MD simulation of Water/Platinum interface
Anirban Roy
Mechanical, Aerospace & Biomedical Engineering Department,
University of Tennessee
This page shows visualizations of the Platinum-Water interface and their interactions.
The development of nanoscale electrochemistry since the mid-1980s has been predominately coupled with steady-state voltammetric methods. This research has been driven by the desire to understand the mechanisms of very fast electrochemical reactions, by electroanalytical measurements in small volumes. Exploration of the behavior of nano-electrochemical structures (viz. nanoelectrodes, nanoparticles, nanogap cells, etc.) of a characteristic dimension "L" using steady-state voltammetric methods generally relies on the well-known relationship, L2 ~ Dt, which relates diffusional lengths to time, t, through the diffusion coefficient, D. Decreasing L, by performing measurements at a nanometric length scales, results in a decrease in the effective timescale of the measurement, and provides a direct means to probe the kinetics of steps associated with very rapid electrochemical reactions, such as gas evolution reactions. However, these experimental setups tend to be expensive and highly complex. Therefore, accurately simulating such phenomenon is of immense interest.
Nanobubble nucleation is a problem that affects efficiency in electrocatalytic reactions since those bubbles can block the surface of the catalytic sites. The final goal of this two part project will be to simulate such a phenomenon and validate the results with the work carried out by White, H. and his research group at University of Utah. They have carried out electrochemical measurements of the nucleation rate of individual H2 bubbles at the surface of Pt nanoelectrodes (radii between 7 to 41 nm) that were then used to determine the critical size and geometry of H2 nuclei leading to stable bubbles.
In this project, we have reproduced the work[1] by Spohr, E., which simulates the interaction between water and platinum at their interface where the barriers for surface diffusion and reorientation of a single water molecule on the quadratic (100) face of the face-centered-cubic platinum crystal are discussed. In this work, it is also shown that orientational structure of water is strongly influenced by water-water interactions and is considerably different from the preferential orientation according to the water-platinum interaction potential. We have also investigated the effect of temperature on these structural orientations of water at the interfacial surface.
Color Legend: References
[1] Spohr, E., Computer simulation of the water/platinum interface. The Journal of Physical Chemistry, 1989. 93(16): p. 6171-6180 doi: 10.1021/j100353a043 posted: March 2020.Interactive Structures
updated: March 2020.