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layout: single title: “Research Thrusts” permalink: /research/ date: 2018-4-25 categories: pages —

1. Computational Catalysis

(i) CO2 Conversion to high-value chemicals

Persistent growth in global energy demands, depletion of fossil fuel resources and rising concentrations of atmospheric carbon dioxide (CO2) – a known greenhouse gas, are of great environmental concern. Innovative methods for CO2 capture, storage, and utilization are of marked interest for mitigating elevated levels of CO2 in the atmosphere. The utilization (chemical conversion) of CO2 for the production of high-value chemicals has gained tremendous research interest recently. Despite considerable work on catalyst interactions with CO2, kinetic limitations are still present in industrial processes that can utilize CO2 as a chemical feedstock. I apply Density Functional Theory, Ab-initio Molecular Dynamics and Atomistic Thermodynamics to understand and design catalysts for CO2 reduction to high-value chemicals.

Representative Publication:

Dixit, M., Peng, X., Porosoff, M. D., Willauer, H. D., and Mpourmpakis, G., Elucidating the role of oxygen coverage in CO2 reduction on Mo2C. Catal. Sci. Tech. 7, 5521-5529 (2017) Featured on the front cover

(ii) C-H Activation and Dehydrogenation of Alkanes on Metal Oxides

Olefins are important chemical building blocks for the production of a wide range of valuable chemicals and plastics. A promising route to produce olefins is the non-oxidative dehydrogenation of alkanes on metal oxides. We provide fundamental insights into the various mechanisms of alkane dehydrogenation on Metal oxides and identify structure-activity relationships, by using Density Functional Theory and Ab-inito Molecular Dynamics calculations.

2. Electrochemical Energy Storage

Rechargeable Li and Na ion Batteries

The excellent performance of lithium ion batteries (LIB) has led to a revolution in portable electronic devices, and nowadays LIBs are empowering electric vehicles (EVs). Among the various factors influencing the performance of LIBs, the positive electrode (cathode) material is arguably the most important component, as the nature of the cathode primarily controls the capacity and the stability of LIBs. Using a combined experimental and first-principles theory approach we investigate lithiated metal oxide-based electrode materials.

Representative Publications:

(1) Jun, D. W.; Kim, U. H.; Park, K. J.; Aurbach, D.; Major, D. T.; Goobes, G.; Dixit, M.; Leifer, N.; Wang, C.; Yan, P.; Ahn, D.; Kim, K. H.; Yoon, C. S.; Sun, Y. Y. Pushing the limit of layered transition metal oxide cathodes for high-energy density rechargeable Li-ion batteries. Energy Environ. Sci. (2018).

(2) Dixit, M.; Kosa, M.; Srur Lavi, O.; Markovsky, B.; Aurbach, D.; Major, D. T. Thermodynamic and Kinetic Studies of LiNi0.5Co0.2Mn0.3O2 as a Positive Electrode Material for Li-ion Batteries using First Principles. Phys. Chem. Chem. Phys. 2016, 18, 6799-6812.

(3) Dixit, M.; Markovsky, B.; Schipper, F.; Aurbach, D.; Major, D. T. The Origin of Structural Degradation During Cycling and Low Thermal Stability of Ni-rich Layered Transition Metal-Based Electrode Materials. J. Phys. Chem. C. 2017, 121, 22628-22636.

(4) Schipper, F.; Dixit, M.; Kovacheva, D.; Talianker, M.; Haik, O.; Grinblat, Y.; Erikson, E. M.; Ghanty, C.; Major, D. T.; Markovsky, B.; Aurbach, D. Stabilizing Nickel-Rich Layered Cathode Materials by a High-Charge Cation Doping Strategy: Zirconium-Doped LiNi0.6Co0.2Mn0.2O2. J. Mater. Chem. A 2016, 4, 16073-16084.

(5) Dixit, M.; Engel, H.; Eitan, R.; Aurbach, D.; Levi, M.; Kosa, M.; Major, D. T. Classical and Quantum Modeling of Li and Na Diffusion in FePO4. J. Phys. Chem. C 2015, 119, 15801-15809.

(6) de la Llave, E.; Talaie, E.; Levi, E.; Kumar, P.; Dixit, M.; Rao, P. T.; Hartmann, P.; Chesneau, F. F.; Major, D. T.; Greenstein, M.; Aurbach, D.; Nazar, L. F. Improving Energy Density and Structural Stability of Manganese Oxide Cathodes for Na-ion Batteries by Structural Lithium Substitution. Chem. Mater. 2016, 28, 9064-9076.

3. Enzyme Simulations: Chemical Control in Terpene Synthases:

Terpene cyclases catalyze the highly stereospecific molding of polyisoprenes into terpenes, which are precursors to most known natural compounds. The isoprenoids are formed via intricate chemical cascades employing rich, yet highly erratic, carbocation chemistry. It is currently not well understood how these biocatalysts achieve chemical control. We illustrated the catalytic control exerted by terpene synthases, and in particular, we discover main features that could be general catalytic tools adopted by terpenoid cyclases.

Representative Publications:

  1. Dixit. M; Weitman, M; Gao, J; Major, D.T. Chemical Control in the Battle against Fidelity in Promiscuous Natural Product Biosynthesis: The Case of Trichodiene Synthase. ACS Catal., 2017,7 (1), 812–818

  2. Dixit, M.; Weitman, M.; Gao, J.; Major, D. T. Comment on “Substrate Folding Modes in Trichodiene Synthase: A Determinant of Chemo- and Stereoselectivity”. ACS Catalysis 2018, 8, 1371-1375