Structure-Activity Relations in Heterogeneous Catalysis – A View from Computational Chemistry

Phillipe Sautet
Friday, March 17, 2017 - 9:30am to 10:30am

The understanding of the catalytic properties of nanoparticle catalysts and the design of optimal composition and structures demands fast methods for the calculation of adsorption energies. By exploring the adsorption of O and OR (R=OH, OOH, OCH3) adsorbates on a large range of surface sites with 9 transition metals, we propose new structure sensitive scaling relations between the adsorption energy of two adsorbates that are valid for all metals and for all surface sites.1 This opens the way for a new class of activity volcano plots where the descriptor is not an energy...

In Silico Searches for Efficient Renewable Energy Catalysts Through Chemical Compound Space

John Keith
Friday, February 3, 2017 - 11:30am to 12:30pm

This talk will provide an overview of our group’s work using both standard and atypical high-performance computational chemistry modeling to elucidate atomic scale reaction mechanisms of catalytic reactions. I will introduce our toolkit of in silico methods for accurately modeling solvating environments and realistic nanoscale architectures. I will then present how these methods can be used for predictive insights into chemical and material design. The talk will then summarize our progress in unraveling reaction mechanisms for 1) electrochemical CO2 reduction with...

Personal | Department
Department of Chemical and Petroleum Engineering, University of Pittsburgh
Ph.D., Theoretical and Computational Chemistry, University of Crete, 2006

My research expertise is interdisciplinary, blending concepts and techniques from Chemistry, Physics, Materials Science and Chemical Engineering. I use theory and computation to investigate the physicochemical properties of nanomaterials with potential applications in diverse nanotechnological areas, ranging from energy generation and storage, to materials design, nanoparticle growth, magnetism, and catalysis.

In the Computer-Aided Nano and Energy Lab (C.A.N.E.LA.), led by Prof. Mpourmpakis, we use theory and computation to investigate the physicochemical properties of nanomaterials with potential applications in diverse nanotechnological areas, ranging from green energy generation and storage to materials engineering and catalysis. Our laboratory core expertise lies on "ab-initio" electronic-structure theoretical calculations. We develop structure-activity relationships and apply multiscale tools to elucidate complex chemical processes that take place on nanomaterials. Ultimately, we design novel nanostructures with increased, molecular-level precision and tailored multifunctionality. 

Most Cited Publications: 
  1. "SiC Nanotubes:  A Novel Material for Hydrogen Storage," Giannis Mpourmpakis and George E. Froudakis, George P. Lithoxoos and Jannis Samios, Nano Lett. 6, 1581 (2006)
  2. "Carbon Nanoscrolls:  A Promising Material for Hydrogen Storage," Giannis Mpourmpakis, Emmanuel Tylianakis, and George E. Froudakis, Nano Lett. 7, 1893 (2007)
  3. "Correlating Particle Size and Shape of Supported Ru/γ-Al2O3 Catalysts with NH3 Decomposition Activity," Ayman M. Karim, Vinay Prasad, Giannis Mpourmpakis, William W. Lonergan, Anatoly I. Frenkel, Jingguang G. Chen and Dionisios G. Vlachos, J. Am. Chem. Soc.131, 12230 (2009)
  4. "Stabilization of Si-based cage clusters and nanotubes by encapsulation of transition metal atoms," Antonis N Andriotis, Giannis Mpourmpakis, George E Froudakis2 and Madhu Menon, New J. Phys. 4, 78 (2002)
  5. "Why boron nitride nanotubes are preferable to carbon nanotubes for hydrogen storage?: An ab initio theoretical study," Giannis Mpourmpakis, George E. Froudakis, Catalysis Today 120, 341 (2007)
Recent Publications: 
  1. "CO2 activation on bimetallic CuNi nanoparticles," Natalie Austin, Brandon Butina, Giannis MpourmpakisProgress in Natural Science: Materials International 26, 487 (2016)
  2. "From Biomass-Derived Furans to Aromatics with Ethanol over Zeolite," Ivo F. Teixeira, Benedict T. W. Lo, Pavlo Kostetskyy, Michail Stamatakis, Lin Ye, Chiu C. Tang, Giannis Mpourmpakis, Shik Chi Edman Tsang, Angew. Chem. Int. Ed. 55, 13061 (2016)
  3. "Molecular modifiers reveal a mechanism of pathological crystal growth inhibition," Jihae Chung, Ignacio Granja, Michael G. Taylor, Giannis Mpourmpakis, John R. Asplin & Jeffrey D. Rimer, Nature 536, 446 (2016)
  4. "Description and Role of Bimetallic Prenucleation Species in the Formation of Small Nanoparticle Alloys," Lauren E. Marbella, Daniel M. Chevrier, Peter D. Tancini, Olabobola Shobayo, Ashley M. Smith, Kathryn A. Johnston, Christopher M. Andolina, Peng Zhang, Giannis Mpourmpakis, and Jill E. Millstone, J. Am. Chem. Soc. 137, 15852 (2015)
  5. "Catalyst Design Based on Morphology- and Environment-Dependent Adsorption on Metal Nanoparticles," Michael G. Taylor, Natalie Austin, Chrysanthos E. Gounaris, and Giannis MpourmpakisACS Catal. 5, 6296 (2015)

