Characterization of porous solids by NMR

Abstract

A new simple and rapid method to determine pore size distributions is described which employs a simple nuclear magnetic resonance (NMR) apparatus. The method exploits the depression of the melting point of a crystalline solid confined within a pore, which is dependent on the pore diameter. The melting point distribution is determined by analyzing the NMR signal as a function of temperature. The technique is demonstrated by application to porous silicas and is shown to give pore size distributions comparable to those obtained by the conventional gas desorption method for pore sizes in the range 5 to 50 nm.