More Accurate Modeling of Electrochemistry Using Grand Canonical Quantum Chemistry
Including the applied potential in quantum chemical models of electrochemical processes is challenging. Early attempts avoided this challenge by altogether ignoring the applied potential, but this neclects the central role played by the applied bias in driving electrochemistry. Later efforts approximated the effects of the applied bias on the energetics of the reaction using the elegant Computational Hydrogen Electrode model, which shifts the free energies of intermediates that react by the addition or removal of a proton and electron pair. However, this approximation fails for many cases, especially those where the field changes the geometry of a reacting adsorbate, the electronic structure of the reactive site and where the intermediate steps are not equivalent to a transfer of an electron-proton pair.
In this talk I will describe the results of using grand canonical density functional theory (GC-DFT), which explicitly includes the applied potential, to model several electrocatalytic processes, including ammonia synthesis by biomimetic Chevrel phase materials , and CO2 reduction by single transition metal nitrogen doped graphene , metal phosphides  and metals . I will compare our results to those of the CHE model and to experiment. In each case we find that GC-DFT provides a richer and more accurate picture of electrochemistry, which is not only necessary for more fully understanding these complex processes, but which also enables quantum chemists to rationally design new electrocatalysts.
 Singstock, R.R., and C. B. Musgrave, “How the Bio-Inspired Fe2Mo6S8 Chevrel Breaks Electrocatalytic Nitrogen Reduction Scaling Relations,” Journal of the American Chemical Society, 144 (28), 12800-12806 (2022). DOI: 10.1021/jacs.2c03661
 Brimley, P., A. Hussain, A. Alherz, Z. Bare, Y. Alsunni, W. Smith, and C. Musgrave, “The Effect of the Applied Potential on the Electrochemical Reduction of CO2 to CO over MN4C Electrocatalysts Using Grand-Canonical Density Functional heory,” ACS Catalysis, 12, 10161-10171 (2022). DOI: 10.1021/jacs.2c03661
 Calvinho, K., K. Yap, A. Alherz, A. Laursen, S. Hwang, Z. Bare, C. Musgrave*, G. Dismukes*, “Surface Hydrides on Fe2P Electrocatalyst Reduce CO2 at Low Overpotential: Steering Selectivity to Ethylene Glycol,” Journal of the American Chemical Society, 143 (50) 21275-21285 (2021). DOI: 10.1111/jace.18310
 Alsunni, Y., A. Alherz, Z. Bare, C. Musgrave, “Electrocatalytic Reduction of CO2 to CO over Ag(110) and Cu(211) Modeled by Grand-Canonical Density Functional Theory,” Journal of Physical Chemistry C, 125 (43) 23773-23783 (2021). DOI: 10.1021/acs.jpcc.1c07484
Hosted by Professor Charles Dismukes