Structural Characterisation of Hierarchically Porous Silica

Monolith by NMR Cryo-porometry and -diffusometry

Abstract

A systematic NMR cryo-porometry and -diffusometry study using nitrobenzene as a probe liquid is carried out in order to characterise pore structures of hierarchically-organised porous silica monolith possessing mesopores along with a 3D bicontinuous macropore network. The result obtained from NMR cryoporometry shows the presence of a relatively wide mesopore size distribution of 10-35 nm. Furthermore, NMR cryodiffusometry indicates that whilst the mesopores are highly tortuous (T_meso ≈6), they have little influence on the overall tortuosity of the material (T_macro ≈1.5), which is largely dominated by the macropores (T_overall ≈1.7).