Assessing the Impact of Point Defects on Molecular Diffusion in ZIF-8 Using Molecular Simulations.

Because defects are ubiquitous in materials, they may play an important role in affecting the performance of materials in practical applications. Here, we investigate the influence of point defects on the diffusion of molecules including water, hydrocarbons, and acid gases in zeolitic imidazolate framework-8 (ZIF-8) using molecular simulations. To make these simulations possible, we introduce a force field that extends previous descriptions of pristine ZIF-8 to include experimentally relevant point defects. In general, the point defects we examined increase the local hopping rate for molecular diffusion, suggesting that low concentrations of these defects will not dominate long-range molecular diffusion in ZIF-8.