(217eg) Computer Simulations of Fluid Flow Over Catalytic Surfaces for Water Splitting

Artificial photosynthesis is a growing field of science with multiple applications including the generation of electricity and production of hydrogen. A heterogeneous approach to generating hydrogen is the photocatalytic water splitting at electrodes, where metal catalysts embedded in semiconductors serve as reactive surfaces for water adsorption and decomposition into oxygen and protons. We develop a reduced representation of the system via the flow of a fluid composed of water and ions over a solid surface of close packed particles with embedded metal catalysts. To investigate the transport phenomena that can arise from such electrochemical reactions, coarse-grained molecular dynamics simulations using the LAMMPS package are utilized to predict the nanoscale behavior of the system. The goal is to observe and characterize the adsorption dynamics of the fluid mixture to the metal catalysts through the measurement of properties such as diffusion coefficients, velocity profiles, radial distribution functions, and mean residence times. Our objective is to gain a better understanding of the transport phenomena to explain the kinetics and thermodynamics of the processes occurring during the flow of reactants over a catalytic surface using molecular dynamics simulations. These simulations can identify the role of molecular scale properties on the catalytic process, thereby allowing predictions of the water splitting performance. These investigations have the potential to be applied to other chemical processes that make use of fluid reactions with embedded catalysts on the support.