Surface and pore structures of CMK-5 ordered mesoporous carbons studied by nitrogen adsorption and surface spectroscopic methods

Abstract

This chapter describes the surface and pore structures of CMK-5 ordered mesoporous carbons investigated by nitrogen adsorption and surface spectroscopic methods. The matrices used for the ordered mesoporous carbons (OMC) synthesis were characterized by nitrogen adsorption. The OMCs were studied by X-ray photoelectron spectroscopy (XPS) and by nitrogen adsorption. The X-ray diffractograms of the SBA-15 aluminosilicates showed intense narrow diffraction lines, indicating highly ordered structures. The Si/Al ratio only had a minor influence. It should be considered, however, that extra-framework aluminum species, possibly present in the pores, would not cause new X-ray diffractions to appear. Extra-framework species may narrow the pore diameter or block sections of the pore system. The mesopore volume and surface area of the aluminosilicates decreased indeed significantly with decreasing Si/Al ratio. If during the OMC synthesis the entire pore system of the matrix is filled with the carbon product, the OMC can be described as a network of carbon rods. However, it is also possible to form the carbon product only on the pore walls of the matrix, without filling the entire pore. The produced CMK-5 OMCs consist of a network of nanopipes. The pore size distribution (PSD) of the CMK-5 OMCs showed the presence of two types of mesopores