(Invited) Structural Characterization of Nanoporous Materials Via Gas Sorption

Recently, much effort has been devoted to the development of nanoporous materials which exhibit hierarchical pore structure with the appropriate balance of micro- and mesopores, as well as advantageous pore connectivity. The network of interconnected micro- and mesopores facilitates efficient transfer of fluids to and from active sites within and through the material, leading to benefits in numerous applications. Detailed insights into the pore architecture (pore size distribution, pore volume, and pore interconnectivity) are important because they control transport phenomena, diffusional rates, and govern selectivity. Gas sorption is well suited for this because it assesses a wide range of pore sizes, spanning the entire micro- and mesopore range. Additionally, an in-depth characterization of the pore network can also be obtained with a detailed understanding of the adsorption and phase behavior of fluids confined in such complex pore structures. Here, we discuss recommended experimental and state-of-the-art data reduction methods for a comprehensive study of the pore architecture of nanoporous materials which includes: choice of adsorptive, accurate BET area calculation, DFT for pore size and volume determination, hysteresis scanning, and interpretation of material phase transitions. Recent examples of the structural characterization of novel carbons, mesoporous zeolites, and MOFs will be discussed.