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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.

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.

Huang Y.,Shanxi Xinhua Chemical Co. | Jin Y.,Shanxi Xinhua Chemical Co. | Huang Z.,Shanxi Xinhua Chemical Co.
Lizi Jiaohuan Yu Xifu/Ion Exchange and Adsorption | Year: 2012

This paper summarized different methods that used to calculate mesopore distribution. We calculated the pore size distribution of DP activated carbon through equivalent cylinder model deduced by Jimin Yan and Qiyuan Zhang, BJH method, model-free method, and Dubinin equation. The differences were compared as well.

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.

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.

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.

Gong X.-J.,Harbin Institute of Technology | Li W.-G.,Harbin Institute of Technology | Wang G.-Z.,Harbin Institute of Technology | Zhang D.-Y.,Harbin Institute of Technology | And 2 more authors.
Environmental Science and Pollution Research | Year: 2015

The preparation, characterization, and performance evaluation of an innovative mesoporous activated carbon (C-XHIT) were conducted in this study. Comparative evaluation with commercial carbons (C-PS and C-ZJ15) and long-term performance evaluation of C-XHIT were conducted in small-scale system-A (S-A) and pilot-scale system-B (S-B-1 and S-B-2 in series), respectively, for treating water from Songhua River. The cumulative uptake of micropollutants varied with KBV (water volume fed to columns divided by the mass of carbons, m3 H2O/kg carbon) was employed in the performance evaluation. The results identified that mesoporous and microporous volumes were simultaneously well-developed in C-XHIT. Higher mesoporosity (63.94 %) and average pore width (37.91 Å) of C-XHIT ensured a higher adsorption capacity for humic acid compared to C-PS and C-ZJ15. When the KBV of S-A reached 12.58 m3 H2O/kg carbon, cumulative uptake of organic pollutants achieved by C-XHIT increased by 32.82 and 156.29 % for DOC (QC) and 22.53 and 112.48 % for UV254 (QUV) compared to C-PS and C-ZJ15, respectively; in contrast, the adsorption capacity of NH4 +-N did not improve significantly. C-XHIT achieved high average removal efficiencies for DOC (77.43 ± 16.54 %) and UV254 (83.18 ± 13.88 %) in S-B over 253 days of operation (KBV = 62 m3 H2O/kg carbon). Adsorption dominated the removal of DOC and UV254 in the initial phases of KBV (0–15 m3 H2O/kg carbon), and simultaneous biodegradation and adsorption were identified as the mechanisms for organic pollutant uptake at KBV above 25 m3 H2O/kg carbon. The average rates contributed by S-B-1 and S-B-2 for QC and QUV were approximately 0.75 and 0.25, respectively. Good linear and exponential correlations were observed between S-A and S-B in terms of QC and QUV obtained by C-XHIT, respectively, for the same KBV ranges, indicating a rapid and cost-saving evaluation method. The linear correlation between mesoporosity and QC (QUV) was also identified by the evolution of the property indices of C-XHIT. © 2015, Springer-Verlag Berlin Heidelberg.

Li B.,Southwest University of Science and Technology | Li B.,Xidian University | Chen A.-S.,Shanxi Xinhua Chemical Ltd Company | Liu H.-X.,Xidian University | And 3 more authors.
Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | Year: 2013

A novel device called double step buried oxide (BOX) SGOI n-type metal-oxide-semiconductor field-effect transistor (nMOSFET) was presented in order to eliminate the self-heating and short channel effect of strained Si grown on relaxed SiGe-on-insulator (SGOI). In this structure, a double step buried oxide was constructed below the channel region for minishing self-heating effect. Meanwhile, a ground plane (GP) was introduced below channel buried layer for reducing drain induced barrier lowering (DIBL) effect. A low field mobility model for strained Si device was established and implemented in the device simulator Sentaurus Device. In different cases of channel strain, both self-heating effect as a function of buried oxide thickness and short channel effect as a function of gate length were analyzed. Numerical simulation results indicate that output current of the device with Ge content of 0.4 increases by more than 50 percent compared with that of the device without Ge content. As buried oxide thickness below the channel region ranges from 100 to 10 nm, the self-heating temperature decreases by over 60°C. DIBL effect decreases by more than 25 percent and leakage current is greatly suppressed when a ground plane is involved.

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