(7es) Mechanisms of Heterogeneous Catalysis for Clean Energy Conversion and Efficient Chemical Production

Postdoctoral Research Scholar

Postdoctoral Research: Chemical Looping Redox Catalyst

Syngas Production: Chemical looping-reforming replaces the gaseous oxygen of oxidative reforming with the lattice oxygen of a redox-catalyst. This technology can improve the efficiency of Gas-to-liquid (GTL) processes. I formulated and characterized novel high-selectivity, high-oxygen capacity core-shell redox catalysts for this system. I reported that there were 4 distinct reaction regions for this type of catalyst, which have subsequently been observed in several related systems. My research also shows that the selectivity of a redox catalyst with high internal oxygen mobility is determined by the types of oxygen species available at the redox catalyst surface.

Chemical Looping-Oxidative Dehydrogenation of Ethane: I co-invented a licensed chemical-looping redox catalyst for oxidative dehydrogenation of ethane (ODH). My research demonstrates that this approach can give high yields and selectivity without the significant dilution typically needed in co-feed ODH. In follow-up work I developed kinetics for the design of a pilot unit currently under construction.

Thesis Research:

Ph.D. Dissertation: “Nano-Particle Supported Catalyst”Advised by Dr. Helena Hagelin-Weaver in the Department of Chemical Engineering at the University of Florida

The oxidative coupling of 4-methyl-pyridines to 4,4′-Dimethyl-2,2′-bipyridine is a green chemistry process and a useful probe reaction. Palladium on metal oxide supports had previously been reported as inactive for this reaction. By synthesizing and extensively characterized multiple palladium catalysts, I showed that “inert” nano-particle metal-oxide supports can induce similar behavior in platinum-group-metal catalysts typically associated with oxides exhibiting strong metal-support interactions resulting in high activity.

Research and Funding Successes: I have authored or co-authored 18 refereed articles on a variety of catalytic reactions. I have supervised multiple research projects, mentoring over 12 graduate and undergraduate researchers, and have participated in the writing of 6 funding proposals and multiple SOPOs, and reports leading to project successes. I co-invented a novel chemical looping ODH technology which secured a $3.8 million overall plus-up from DOE/ARPA-E. My work has led to 3 provisional and 2 nonprovisional patent applications 2 of which were licensed to a commercial partner.

Future Direction: Catalysis is the classic means of “process intensification” in reaction engineering, but new insights into catalyst performance by mechanistic studies of real, practical catalysts is needed to keep pace with growing demands for clean energy and chemical production worldwide. My research on both supported platinum-group metal- and mixed-metal-oxide redox- catalysts will contribute to improved mechanistic understanding of greener, low-emission catalytic processes. My future research will focus upon bridging the gap between real-world catalyst performance and fundamental studies on model systems. The goal of this emphasis is to build mechanistic tools to guide rational development of more efficient industrial catalysts. I will also actively pursue multi-dispensary collaboration. For example, system modeling is valuable for evaluating the interaction between process economics and catalyst performance parameters. Model catalyst development and characterization in collaboration with computer simulation for determining catalyst mechanisms is also important. I also welcome other opportunities to expand my knowledge by using my expertise in heterogeneous catalysis in support of my colleagues’ research programs.

Research Interests: Building on my experience in practical reaction experimentation and mechanistic characterization of commercially relevant catalysts, I plan to conduct research in three areas: I) Oxygen storage materials for NO_x emissions reduction catalyst; II) Mechanisms of oxygenate formation in hydrocarbon systems; III) Unburned hydrocarbon oxidation over true earth-abundant materials.

Rational design of oxygen storage materials for enhanced NO_x reduction and advance combustion: Several emissions catalyst rely on “oxygen storage material” (OSM) supports. These materials allow the catalyst to oxidize hydrocarbons and CO in the presence of low pressures of oxygen and/or reducing agents needed for the suppression/reduction of NO_x. Rational design of OSMs has, so far, focused heavily on oxygen capacity at operating temperatures. Research on direct NO_x reduction catalysts has shown that other properties are impotent, but has tended to limit studies to unrealistically low N₂ and O₂ concentrations. My work will look at a full range of parameters, including oxygen-vacancy formation energies, internal oxygen transport rates and surface site pH. The principles developed will allow the rational design of improved emissions abatement catalysts.

