Exploring Crystal Morphology of Nanoporous Hosts from Time-Dependent Guest Profiles

摘要

Nanoporous materials are key to a plethora of modern technologies and decisively contributed to the present boom in the development of heterogeneous catalysis and molecular sieves.In these applications,knowledge of the details of mass transport often turns out to be crucial for the exploration of routes for their use and further optimization.It was common practice to apply Fick's 1st law to analyze the rate of molecular uptake or release following a change in the pressure of the surrounding atmosphere.This approach,however led to much smaller effective diffusion coefficients,which could only be attributed to the existence of transport resistance on the external surface of the crystal (that is,surface barriers,there are numerous models concerning their origin).In addition there could be other barriers within the pore system of the zeolite bulk phase,acting in addition to the transport resistance.