Hard-templating of carbon using porous SiO2 monoliths revisited - Quantitative impact of spatial confinement on the microstructure evolution

摘要

Hard-templating of porous SiO2 is one of the major approaches for the synthesis of porous carbons, frequently utilized in separation/adsorption as well as in energy storage applications. A high degree of structural order on the atomic scale, i.e. size and the disorder of the carbon microstructure is desirable, which is closely related to physical and chemical properties such as the electrical/thermal conductivity and the corrosion resistance. Usually, the evolution of the carbon microstructure is known to be foremost dominated by the chemical nature of the precursor and the applied heat-treatment. This work for the first time quantitatively examines the influence of spatial confinement on the microstructural development experienced throughout the nanocasting process in monolithic meso-macroporous SiO2, by employing an advanced evaluation approach for wide-angle X-ray scattering data of non-graphitic carbons. The hard-templating process was characterized by SEM, mercury intrusion porosimetry and N-2-physisorption, revealing that the carbon precursor is exclusively located within the mesopores of the templates. The structural characterization of the obtained porous carbons showed that the size and disorder of the graphene stacks is massively influenced by the spatial confinement during the nanocasting process, proving that spatial restrictions are an important synthesis parameter and need to be carefully considered. (c) 2017 Elsevier Ltd. All rights reserved.