(6bk) Dynamic Heterogeneous Catalysis to Enhance Turnover Frequency Via Surface Resonance

(i) Dynamic surface resonance for heterogeneous catalysis via microkinetic modeling and experiments. The greatest rate limitation in catalysis, the Sabatier maximum, is overcome by imposing a dynamic variation of catalyst surface electronic characteristics, leading to surface coverages and surface reaction rates that exceed the existing classes of known metal catalysts. Catalytic Resonance Theory (CRT) also permits unique capability for tuning individual reactions and selectively controlling reactions for small-scale, high-throughput reactors for energy, water and fuel applications.

(ii) Experiments on automated Lewis acid and redox site counting and characterization (i.e. redox potential, Lewis acid strength). Lewis acidic and redox active catalysts play key roles in industrial chemistries such as selective catalytic reduction of NOx, alkene oxidation, and aldol condensation. Fundamental comparisons between different catalyst formulations are difficult because there are few to no methods that can quantitatively assess Lewis acidity or redox activity. In-situ treatment with acidic oxygenate molecules under FTIR, UV-vis, or gravimetric observation can selectively titrate Lewis acid centers, allowing for site counting and strength assessment.

(iii) Molecular modeling and experiments on synthesis of chemoselective solid Lewis base and Lewis acid catalysts using layer by layer methods such as atomic layer deposition (ALD), chemical vapor deposition (CVD), and chemical liquid deposition (CLD). Lewis basic catalysts are highly efficient hydrolysis, isomerization, and Knoevenagel condensation catalysts. Their properties, structures, and behavior are largely unknown as solid acid catalysts are frequently more popular in the academic community. Using a combination of periodic DFT (VASP) and experiment: Lewis basic single sites, oligomers, and clusters are studied.

Postdoctoral Project:

"Principles of Dynamic Heterogeneous Catalysis: Enhanced Turnover Frequency and Conversion via Surface Resonance"

Under the supervision of Paul J. Dauenhauer, Department of Chemical Engineering and Materials Science, University of Minnesota

PhD Dissertation:

"Depositing SiO₂ on Metal Oxides to Synthesize Tunable Solid Acid Catalysts"

Under the supervision of Justin M. Notestein, Department of Chemical and Biological Engineering, Northwestern University

Undergraduate Research:

"Reaction Engineering to Optimize Furfural Yields from Real and Ideal Xylose Feedstock"

Under the supervision of James A. Dumesic and David Martin Alonso, Department of Chemical and Biological Engineering, University of Wisconsin - Madison

Research Experience:

My academic career has concentrated on the field of heterogeneous catalysis with complementary DFT, microkinetic modeling, and experimental projects. Most of my formal training is in controlled synthesis of metal and metal oxide catalysts, reaction engineering of liquid phase biomass reactions, and using vapor phase reactions/spectroscopy techniques to characterize solid acid catalysts. I have collaborated often with computational groups including a project with the Broadbelt group at Northwestern, focusing on the homogeneous and heterogeneous epoxidation of limonene with environmentally friendly H₂O₂ or industry standard organic peroxides. As a result of my collaborations and experiences, I have versatile experience in materials science, reactor design, sol-gel processing, infrared spectroscopy, NMR, adsorption/chemisorption, and DFT.

Teaching Interests:

My teaching experience consists of four teaching assistant quarters with three being for the senior Process Design course and one being for the senior Chemical Engineering Practice Laboratory. I won the Chemical and Biological Engineering department TA award in 2015 for my work as a Process Design TA because in Fall 2014; I redesigned/delivered 12 lectures on pumps, distillation, and reactors as the primary professor was on leave for that quarter. I am interested in teaching/designing the curriculum for Process Design, the Chemical Engineering Practice Laboratory, and perhaps a specially designed course on Heterogeneous Catalysis and/or Reaction Engineering.

Future Directions:

As a faculty member I want to explore and expand on dynamic heterogeneous catalysis and ‘Catalytic Resonance Theory’ as it has the potential to transform the entire field of heterogeneous catalysis. In particular, I want to leverage chemistry and synthetic knowledge from my PhD to investigate the use of chemical modifiers to change binding energies on the catalyst surface. Careful control of the solvent environment, partial pressure, and catalyst structure is needed to achieve optimal performance. These projects will necessitate the combined application of many techniques with DFT catalyst/adsorption screening, microkinetic modeling, and experiments working together to explain complex adsorption/reaction phenomena.

In parallel, I want to develop new classes of catalytic materials leveraging my PhD experience with catalysts synthesis using layer-by-layer techniques. Innovation is needed for supported metal catalysts, solid bases, and bifunctional materials where catalytically inactive sites assist with adsorption. Automated and precise characterization techniques will be developed in tandem to compare new formulations to standard catalysts. My overall philosophy will be to use DFT catalyst screening in combination with precise catalysts synthesis/materials science to select catalytic systems with high adsorption affinity for the reactants of interest (i.e. small molecules, methane, methanol, ethanol) and high reactivity/productivity.

Selected Publications:

M. A. Ardagh, O. A. Abdelrahman, and P. J. Dauenhauer, 2019. "Principles of Dynamic Heterogeneous Catalysis: Surface Resonance and Turnover Frequency Response". ACS Catalysis. doi: https://doi.org/10.1021/acscatal.9b01606 [online ahead of print]

M. A. Ardagh, Z. Bo, S. L. Nauert, and J. M. Notestein, 2016. "Depositing SiO₂ on Al₂O₃: a Route to Tunable Brønsted Acid Catalysts". ACS Catalysis, 6 (9), 6156-6164.

Z. Bo, S. Ahn, M. A. Ardagh, N. M. Schweitzer, C. P. Canlas, O. K. Farha, and J. M. Notestein, 2018. "Synthesis and Stabilization of Small Pt Nanoparticles on TiO₂ Partially Masked by SiO₂". Applied Catalysis A: General, 551, 122-128.