title: Highly selective and stable carbon dioxide uptake in polyindole-derived microporous carbon materials.
abstract: Adsorption with solid sorbents is considered to be one of the most promising methods for the capture of carbon dioxide (CO₂) from power plant flue gases. In this study, microporous carbon materials used for CO₂ capture were synthesized by the chemical activation of polyindole nanofibers (PIF) at temperatures from 500 to 800 °C using KOH, which resulted in nitrogen (N)-doped carbon materials. The N-doped carbon materials were found to be microporous with an optimal adsorption pore size for CO₂ of 0.6 nm and a maximum (Brunauer-Emmett-Teller) BET surface area of 1185 m(2) g(-1). The PIF activated at 600 °C (PIF6) has a surface area of 527 m(2) g(-1) and a maximum CO₂ storage capacity of 3.2 mmol g(-1) at 25 °C and 1 bar. This high CO₂ uptake is attributed to its highly microporous character and optimum N content. Additionally, PIF6 material displays a high CO₂ uptake at low pressure (1.81 mmol g(-1) at 0.2 bar and 25 °C), which is the best low pressure CO₂ uptake reported for carbon-based materials. The adsorption capacity of this material remained remarkably stable even after 10 cycles. The isosteric heat of adsorption was calculated to be in the range of 42.7-24.1 kJ mol(-1). Besides the excellent CO₂ uptake and stability, PIF6 also exhibits high selectivity values for CO₂ over N₂, CH₄, and H₂ of 58.9, 12.3, and 101.1 at 25 °C, respectively, and these values are significantly higher than reported values.
authors.affiliation: Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Saleh
authors.forename: Jitendra N
authors.initials: JN
authors.lastname: Tiwari
authors.forename: K Christain
authors.initials: KC
authors.lastname: Kemp
authors.forename: Muhammad
authors.initials: M
authors.lastname: Yousuf
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Kim
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D006358:Hot Temperature; D007211:Indoles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D011108:Polymers / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D007211:Indoles; D011108:Polymers; D002245:Carbon Dioxide; D002244:Carbon