NSF-DFG Echem: Synergistic Experimental and Computational Approaches to Designing Electrocatalysts with Proton-Responsive Ligand Architecture

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Storing and releasing energy in chemical bonds using non-petrochemical small molecules is attractive because of its scalability, stability, and flexibility for short-term or long-term deployment. Coaxing non-precious metals to catalyze reactions under abiotic conditions while replicating the activity and efficiency of enzymes remains a challenge in the arena of fundamental chemical science. Accurately benchmarking and predicting the properties of new catalysts for chemical energy storage requires experimentalists and theorists to work together so new tools become accessible to the broader chemistry community. This program benefits from a unified experimental and theoretical approach to tackle modern challenges with global impact.Some enzymes use a pendant base attached to the catalyst framework, enhancing proton transfer rates and efficiencies during H2 production. Using these templates as inspiration for making synthetically tractable molecular electrocatalysts, synthesis will focus on coordinating amine-functionalized cyclopentadienyl ligands to non-precious metals, which are unprecedented in electrocatalysis. The impact of primary/secondary coordination spheres on electrocatalytic H2 production will be investigated in detail using spectroscopic and electroanalytical methods. Characterization and mechanistic analysis will be tightly coupled with computational datasets to guide laboratory efforts.Electrocatalyst performance will be assessed by measuring redox potential, turnover frequency, overpotential, and probing scaling relationships. Experimental and computational analyses will survey the free energy landscapes of electrocatalysts by calculating M-H/N-H/C-H redox potentials and acidities. These parameters will guide synthetic efforts and predict which catalyst modifications could minimize free energy differences between intermediates. State-of-the-art quantum chemical methods will be used, including automatic screening for conformers, treatment of solvation effects, and semi-automated reaction-network exploration tools. The development and maturation of computational methods will benefit greatly from their application to these mechanistic challenges.Broader themes such as sustainability drive the science forward, using Nature as inspiration to bring renewable energy closer to reality for society. The development of (semi)automated computational workflows will aid chemists to apply similar workflows to their problems on standard desktop computers instead of supercomputers.