(766d) DFT Analysis of Amino Acid Functionalization of Hematite for Electroreduction Catalysis

In a future with plentiful renewable electricity, electro-chemical systems to carry out chemical transformations can provide an efficient and sustainable alternative to fossil-fuel based energy consumption. Several important chemical reactions, such as CO₂ and N₂ reduction, have electro-chemical counterparts to form useful products through a series of proton-coupled electron transfer (PCET) reactions. The activity and selectivity of PCET reactions can significantly be impacted by the electrode-electrolyte interfacial properties, and tuning this near-surface environment can be used as a control towards developing active and selective electrochemical conversions. Surface-bound amino acid chains can be used to alter the electrocatalytic performance by altering the active site structure and local environment. We used Density Functional Theory (DFT) to study the surface binding of short amino acid chains on Fe₂O₃ surfaces to understand how they alter the interfacial environment through surface-ligand interactions. We examine the effects of small amino acid binding on the stability of different Fe₂O₃terminations in the electrochemical environment. We consider how presence of continuum solvation affects the binding preferences of the amino acid. Coverage effects on binding energies are also evaluated. We then examine how these amino acid or peptide chain can act as shuttling agents to alter the energetics and kinetic barriers of PCET reactions.