Four CRC-affiliated faculty were awarded the National Science Foundation (NSF) CAREER Award this funding cycle. The CAREER Award is the NSF’s most prestigious award for early career-development for teacher-scholars, and has a reviewing and selection process that is one of the most competitive within NSF. The Pitt CRC faculty who received the CAREER Award this cycle are John Keith, Peng Liu, Giannis Mpourmpakis and Christopher Wilmer. Remarkably, three of the faculty, Keith, Mpourmpakis and Wilmer, all come from a single department within the Swanson School of Engineering (Chemical & Petroleum Engineering). All four faculty rely heavily on CRC resources to perform their research and all contributed startup funds to access the high-levels of computer time and support required to make their research a success. The role that CRC plays in facilitating their research is illustrated by this quote from Dr. Mpourmpakis: “CRC has been very instrumental in accelerating our research both in terms of available computational resources and support from experienced personnel.”
Descriptions of each of the CAREER research projects are given below.
John A. Keith, Assistant Professor and Inaugural R.K. Mellon Faculty Fellow in Energy SusChEM: Unlocking local solvation environments for energetically efficient hydrogenations with quantum chemistry (#1653392)
John Keith’s proposal “Unlocking local solvation environments for energetically efficient hydrogenations with quantum chemistry” was recently selected for an NSF CAREER award. The project addresses the production of carbon-neutral liquid fuels via electrocatalytic reduction of the greenhouse gas carbon dioxide (CO2) to methanol. Specifically, the study seeks to improve the efficiency and selectivity of current solvent-based electrochemical processes by advancing understanding of how aqueous electrolytes participate in the overall reaction mechanisms at the atomic scale. The research will be coupled with educational thrusts that engage students in grades 8-12 in learning about renewable energy catalysis and computational chemistry.
In the figure shown above, A) overlaid Pourbaix diagrams for an N-doped graphene ribbon (gray/purple) and carbonic acid (solid lines). B) QC calculated ΔE values along the reaction pathway for the hydride transfer reaction: 2H2O + BH4– + CO2 →H3O+ +BH3OH– + HCO2–. PBE data corresponding to minimum energy pathways for a) explicit solvent + counter ion, b) continuum solvent only, c) 1st solvent shell + continuum solvent, d) counter ion and continuum solvent, e) 1st solvent shell + counter ion + continuum solvent.
Peng Liu, Department of Chemistry
Computational Studies of Transition Metal Catalyzed Reactions in Organic Synthesis (#1654122 )
In this CAREER project funded by the Chemical Structure, Dynamic & Mechanism-B Program (CSDM-B) of the Chemistry Division, Professor Peng Liu of the Department of Chemistry at the University of Pittsburgh is developing new strategies to use computational tools to investigate mechanisms and effects of ancillary ligands in transition-metal-catalyzed reactions of unactivated starting materials, such as C-C and C-H bonds, and unactivated olefins. The goal of this research is to reveal the fundamental reactivity rules of common organometallic intermediates in these transformations and to develop new models to interpret ligand effects on reactivity and selectivity. This proposal’s educational and outreach plan aims to maximize the power of computations to enhance learning of organic chemistry concepts and to facilitate synthetic organic chemistry research. Professor Liu’s team will develop virtual reality (VR) software and educational materials to visualize three-dimensional molecular structures and reaction mechanism videos in an interactive and immersive environment.
This project aims to address two basic challenges in performing computational studies on transition-metal-catalysis: 1) the lack of mechanistic understandings in many recently developed catalytic systems, and 2) the complexities in analyzing and rationalizing computational data, in particular, the origin of ligand effects. The proposed research will investigate novel reaction pathways involving the activated organometallic intermediates formed after the C-H and C-C bond cleavage steps, and elucidate the effects of ligands, directing groups, substituents, ring strain, and norbornene and Lewis acid co-catalysts. To systematically characterize the origin of ligand effects on reactivity and selectivity, a ligand-substrate interaction model will be developed. This model uses energy decomposition analysis (EDA) methods to dissect the through-space ligand-substrate interactions into chemically meaningful terms, including steric repulsion, polarization, charge transfer, and dispersion. The insights obtained from the proposed ligand-substrate interaction model will be used to develop of a catalyst screening methodology for transition-metal-catalysts.
Giannis (Yanni) Mpourmpakis, Assistant Professor
Designing synthesizable, ligand-protected bimetallic nanoparticles and modernizing engineering curriculum through computational nanoscience (#1652694)
“The goal of this project is to develop a novel open-access computational framework for predicting the growth mechanisms and morphologies of ligand-protected metal nanoparticles (NPs).
With NPs impacting numerous fields of science and technology, from energy to medicine to the environment, there is a critical need to determine the growth mechanisms of ligand-protected metal NPs and predict NP morphologies that can be synthesized in the laboratory. Although metal nanoparticles (NPs) of different sizes and shapes can be synthesized by colloidal chemistry methods, advances towards controlling NP morphology have been based largely on trial and error experimentation, which is often tedious and costly. The proposed computational framework will employ novel first-principles-based structure-property relationships accounting for structure sensitivity and metal composition. The integration of research and education efforts will focus on modernizing the traditional Chemical Thermodynamics course by introducing animation modules based on cutting-edge nanotechnology examples. Outreach activities are planned through a nanoscale-inspired interactive computer game to engage high school students, including underrepresented minorities, into pursuing STEM careers and increase awareness about the importance of the field of nanotechnology.
The proposed research project will combine Density Functional Theory methods with Monte Carlo and Molecular Dynamics simulations, Machine Learning, and scientific computing to develop a novel, open-access computational framework, applicable to the design of ligand-protected NPs. This framework will generate a library of crystal structures and electronic properties of thermodynamically stable, thiolate-protected, Au-based bimetallic NPs, across a range of heterometals and particle morphologies, all under realistic experimental conditions. The proposed work aims to advance current theories on NP stabilization, which are based on simplified, electron counting rules. The proposed computational framework will enable rational design of ligand-protected NPs. It will also elucidate NP growth steps that are experimentally intractable, thus accelerating nanomaterials discovery. The research findings will be made available online for experimental verification.”
Christopher Wilmer, Assistant Professor
Fundamental limits of physical adsorption in porous materials (#1653375)
, such as post-combustion carbon capture. The PI will use classical molecular modeling to simulate adsorption in randomly generated porous materials, called pseudomaterials, where the constraint that the materials be energetically stable is relaxed. Since the limits of adsorption in pseudomaterials will necessarily be higher than in real materials, determining the limits of pseudomaterials will also determine the limits for real materials. This approach will be used to establish a rigorous theoretical upper limit on the efficiency of a membrane-based post-combustion carbon capture process, which is considered one of the most promising technologies for mitigating climate change due to fossil fuel-based power plant emissions.”