Oxide-metal Interfaces as Active Sites for Acid-base Catalysis: Oxidation State of Nanocatalyst Change with Decreasing Size, Conversion of Heterogeneous to Homogeneous Catalysis, Hybrid Systems

Gábor A. Somorjai
Friday, May 6, 2016 - 9:30am to 10:30am

When metal nanoparticles are placed on different mezoporous or microporous oxide supports the catalytic turnover rates and selectivities markedly change.  The charge flow between the metal and the oxide ionizes the adsorbed molecules at the oxide-metal interfaces and alters the catalytic chemistry (acid-base catalysis). 

The oxidation state of metal nanoparticles becomes less metallic and assume higher oxidation states with decreasing size.  The...

Metal Nanocatalysts, Their Synthesis and Size Dependent Covalent Bond Catalysis: Instrumentation for Characterization under Reaction Conditions

Gábor A. Somorjai
Thursday, May 5, 2016 - 5:00pm to 7:00pm

Colloidal chemistry is used to control the size, shape and composition of metal nanoparticles usually in the 1-10 nm range.  In-situ methods are used to characterize the size, structure (electronic and atomic), bonding, composition and oxidation states under reaction conditions.  These methods include sum frequency generation nonlinear optical spectroscopy (SFG), ambient pressure X-ray photoelectron spectroscopy (APXPS) and high pressure scanning tunneling...

Personal | Department
Department of Chemistry, University of Pittsburgh
Ph.D., Computational Organic Chemistry, University of California, 2010

Reactivity and Selectivity Rules in Organic and Organometallic Reactions
We are developing computational models to quantitatively describe the origins of reactivity and selectivity in organocatalytic and transition metal-catalyzed reactions. We perform quantum mechanical calculations to explore the reaction mechanism, followed by thorough analysis on various stereoelectronic effects to predict how changes of the catalyst structure, substituents, and solvent affect rate and selectivity. We use quantitative energy decomposition methods to dissect the key interactions in the transition state and provide chemically meaningful interpretation to the computed reactivity and selectivity. We apply these computational studies to a broad range of organic and organometallic reactions, such as C–H and C–C bond activations, coupling reactions, olefin metathesis, and polymerization reactions. 

Catalyst Screening and Prediction
We are developing a multi-scale computational screening protocol which could efficiently rank the catalysts based on ligand-substrate interaction energies in the transition state. 

Applications of Computational Chemistry in Understanding Organic Chemistry
We are collaborating with experimental groups at Pitt and many other institutions to solve problems in organic chemistry using computational methods and programs. Our goal is to establish the most effective strategy to use modern computational methods and hardware to help address the grand challenges in synthetic chemistry. 


