Diffusion in nanoporous materials is a fascinating topic of great practical relevance, e.g., for catalytic and molecular separation processes. Despite decades of intensive experimental and theoretical work, there are still gaps in our understanding of diffusion fundamentals. Recent insights into which processes limit the overall transport in porous materials could influence the design criteria and the operation of important processes that apply nanoporous materials, including those for environmental processes relevant to sustainable development – from increasing product selectivity in catalysis and membrane separations, to materials for electrochemical devices and biomedical engineering. Such insights result from more sophisticated experimental characterisation tools and molecular simulations, but also progress in materials synthesis.
Diffusion in ordered, uniform microporous materials with strong nanoconfinement effects has been extensively studied, e.g., in zeolites, metal organic frameworks and carbon nanotubes. Most materials, however, are heterogeneous, and this introduces surprises that matter in applications. In the seminar, Prof. Coppens will discuss the impact of heterogeneity and nanoconfinement on molecular transport and reactions, with examples including enzymes in nanoporous silica, Knudsen diffusion in amorphous alumina with its fractal rough surface, and surface barriers in zeolite crystals. Further exploring how heterogeneity can be embraced, how thinking holistically across length scales is essential, and how nature can teach us lessons to design better catalysts, adsorbents, and membranes.