Hierarchical Porous Materials: Capillaries in Nanoporous Carbon

Abstract

A hierarchical carbon material containing nanopores (micropores and mesopores) and micrometric sized capillaries (macropores) is produced using a combination of hard and soft templates. The hard template is a polypropylene (PP) cloth which decomposes during pyrolysis leaving a macroporous structure. The soft template is a cationic polyelectrolyte which stabilizes the resorcinol/formaldehyde (RF) resin porous structure during drying to give a nanoporous RF resin. The method produces a nanocomposite of the porous RF resin with an imbibed PP cloth. The composite is then pyrolyzed in a inert gas atmosphere to render a carbon material having macropores as well as micro/mesopores. The material exhibits both a large surface area ( S BET = 742 ± 2 m 2/ g ) due to nanopores and goof fluid permeability due to micrometric sized pores. The macropores can be oriented during fabrication. The nanoporous surface can be used to support metal nanoparticles for fuel cell while the macropores allow easy flux of gas and liquids through the monolithic material.

Nanostructured mesoporous carbons: Tuning texture and surface chemistry

“…In terms of industrial scalability, evaporative drying without any preliminary treatment is obviously the most attractive drying procedure due to its simplicity and low-cost. It was recently discovered that the use of cationic surfactants during synthesis stabilizes the pore structure during solvent [32][33][34]. Hence, surfactants adsorb on the hydrogel reducing the interfacial tension and preventing collapse of the pores during water removal.…”

Cobalt and Iron Complexes with N-heterocyclic Ligands as Pyrolysis Precursors for Oxygen Reduction Catalysts

“…The surface area (BET) of this material is 470 m 2 g À1 . The preparation and characterization has already been described in a previous report from our group [32]. The carbon material in a powder form was grinded and passed through a 40 mm pore sieve.…”

Carbon Materials for Fuel Cells

“…Without water transport channels (WTC) the O 2 path through the GDL to the catalyst might be The aforementioned results were very promising in order to improve the fuel cell performance. Working in a similar idea, Bruno et al [81,121] presented a novel method to produce mesoporous carbon monolith, obtained by a soft template method, with channels in the through plane direction of the materials using polypropylene fibers as a hard template. This simple method produces channels, 15 μm in diameter, together with meso and micropores in a single carbonization step of the resorcinol-formaldehyde resin used as precursor.…”