Séminaire de Stephan Steinmann (Laboratoire de Chimie, ENS de Lyon)
Molecular Mechanics for Metal-Water Interactions : Force Field Development and Solvation Free Energies
le vendredi 8 janvier 2021 à 11h (en visio-conférence)
Résumé
Electrocatalysis is at the heart of energy conversion devices such as fuel cells and solar cells or electrolyzers powered by « excess » electricity. These applications have in common that they take place a highly complex interface between the (metal) electrode and a solution that contains a high-dielectric solvent with a high concentration of ions. Furthermore, the surface charge is tuned in order to impose the electrochemical potential. When modelling such systems from first principles in periodic systems, a neutralizing counter charge needs to be introduced, which physically represents the electrical double layer. An attractive solution is the Poisson-Boltzmann (PB) equation, which reduces the environment (solvent and electrolyte) to an easily computable mean-field which can be included in the DFT computations and thus be used for practical applications [1,2]. Nevertheless, the underlying continuum solvation model has major shortcomings, as chemical interaction between the solvent and the surface is not well reproduced. This can, however, be improved upon by moving to a molecular description of the solvent. Due to the high computational cost and slow diffusion at the solid/liquid interface, these atomistic simulations need to be carried out at the molecular mechanics level of theory. However, an accurate force field is a prerequisite for such investigations. Here, I will describe our recent efforts to reach a realistic description of the water-noble metal surface interaction via a classical force field [3,4] and the limitations of such an approach in the absence of many-body (polarization and charge-transfer) interactions [5,6]. Finally, the solvation energies obtained with our water/Pt(111) force field for benzene and phenol adsorption are compared to experimental estimates, showing a semi-quantitative agreement [7].
References
[1] Steinmann and Sautet J. Phys. Chem. C 2016, 120, 5619.
[2] Abidi, Bonduelle-Skrzypczak and Steinmann ACS Appl. Mater. Interfaces, 2020, 12, 31401.
[3] Steinmann, Ferreira de Morais, Goetz, Fleurat-Lessard, Iannuzzi, Sautet and Michel J Chem Theory Comput. 2018, 14, 3238.
[4] Clabaut, Fleurat-Lessard, Michel and Steinmann J. Chem.Theory Comput. 2019, 16, 4565.
[5] Staub, Iannuzzi, Khaliullin and Steinmann J. Chem.Theory Comput. 2019, 15, 265.
[6] Clabaut, Staub, Galiana, Antionetti and Steinmann J. Chem. Phys. 2020, 153, 054703.
[7] Clabaut, Schweitzer, Goetz, Michel and Steinmann J. Chem.Theory Comput. 2020, 16, 6539.
