Synthesis of a carbon monolith with trimodal pores

Abstract

Mesoporous carbons are of great importance in a variety necessary to fabricate them in macroscopic shapes. Carbon of fields such as catalysis, separation, energy storage, and monoliths with mesopores have been synthesized by Zhao electrode materials because they have a high specific et al. [14] and Sayari et al. [15]. However, shrinkage or surface area, large pore volume, good mechanical stability cleft was usually observed for their resulting products, and chemical inertness. Therefore, synthesis of mesoporprobably due to the lack of mechanical stability of the ous carbons with a narrow pore size distribution is template and the big capillary pressure [16]. Furthermore, currently receiving considerable attention. A templating no textural pores exist in the products, which severely method using appropriate materials has been successfully restrict their application in separation, purification etc. employed for the purposes [1–4]. Ryoo and co-workers A silica monolith, which was prepared by Nakanishi et [4–7] first reported the synthesis of ordered mesoporous al. [17] via the combination of phase separation and carbons of the CMK family using ordered mesoporous sol–gel processes, exhibits both co-continuous structure silica particles as templates. Pinnavaia et al. [8] have and mesoporosity; the co-continuous structure results from prepared a hexagonal mesostructured carbon molecular the interconnected silica skeletons and the interconnected sieve (C-MSU-H) using a silica with meso-ordered structextural pores with their size in the micrometer range, ture (MSU-H) as a hard template. In addition to these while the mesopores exist in the silica skeleton surface ordered mesoporous carbons, some worm-like or disorwith the pore size in the nanometer scale. Furthermore, the dered porous carbons were also reported. Hyeon and coshape and macropore /mesopore size of the silica monolith workers [9,10] demonstrated that mesoporous carbons is easily controlled by the adjustment of the preparation could be prepared using silica sols as templates. However, conditions. The unique property of the silica monolith due to the dispersion character of silica sols, the mesopores itself presents an attracting template for carbon replica. in the final carbons were discrete, which severely limited Here, we report the synthesis of a carbon monolith with their applications [9,10]. Recently, mesocellar silica foam co-continuous structure and trimodal pores by a templating (MCF) and very large pore hexagonal and cellular foammethod using a novel silica monolith as the template. The like molecular sieve silica with well cross-linked frameresultant carbon monolith is characterized by high surface work walls (MSU-F) were adopted by the same group for area, micropores, uniform mesopores and macroporosity, carbon replicas [11,12]. The resulting carbons, named which facilitate its usage in adsorption, separation and MCF-carbon and C-nano-MSU-F, respectively, featured purification etc. uniform mesocells interconnected through uniform winThe silica monolith was synthesized by means of phase dows. The pore connectivity facilitated the diffusion of large molecules within these materials, thereby rendering them more effective for applications. Hyeon et al. [13] also reported the fabrication of carbons with bimodal pores, designated as Meso-nano-C, using a corresponding silica template. The structure of the Meso-nano-C was comparable with those of MCF-carbon and C-nano-MSU-F. Therefore, it could provide similar effectiveness. Though various structured mesoporous carbons have been synthesized, most of them are in the form of powder. For the development of their actual applications, it is