Comprehensive Structure Analysis of Ordered Carbon Nanopipe Materials CMK-5 by X-ray Diffraction and Electron Microscopy

Abstract

The structure of ordered mesoporous carbon materials CMK-5 was analyzed in detail by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis by applying the recently developed continuous density function technique. The materials present two-dimensional (2-D) hexagonally ordered arrays of carbon nanopipes formed within the mesopores of SBA-15 silica templates used for their fabrication. The series of CMK-5 carbons were synthesized by applying the templates of different pore widths and two carbon precursors: furfuryl alcohol and acenaphthene. All the materials were well-ordered, exhibiting five distinct XRD reflections, high nitrogen BET specific surface areas (about 2500 m2/g), and large pore volumes (about 2 cm3/g). TEM analysis and XRD modeling allowed precise determination of the mesostructure characteristics such as the nanopipe diameter, wall thickness, and shape. Around 15% of the space between the nanopipes was found to be occupied by carbon interconnections formed inside the complementary pores of the SBA-15 templates. The structure parameters determined correlated well with the synthesis procedures and were fully consistent with the nitrogen adsorption and thermogravimetric data. The differences in the properties and the formation mechanisms of the materials synthesized by applying furfuryl alcohol and acenaphthene carbon precursors were analyzed based on the whole scope of data obtained.