Molecular-Level Insights into Adsorption and Diffusion Properties of CO and CO₂ on Pt-Supported Graphene

The adsorption and diffusion of gas molecules in heterogeneous catalytic reactions are greatly influenced by various factors such as temperature, pressure, and catalyst microstructures. To clarify the role of controlling factors, the adsorption and diffusion behaviors of CO2 and CO in the supported Pt system were investigated by multi-scale simulation. The adsorption number of molecules and adsorption energies calculated by molecular dynamics and density functional theory, respectively, indicate that Pt has a stronger adsorption for CO. The difference in the adsorption number is proportional to the number of adsorption sites and has a volcanic relationship with temperature. The diffusion coefficient of CO molecules varies more dramatically with temperature. Furthermore, the generalized formula related diffusion coefficient with temperature, pressure, and surface atom number of nanoparticles was further validated based on simulation data. This work provides insights into the diffusion modulation of gas molecules via the structural design of catalysts and regulation of reaction conditions.