Most Cited Publications: 
  1. "Computational Studies of Ruthenium-Catalyzed Olefin Metathesis," Peng Liu, Buck LH Taylor, Jesus Garcia-Lopez, Kendall N Houk, Handbook of Metathesis, 2nd Edition, Volume 1: Catalyst Development and Mechanism (2015)
  2. "Computational Explorations of Mechanisms and Ligand-Directed Selectivities of Copper-Catalyzed Ullmann-Type Reactions," Gavin O. Jones, Peng Liu, K. N. Houk and Stephen L. Buchwald, J. Am. Chem. Soc. 132, 6205 (2010)
  3. "Suzuki−Miyaura Cross-Coupling of Aryl Carbamates and Sulfamates: Experimental and Computational Studies," Kyle W. Quasdorf, Aurora Antoft-Finch, Peng Liu, Amanda L. Silberstein, Anna Komaromi, Tom Blackburn, Stephen D. Ramgren, K. N. Houk, Victor Snieckus, and Neil K. Garg, J. Am. Chem. Soc. 133, 6352 (2011)
  4. "Z-Selectivity in Olefin Metathesis with Chelated Ru Catalysts: Computational Studies of Mechanism and Selectivity," Peng Liu, Xiufang Xu, Xiaofei Dong, Benjamin K. Keitz, Myles B. Herbert, Robert H. Grubbs, and K. N. Houk, J. Am. Chem. Soc. 134, 1464 (2012)
  5. "Palladium-Catalyzed Meta-Selective C–H Bond Activation with a Nitrile-Containing Template: Computational Study on Mechanism and Origins of Selectivity," Yun-Fang Yang, Gui-Juan Cheng, Peng Liu, Dasheng Leow, Tian-Yu Sun, Ping Chen, Xinhao Zhang, Jin-Quan Yu, Yun-Dong Wu, and K. N. Houk, J. Am. Chem. Soc. 136, 344 (2014)
Recent Publications: 
  1. "1,3-Dipolar Cycloaddition Reactions of Low-Valent Rhodium and Iridium Complexes with Arylnitrile N-Oxides," Ilke Ugur, Sesil Agopcan Cinar, Burcu Dedeoglu, Viktorya Aviyente, M. Frederick Hawthorne, Peng Liu, Fang Liu, K. N. Houk, and Gonzalo Jiménez-Osés, J. Org. Chem., Article ASAP
  2. "Synthesis of Boriranes by Double Hydroboration Reactions of N-Heterocyclic Carbene Boranes and Dimethyl Acetylenedicarboxylate," Timothy R. McFadden, Cheng Fang, Steven J. Geib, Everett Merling, Peng Liu, and Dennis P. Curran, J. Am. Chem. Soc. 139, 1726 (2017)
  3. "Benzazetidine synthesis via palladium-catalysed intramolecular C−H amination," Gang He, Gang Lu, Zhengwei Guo, Peng Liu & Gong Chen, Nature Chemistry 8, 1131 (2016)
  4. "Catalytic activation of carbon–carbon bonds in cyclopentanones," Ying Xia, Gang Lu, Peng Liu & Guangbin Dong, Nature 539, 546 (2016)
  5. "Photoredox-mediated Minisci C–H alkylation of N-heteroarenes using boronic acids and hypervalent iodine," Guo-Xing Li, Christian A. Morales-Rivera, Yaxin Wang, Fang Gao, Gang He, Peng Liu and Gong Chen, Chem. Sci. 7, 6407 (2016)
Personal | Department
Department of Chemical and Petroleum Engineering, University of Pittsburgh
Ph.D., Chemistry, California Institute of Technology, 2007

The Keith group applies and develops computational chemistry to study and discover solutions to problems at the interface of engineering and basic science.  They are currently focused on modeling chemical reaction mechanisms and the atomic scale of materials to help develop renewable energy and sustainability technologies.

The group uses quantum chemistry-based multiscale modeling to predict and study the atomic scale of materials and chemical reactions. With electronic structure and atomistic methods, they can investigate fundamental reaction steps at different time- and length-scales that would otherwise be difficult or impossible to investigate with experiment. 

