title: Tailoring porosity in carbon spheres for fast carbon dioxide adsorption.
abstract: Highly-porous carbon spheres were prepared by modified Stöber method combined with silica templating and CO2activation. Silica was delivered in the form of either colloids or tetraethyl orthosilicate and used to create porosity. Subsequently, CO2activation was used to develop microporosity. CO2activation was done either: (1) on carbon spheres, following silica etching or (2) on silica-carbon composites, before silica removal. Both methods delivered carbon materials with well-developed structures and, importantly, preserved spherical morphology. Still, activation of the silica-carbon composites with subsequent silica etching afforded carbons with better structural properties and CO2adsorption. Between materials prepared with silica colloids and TEOS-generated silica, the former showed more developed structures. The best material had specific surface area reaching 1500 m2g-1and total pore volume exceeding 1.2 cm3g-1and showed CO2uptakes as high as 7.8 mmol g-1(0 °C, 1 bar) and 4.0 mmol g-1(23 °C, 1 bar). Mesoporosity improved mass transfer, which directly translated to faster CO2equilibration (30-40% on average). The proposed synthesis afforded carbons with high and fast CO2adsorption, which makes them good candidates for CO2sorption applications. Moreover, it was shown that both, microporosity and mesoporosity, are important in development of prospective CO2sorbents.
authors: Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.
authors: Jowita
authors: J
authors: Marszewska
authors: Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA. Electronic address: jaroniec@kent.edu.
authors: Mietek
authors: M
authors: Jaroniec
keywords: CO(2) adsorption; Carbon spheres; Mesoporosity; Microporosity; Nitrogen adsorption