Composite materials: Textural characteristics

Abstract

Calculation of pore size distribution of complex materials needs special approaches. • Self-consistent regularization is effective tool to analyze data for complex materials. • Model with slit/cylindrical pores and voids between nanoparticles is appropriate for composites. • The SCV/SCR method gives better results than NLDFT or QSDFT for composites. A self-consistent regularization (SCR) procedure applied to integral adsorption equations based on a complex model with slit-shaped and cylindrical pores and voids between spherical nonporous particles packed in random aggregates (SCV model) for two or three types of components (activated carbon, carbon black, silica gel, fumed silica) in composites gives more clear pictures of pore size distributions (PSD) than nonlocal density functional theory (NLDFT) or quenched solid DFT (QSDFT) methods. Results of this approach for individual adsorbents are comparable with the results of NLDFT or QSDFT methods using complex pore models (slit/cylindrical or slit/cylindrical/spherical pores). The SCV/SCR method is useful to study the textural features of hybrid materials, the PSD of which is difficult to be calculated using standard approaches. The PSD of complex materials can also be estimated using (1) high-resolution microscopic methods ( e.g. HRTEM) with software (Fiji/ImageJ) used for quantitative treatment of images; (2) cryoporometry based on low-temperature 1 H NMR spectroscopy; and (3) small angle X-ray scattering (SAXS). Results of these methods can effectively amplify results of the standard adsorption methods.