Metal Nanoparticles for Electrocatalysis
Structural models of unrelaxed Pt NPs of increasing size (up to ∼2,000 atoms) at 600 K with a 1 ML coverage of oxygen adsorbates (top). Snapshots of the time-evolved NPs after 3.2 ns of MD simulations with the atoms color-coded by the local distribution of the excess surface charge according to the given scale (bottom). The (110) facet NPs are labeled with a prime after the number of Pt atoms in the NP.
Investigation of metallic nanoparticles. Project is funded by the Department of Energy, Basic Energy Sciences. Carried out in collaboration with Prof. Ismaila Dabo. The focus of this project is investigating the structural and dynamical evolution of metallic nanoparticles and bimetallic nanoalloys under conditions consistent with their use in electrocatalytic applications, including oxidation effects on metal migration and the dissolution of these nanoparticles at solid-liquid interfaces. The focus is on Pt, which is an active electrocatalyst and is typically combined with other metals to maximize productivity while minimizing cost. A significant area of recent research has been the design of electrodes that are stable in corrosive environments and can withstand large voltages and one way of doing this is to use core–shell electrocatalyst where the active component is present as a thin shell on a core metal support. Such core–shell catalysts may be subject to metal migration where the catalytically active shell components diffuse into the core (thereby reducing the concentration of active sites along the surface) or may undergo metal dissolution where catalytically active components dissolve into the electrolyte (thereby diluting the number of sites available for electrocatalysis). Understanding the conditions under which nanoalloy electrocatalysts degrade is an essential requisite for designing durable electrochemical cells and is the focus of this effort. A combination of computational methods is being applied to the problem, including density functional theory calculations, classical molecular dynamics simulations with reactive potentials, and cluster expansion modeling.
Students working on projects in this area are Stephen Holoviak and Lingxiao Mu.
Publications:
“Atomic-scale modeling of the dissolution of oxidized platinum nanoparticles in an explicit water environment”, R.E. Slapikas, I. Dabo, S.B. Sinnott, J. Mater. Chem. A 2023 11(13), 7043-7052. DOI: https://doi.org/10.1039/D2TA09152F
“Surface reconstruction of oxidized platinum nanoparticles using classical molecular dynamics simulations”, R. Slapikas, I. Dabo, S. B. Sinnott, Computational Materials Science, 2022, 209. DOI: https://doi.org/10.1016/j.commatsci.2022.111364
“Quantifying multipoint ordering in alloys”, J.M. Goff, B.Y. Li, S.B. Sinnott, I. Dabo, Phys. Rev. B 2021 104(5), 054109. DOI: https://doi.org/10.1103/PhysRevB.104.054109
“Effects of surface charge and cluster size on the electrochemical dissolution of platinum nanoparticles using COMB3 and continuum electrolyte models”, J. M. Goff, S. B. Sinnott, I. Dabo, J. Chem Phys. 2020, 152 (064102). DOI: https://doi.org/10.1063/1.5131720