Mechanistic study of oxygenate formation: The creation of alcohols and other oxygenates from alkanes is simultaneously a desired energy conversion process and a nuisance. Unwanted oxygenates can entrain water, poison catalysts, and add complexity to separations. However, oxygenate formation in processes such as gas-to-liquids and steam cracking is not well understood. I plan to use n-butane dehydrogenation as a model system. My research will probe a variety of catalysts with differing selectivities for oxygenate to determine underlying mechanisms. My studies will include in-situ/operando measurements, as well as surface characterizations. This project will yield mechanistic insights that guide suppression of oxygenates, while potentially developing improved catalysts for on-purpose oxygenate production and other processes.

True earth-abundant materials for deep oxidation of UHCs and CO: Novel, inexpensive mixed-metal-oxides will be used for deep oxidation of unburned hydrocarbons (UHCs) and carbon monoxide emitted in flue gases. Some redox catalysts, including Mg₆MnO₈ and SrMnO₃, have significant deep oxidation activity. These mixed oxides can exhibit better thermal stability and poisoning resistance than traditional platinum-group metal (PGM) catalysts, while potentially working well in very low partial pressures of oxygen. They can also be made more cheaply than typically proposed rare-earth oxides. Understanding the flexible properties of these true earth-abundant metal oxides can guide improvement of coal and biomass energy conversion efficiency, while lowering catalyst costs.

Teaching Interests: I welcome the opportunity to teach courses; I am capable of teaching any core undergraduate chemical-engineering course, and I have found that revisiting core chemical engineering concepts opens up deeper understanding of the subject. My background in applied, heterogeneous catalysis has given me particular skills and experiences well suited to teaching undergraduate courses relating to mass balances, thermodynamics, kinetics, and design. I am also interested in teaching graduate-level courses in kinetics and surface sciences, as well as special topic courses in catalysis and energy conversion. I am committed to studying and implementing teaching theory and techniques such as active learning. My approach to teaching has been molded by my experience as a TA and guest lecturer, as well as my supervision and mentoring of graduate and undergraduates in laboratory research. I have TA’d undergraduate students in thermodynamics and unit operations, and I have trained, mentored, and supervised over a dozen graduate and undergraduate students in their research, including setting research plans for three master students and a Ph.D. student. These mentoring interactions have included numerous international and four women and minority students. I am committed to pursuing further diversity through teaching and providing research opportunities.

Selected Publications:

S. Yusuf⁺, Luke M. Neal⁺, F. Li. “Effect of Promoters on Manganese Containing Mixed Metal Oxides for Oxidative Dehydrogenation of Ethane via a Cyclic Redox Scheme.” ACS Catalysis, Accepted (2017); (+Co-first authors);

Luke M. Neal⁺, S. Yusuf⁺, F. Li. “Oxidative Dehydrogenation of Ethane: A Chemical Looping Approach.” Energy Technology, 4: 1200 (2016); (+Co-first authors);

Luke M. Neal, A. Shafiefarhood, F Li. “Effect of Core and Shell Compositions on MeOx@La_ySr_1−yFeO₃ Core–Shell Redox Catalysts for Chemical Looping Reforming of Methane.” Applied Energy 157, 391–398 (2015);

Luke M. Neal, A. Shafiefarhood, F. Li. “Dynamic Methane Partial Oxidation Using an Fe₂O₃@La_0.8Sr_{0. 2}FeO_3-δ Core–Shell Redox Catalyst in the Absence of Gaseous Oxygen.” ACS Catalysis, 4: 3560–3569 (2014);

Luke M. Neal, M. Everett, G. Hoflund, H. Hagelin-Weaver. “Characterization of Palladium Oxide Catalysts Supported on Nanoparticle Metal Oxides for the Oxidative Coupling of 4-Methlypyridine.” Journal of Molecular Catalysis A: Chemical, 335: 210-22 (2011);

Luke M. Neal, S. D. Jones, M. L. Everett, G. B. Hoflund, H. E. Hagelin-Weaver. “Characterization of Alumina-Supported Palladium Oxide Catalysts in the Oxidative Coupling of 4-Methylpyridine.” Journal of Molecular Catalysis A: Chemical, 325: 25-35 (2010).

Nonprovisional Patent Applications:

F. Li, Luke M. Neal. “Ethylene Yield in Oxidative Dehydrogenation of Ethane and Ethane Containing Mixtures.” US 15/422,743 (2017);

J.A. Sofranko, F. Li, F. Li, Luke M. Neal. “Oxygen Transfer Agents for the Oxidative Dehydrogenation of Hydrocarbons and Systems and Processes Using the Same.” US 62/054,424 (2015).