Deposition of poly(furfuryl alcohol) in mesoporous silica template controlled by solvent polarity: A cornerstone of facile and versatile synthesis of high-quality CMK-type carbon replicas. Nanocasting of SBA-15, SBA-16, and KIT-6
Rafał Janus, Piotr Natkański, Mariusz Wądrzyk, Marek Lewandowski, Marek Michalík, Piotr Kuśtrowski
Abstract
Six CMK-n replicas (n = 3, 5, 6, 7, 8, and 9) were synthesized using a new, facile and versatile method based on a surface-selective deposition of poly(furfuryl alcohol) onto the silica matrix. The concept of the synthesis relies on the in situ polycondensation of the carbon precursor in a toluene suspension of the hard template. Preferential pre-adsorption of the monomer onto silica provides even coverage of its surface with polymer, which is a prerequisite to the formation of highly ordered carbon negative structures (either hollow- or rod-type). The procedure is operated under ambient pressure and at moderate temperature, and a preliminary modification of silica and vacuo carbonization are no longer needed. A systematic study on materials (SEM, TEM, XRD, N2, and Ar adsorption) evidenced that the proposed pathway offers the preparation of carbon mesostructures featuring excellent structural and textural parameters while maintaining the morphology of the mother silica. CO2 adsorption revealed inhomogeneous porosity of the carbonaceous material itself. The rod-type replicas showed a core-shell structure, in which each carbon rod was built of the outer nonporous shell enveloping the microporous core. In contrast, the hollow-type carbons were constituted of non-microporous turbostratic carbon.