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Zhang C.,Taiyuan University of Technology | Song W.,ShanXi XinHua Chemical Co. | Ma Q.,Taiyuan University of Technology | Xie L.,Shanxi Institute of Coal CAS Chemistry | And 2 more authors.
Energy and Fuels | Year: 2016

A novel biomass-based carbon material was successfully prepared from black locust by KOH chemical activation in combination with surface modification by heat treatment with ammonia solution for enhancing CO2 adsorption. The textural and surface characteristics of the prepared activated carbons were analyzed with N2 adsorption isotherms, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), elemental analysis, and X-ray photoelectron spectroscopy (XPS). The results show that the modified activated carbon possesses a high surface area of 2511 m2/g, a large micropore volume of 1.16 cm3/g, and a high nitrogen content of 7.21 wt %. The adsorption behavior of CO2 onto all activated carbon samples was experimentally evaluated by a volumetric method at three different adsorption temperatures of 0, 25, and 50 °C under atmospheric pressure (1 bar). High CO2 uptakes of 7.19 and 5.05 mmol/g at 0 and 25 °C were achieved for the sample AC-KOH-N due to its well-developed micropore structure and abundant basic nitrogen-containing functionalities. The thermodynamic parameters indicate that both physical adsorption and chemical adsorption mechanisms for CO2 adsorption coexist in the sample AC-KOH-N. The sample AC-KOH-N also shows a good selectivity for CO2/N2 and fast adsorption kinetics that be easily regenerated with superior cyclic stability after multiple cycles. These results suggest that the obtained biomass-based activated carbon is promising for CO2 capture. © 2016 American Chemical Society. Source

Zhang C.,Shanxi Institute of Coal CAS Chemistry | Zhang C.,University of Chinese Academy of Sciences | Xie L.,Shanxi Institute of Coal CAS Chemistry | Xie L.,University of Chinese Academy of Sciences | And 4 more authors.
Journal of Electroanalytical Chemistry | Year: 2013

A nano-wired Co3O4 was successfully synthesized by a hydrothermal method in combination with subsequent calcination process. An asymmetric supercapacitor based on the Co3O4 as the positive electrode and the activated carbon (AC) as the negative electrode with a 6 M KOH solution as electrolyte was assembled. The electrochemical performance of the asymmetric supercapacitor was investigated by means of cyclic voltammetry and galvanostatic charge-discharge tests. A specific capacitance of 81 F g-1 as well as specific energy density of 24.9 W h kg -1 was obtained for the asymmetric supercapacitor within the voltage range of 0-1.5 V. The supercapacitor also exhibited a good cycling performance and kept 90% of initial capacity after 5000 cycles. © 2013 Elsevier B.V. All rights reserved. Source

Xie L.,Shanxi Institute of Coal CAS Chemistry | Sun G.,Shanxi Institute of Coal CAS Chemistry | Su F.,Shanxi Institute of Coal CAS Chemistry | Guo X.,Shanxi Institute of Coal CAS Chemistry | And 8 more authors.
Journal of Materials Chemistry A | Year: 2016

With willow catkins as highly accessible carbon sources, hierarchical porous carbon microtubes (denoted as HPNCTs) have been successfully prepared by a facile carbonization and subsequent KOH activation process. The resulting materials not only inherited the natural tubular morphology of willow catkins, but also developed a hierarchical porous structure by activation, with nitrogen from the biomass being self-doped in the resulting carbon. A maximum specific surface area of 1775.7 m2 g-1 with a pore volume of 0.8516 cm3 g-1 was achieved for HPNCT-800. When evaluated as an electrode by a three-electrode system in 6 M KOH aqueous solution, the material exhibited a high gravimetric capacitance of 292 F g-1 at a current density of 1 A g-1, with a good rate capability of 83.5% retention at 10 A g-1. HPNCT-800 was further employed in a coin-type symmetric device with 1 M LiPF6 electrolyte, and exhibited a high energy density of 37.9 W h kg-1 at a power density of 700 W kg-1, with excellent cycling stability with 90.6% retention after 4000 cycles. By taking advantage of the unique structure of abundant biomass from nature, this work sheds light on the creation of advanced porous carbon materials towards energy storage applications. © The Royal Society of Chemistry. Source

Zhang C.,Shanxi Institute of Coal CAS Chemistry | Zhang C.,University of Chinese Academy of Sciences | Song W.,ShanXi XinHua Chemical Co. | Sun G.,Shanxi Institute of Coal CAS Chemistry | And 8 more authors.
Energy and Fuels | Year: 2013

Amino/nitro groups were introduced onto the surface of the activated carbon (AC) with nitration followed by reduction in order to improve its adsorption capacity toward CO2. These AC samples were characterized by N 2 adsorption/desorption, FTIR, and X-ray photoelectron spectroscopy (XPS). CO2 adsorption properties of the samples were investigated using a self-regulating high-pressure adsorption apparatus. Results showed that the contents of nitrogen on the treated samples' surface increased from 0% to 1.38 after modification. The maximum CO2 adsorption capacity of the modified samples can reach 19.07 mmol/g at 298 K and 36.0 bar. The adsorbed amounts of CO2 on all samples decreased with an increase in the adsorption temperature, but the extent of the decrease with the modified samples was less than that of the raw AC sample. CO2 adsorption capacities of the modified sample for five cyclic adsorption-desorption runs were found to be nearly identical. © 2013 American Chemical Society. Source

Zhang C.,Shanxi Institute of Coal CAS Chemistry | Zhang C.,University of Chinese Academy of Sciences | Song W.,ShanXi XinHua Chemical Co. | Sun G.,Shanxi Institute of Coal CAS Chemistry | And 6 more authors.
Industrial and Engineering Chemistry Research | Year: 2014

Activated carbon spheres (ACSs) with high surface area and different porous structure were prepared from the fundamental chemical materials, 3-methylphenol and formaldehyde, by suspension polymerization and steam activation. The effects of two organic additives, ethylene glycol and poly(ethylene glycol), to the textural structure and adsorptive dibenzothiophene (DBT) of ACSs were investigated. The pyrolysis behavior of the resin spheres (RSs) was characterized by thermal gravimetric analysis. The texture properties of the obtained ACSs were characterized by N2 adsorption-desorption and scanning electron microscope (SEM) techniques. The as-prepared ACSs reached a Brunauer-Emmet-Teller (BET) surface area value as high as 1501 m2/g and a total pore volume of 0.72 cm3/g. The BET surface areas and pore volumes increased after adding two organic additives. The adsorptive capacity of DBT for model oil had a good linear correlation with the volume of small micropores (0.6 -1.2 nm). © 2014 American Chemical Society. Source

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