A molecular model for carbon black primary particles with internal nanoporosity

A molecular model of primary particles of porous carbon black has been developed. Using the hexagonal graphite sheets as building units, we simulated formation of carbon particles consisting of a core–shell structure. Several structural properties of carbon were examined. Graphite layers arrange in a concentric fashion in the shell region near the external surface of carbon. This trend gradually diminishes toward the center of carbon particles, resulting in an amorphous characteristic in the core region. In line with XRD experiments, our simulations show that about half of the graphite sheets in the carbon shell form microcrystalline domains typically consisting of 2–5 layers with a broad interlayer spacing of 0.34–0.4 nm. Starting from nonporous carbon particles with a high density of 2 g/cm3, a ‘digging’ approach was further developed to particularly model the internal nanoporosity of mesoporous carbon materials that are often obtained by the silica templating technique. The validity of the modeling technique to generate pores inside carbon particles is discussed in view of reproducing targeted PSDs.