CAREER: SusChEM: Unlocking local solvation environments for energetically efficient hydrogenations with quantum chemistry

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

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. The focus of the study will be to integrate high-level electronic structure theory, molecular dynamics, and machine learning to quantitatively understand how interactions between solvent molecules, salts, and co-solutes (i.e. "local solvation environments") regulate fundamental mechanisms of CO2 reduction (CO2R) into fuels. Four basic scientific questions will be addressed related to CO2R in the presence of aromatic N-heterocycles, here studied in the form of molecules and as nitrogen-doped carbon electrodes. These are 1) the identification of the most likely chemical functionalities (i.e. Lewis base, Brønsted acid, H-atom donor, hydride donor) that participate in energetically efficient CO2R into methanol; 2) quantitative predictions of the free energy barriers for different CO2 hydrogenation processes in different local solvation environments; 3) refined understanding of the level of computational modeling needed to reliably predict hydrogenation thermodynamics and kinetics in realistic electrochemical environments; and 4) generalized insight into the degree to which local solvation environments can be tuned to enhance the conversion of low-value carbon-containing feedstocks to liquid fuels. Graduate and undergraduate students will develop educational modules that combine concepts in renewable energy and introduce computational chemistry modeling. These modules will then be tested to determine their capacity to engage and excite students in the Pittsburgh Public School District about opportunities in STEM fields.