Notably, their studies are entirely carried out in silico (on a computer) and almost entirely free from artificial biases that are present when using experimental inputs. Whether doing so alone or in collaboration with experimentalists, the group provides deep perspective on the atomic-scale of catalytic environments to understand how they work and how to further improve them.

The 'ground-up' multiscale modeling approach uses appropriate levels of quantum chemistry (QC) theory (typically on up to ca. 200 atoms) to model reaction energiesbarrier heightspKas, and standard redox potentials. Using data obtained from QC theory, they can also develop analytic reactive forcefields, which are capable of modeling reaction dynamics on systems on the order of 100,000 atoms. Reactive forcefield data in turn can be used to generate rate constant libraries for kinetic Monte Carlo (kMC) simulations to model larger time-scale and length-scale phenomena such a nanoparticle/material growth and ripening.

Most Cited Publications: 
  1. "The Mechanism of the Wacker Reaction: A Tale of Two Hydroxypalladations," John A. Keith, Patrick M. Henry, Angew. Chem. Int. Ed. 48, 9038 (2009)
  2. "Water Oxidation on Pure and Doped Hematite (0001) Surfaces: Prediction of Co and Ni as Effective Dopants for Electrocatalysis," Peilin Liao, John A. Keith, and Emily A. Carter, J. Am. Chem. Soc. 134, 13296 (2012)
  3. "Theoretical Elucidation of the Competitive Electro-oxidation Mechanisms of Formic Acid on Pt(111)," Wang Gao, John A. Keith, Josef Anton, and Timo Jacob, J. Am. Chem. Soc. 132, 18377 (2010)
  4. "Theoretical Investigations of the Oxygen Reduction Reaction on Pt(111)," John A. Keith, Gregory Jerkiewicz, Timo Jacob, ChemPhysChem 11, 2779 (2010)
  5. "Theoretical Studies of Potential-Dependent and Competing Mechanisms of the Electrocatalytic Oxygen Reduction Reaction on Pt(111)," John A. Keith, Timo Jacob, Angew. Chem. Int. Ed. 49, 9521 (2010)
Recent Publications: 
  1. "A Sobering Assessment of Classical Force Field Methods for Low Energy Conformer Predictions," Ilana Y. Kanal, John A. Keith, Geoffrey R. Hutchison, arXiv:1705.04308
  2. "Nitrogen-doped nanocarbon materials under electroreduction operating conditions and implications for electrocatalysis of CO2," Karthikeyan Saravanan, Eric Gottlieb, John A. KeithCarbon 111, 859 (2017)
  3. "Quantifying solvation energies at solid/liquid interfaces using continuum solvation methods," Corinne M. Gray, Karthikeyan Saravanan, Guofeng Wang & John A. Keith, Molecular simulations 43, 420 (2017)
  4. "Computational investigation of CO2 electroreduction on tin oxide and predictions of Ti, V, Nb and Zr dopants for improved catalysis," Karthikeyan Saravanan, Yasemin Basdogan, James R. Dean and John A. KeithJ. Mater. Chem. A, 2017, Advanced Online
  5. "Explicitly Unraveling the Roles of Counterions, Solvent Molecules, and Electron Correlation in Solution Phase Reaction Pathways," Mitchell C. Groenenboom and John A. KeithJ. Phys. Chem. B 120, 10797 (2016)
Personal | Department
Department of Chemical and Petroleum Engineering, University of Pittsburgh
Ph.D., Chemical Engineering, Cornell University, 1992

The Johnson group tackles fundamental problems over a wide range of subject areas using state-of-the-art atomistic modeling methods. Current projects include CO2 capture through the following methods:

  • Selective adsorption in metal organic frameworks (MOFs).
  • Catalytic nanoparticles on amorphous supports.
  • Multiscale modeling proton-exchange membrane (PEM) based fuel cells.  
  • Hydrogen storage in metal hydrides.
  • Absorption into ionic liquids, including ionic liquids that react chemically with CO2.
  • Physical absorption of CO2 into liquid sorbents.
  • Chemical capture involving carbamate forming amines.
  • Solid-state reactions involving carbonates and bicarbonates.

