department of Chemical and Biological Engineering at The University of Alabama as an Assistant Professor in Fall 2019. His research group is involved in projects related to the responsible use of energy carriers for production of fuels and chemicals. Professor Harris is particularly interested in catalysis occurring over metal surfaces whose properties evolve as a function of their environment, and over sites confined within the pores of zeolites. Professor Harris has been awarded the Oak Ridge Affiliated Universities Ralph E. Powe Award, the University of Alabama Undergraduate Research and Creative Activity Conference’s “Top Faculty Mentor” award, the American Chemical Society’s Petroleum Research Fund (PRF) Doctoral New Investigator Award, was named a “Young Talent” by the 18^th International Congress on Catalysis, and was named a “Pioneer of Catalysis and Reaction Engineering” by the AIChE CRE Division. He was awarded the NSF CAREER award in 2024. In 2025, he received the University of Alabama’s President’s Faculty Research award, The University of Alabama’s Early Career Research Excellence & Innovation Award and Faculty Excellence in Professional Service Award, and The University of Alabama Department of Chemical Engineering’s William H. Melson Award for Research Excellence. His group’s research is supported by the ACS Petroleum Research Fund, the Aviation Climate Taskforce, the National Science Foundation, the U.S. Department of Defense, and the U.S. Department of Energy. Harris serves as the programming co-chair for the AIChE CRE Division, as an alternate councilor for the ACS CATL division, as the past-president of the Southeastern Catalysis Society (SECS), and as a member of the Early Career Council Board of the journal Microporous and Mesoporous Materials. In his spare time, Dr. Harris enjoys cycling and playing tennis.