Standard Nitrogen Adsorption Data for Characterization of Nanoporous Silicas

The nitrogen adsorption isotherm measured at 77 K in the relative pressure range from about 5 × 10-7 to 0.988 for a macroporous silica is reported in a tabular form. The isotherm data are in good agreement in the high-pressure range with the reference data published by Gregg and Sing and by Kiselev and Aristov and provide an extension of the latter data to the low-pressure region, for which a reliable reference isotherm was not availalable in the literature. Application of the currently reported reference adsorption isotherm is discussed. The data can be used in comparative analysis (αs-plot or t-plot) to evaluate the external surface area, micropore volume, primary mesopore volume, and total surface area as well as to analyze surface properties of silica-based materials. The adsorption isotherm can also be applied as a statistical film thickness curve in the calculation of the mesopore size distribution.