Tools we use in our studies include Kohn-Sham density functional theory, first principles quantum mechanics methods, classical equilibrium and non-equilibrium molecular dynamics, and Monte Carlo simulation techniques.

Most Cited Publications: 
  1. "The Lennard-Jones equation of state revisited," J. Karl Johnson, John A. Zollweg & Keith E. Gubbins, Molecular Physics 78, 591 (1993)
  2. "Microporous Metal Organic Materials:  Promising Candidates as Sorbents for Hydrogen Storage," Long Pan, Michelle B. Sander, Xiaoying Huang, Jing Li, Milton Smith, Edward Bittner, Bradley Bockrath, and J. Karl JohnsonJ. Am. Chem. Soc. 126, 1308 (2004)
  3. "Molecular simulation of hydrogen adsorption in single-walled carbon nanotubes and idealized carbon slit pores," Qinyu Wang and J. Karl JohnsonJ. Chem. Phys. 110, 577 (1999)
  4. "Rapid Transport of Gases in Carbon Nanotubes," Anastasios I. Skoulidas, David M. Ackerman, J. Karl Johnson, and David S. Sholl, Phys. Rev. Lett. 89, 185901 (2002)
  5. "Adsorption of Gases in Metal Organic Materials:  Comparison of Simulations and Experiments," Giovanni Garberoglio, Anastasios I. Skoulidas, and J. Karl JohnsonJ. Phys. Chem. B 109, 13094 (2005)
Recent Publications: 
  1. "Facile anhydrous proton transport on hydroxyl functionalized graphane," Abhishek Bagusetty, Pabitra Choudhury, Wisssam A. Saidi, Bridget Derksen, Elizabeth Gatto, and J. Karl JohnsonPhys. Rev. Lett. 118, 186101 (2017)
  2. "A comparison of the correlation functions of the Lennard–Jones fluid for the first-order Duh–Haymet–Henderson closure with molecular simulations," J. Karl Johnson, Douglas Henderson, Stanislav Labík, and Anatol Malijevský, Molecular Physics (published online)
  3. "Impact of Support Interactions for Single-Atom Molybdenum Catalysts on Amorphous Silica," Christopher S. Ewing, Abhishek Bagusetty, Evan G. Patriarca, Daniel S. Lambrecht, Götz Veser, and J. Karl JohnsonInd. Eng. Chem. Res. 55, 12350 (2016)
  4. "Predicting catalyst-support interactions between metal nanoparticles and amorphous silica supports," Christopher S. Ewing, Götz Veser, Joseph J. McCarthy, Daniel S. Lambrecht, J. Karl JohnsonSurface Science 652, 278 (2016)
  5. "Cavity correlation and bridge functions at high density and near the critical point: a test of second-order Percus–Yevick theory," Austin R. Saeger, J. Karl Johnson, Walter G. Chapman & Douglas Henderson, Molecular Physics 114, 2516 (2016)

Quantum-Engineered Catalysts that Turn Excess Atmospheric CO2 into Liquid Fuel

  • By Aude Marjolin
  • 8 December 2015

PQI faculty Karl Johnson and his team recently identified the two main factors for determining the optimal catalyst for turning atmospheric CO2 into liquid fuel. The results of the study, which appeared in the journal ACS Catalysis, will streamline the search for an inexpensive yet highly effective new catalyst.

Imagine a power plant that takes the excess carbon dioxide (CO2) put in the atmosphere by burning fossil fuels and converts it back into fuel. Now imagine that power plant uses only a little water and the energy in sunlight to operate. The power plant wouldn't burn fossil fuels and would actually reduce the amount of CO2 in the atmosphere during the manufacturing process. For millions of years, actual plants have been using water, sunlight, and CO2 to create sugars that allow them to grow. Scientists around the globe are now adopting their energy-producing behavior.