Electrochemical Properties of Supercapacitors Using Boron Nitrogen Double-Doped Carbon Nanotubes as Conductive Additive

Hao Hu,Xiaogang Sun,Wei Chen,Jie Wang,Xu Li,Yapan Huang,Chengcheng Wei,Guodong Liang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

Carbon nanotubes (CNTs) were doped by ammonium borate as the sources of nitrogen and boron. Under the protection of Ar gas, boron-nitrogen doped CNTs were prepared through nitriding and boronization at high temperature. It is a conductive additive. Then, the obtained CNTs were mixed with activated carbon (AC), SP, sodium dodecyl sulfate (SDS), and cellulose fiber to prepare electrodes. With all the materials, a symmetric electric double-layer supercapacitor (EDLC) was assembled. Next, the materials and electrodes were also characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The factors, chemical connections, and specific surface area of the CNTs were analyzed by X-ray energy spectrum analysis (EDS), X-ray photoelectron spectroscopy (XPS), as well as a specific surface area and porosimetry analyzer (BET). In addition, the electrochemical performances of electric double-layer capacitors were tested with the help of cyclic voltammetry, constant-current charging and discharging, and so on. From the results, we can make a conclusion, that is, both B and N atoms were added into the CNTs and formed bonds successfully with carbon atoms mutually. Besides, the specific surface area is about 1.5 times than that of the CNT. When the charge/discharge current density reaches 50 mA/g, we can find that the mass specific capacitance of the capacitor can run up to 32.19 F/g. Also, we observe that the maximum power density is close to 220 W/kg (700 mA/g), and the energy density can arrive 9.31 Wh/kg (50 mA/g). Based on the impedance test, the electrodes are characterized with low impedance. After 2000 cycles, the boron-nitrogen doped double-layer capacitors maintain a capacitance retention ratio of above 95%. Its power density can still achieve 220 W/kg when the energy density keeps at 3.46 Wh/kg. In other words, the electrochemical performance functions of the electric double-layer capacitors are enhanced while the CNTs serve as the electrodes.

Enhanced photocatalytic capacity of ZnS–ZnO–Sm2O3 composites for the removal of dyes and antibiotics in visible light region

Xiaogang Zheng,Fuyan Kang,Congying Huang,Sihao Lv,JinYang Zhang,Hao Peng 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.88 No.-

ZnS–ZnO–Sm2O3 (Zn–Sm–XY) composites were prepared via the high-temperature calcination of coreshellstructured ZnS@Sm2O3 for the enhanced photocatalytic degradation of dyes and antibiotics invisible light region. Effects of calcined temperature, Sm2O3 content, pH value, contaminantconcentration, and inorganic ions on the photocatalytic activity were investigated. Ternary Zn–Smcomposites exhibit the excellent photocatalytic activity for the visible light driven degradation oftetracycline hydrochloride. Among these composites, Zn–Sm–2B prepared via the heat-treatment ofZnS–Sm2O3 at 673 K shows the best photocatalytic activity for the removal of tetracycline hydrochloride. The enhanced photocatalytic activity of Zn–Sm–2B is also achieved for the visible light drivendegradation of methyl orange, methylene blue, and rhodamine B within 20 min. In addition, Zn–Sm–6Ccalcined from Zn–Sm–C at 1073 K as well as Zn–Sm–2B exhibits excellent photocatalytic activity. OH andO2radicals are vital for the enhanced photocatalytic activity of Zn–Sm–2B and Zn–Sm–2B in visiblelight region, respectively. The lattice defects, sulfur vacancies, and oxygen vacancies facilitate the efficientcharge transfer and the rapid separation of electron-hole pairs at the junction interface of Zn–Sm–2B.

Enhanced photo-Fenton degradation of tetracycline using TiO2-coated α-Fe2O3 core–shell heterojunction

Xiaogang Zheng,Wendi Fu,Fuyan Kang,Hao Peng,Jing Wen 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.68 No.-

TiO2-coated cubic α-Fe2O3 with mostly exposed (012) and (101) facets (α-Fe2O3@TiO2) was fabricated using a hydrothermal route for the photo-Fenton degradation of tetracycline under visible light irradiation. TiO2 coating could greatly affect the photocatalytic activity of α-Fe2O3@TiO2. Compared with cubic α-Fe2O3 alone for photodegradation of tetracycline, α-Fe2O3@TiO2 with TiO2 shell of around 15 nm exhibited higher removal efficiency of tetracycline in photo-Fenton system, and its durability was slightly affected after five cycle times under same conditions. It is ascribed to the well-matched interface between cubic α-Fe2O3 core and TiO2 shell, leading to the broadened light-absorption and the efficient separation of photo-generated electon–hole pairs. The OH radicals were main responsible for the advanced photocatalytic performance of α-Fe2O3@TiO2 in visible-light driven degradation of tetracycline.

Three-Dimensional Porous Carbon Nanotube Papers as Current Collector and Buffer for SnO2 Anodes

Xiaogang Sun,Zhiwen Qiu,Long Chen,Manyuan Cai,Jie Wang,Xu Li,Wei Chen,Zhenhong Liu,Hao Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.11

A novel three-dimensional porous conductive papers have been successfully synthesized via a simple physical route. Multi-walled carbon nanotubes (MWCNTs)@SnO2 composite anode materials are embedded in porous conductive papers. The peculiar structure can accommodate the huge volume expansion of MWCNTs@SnO2 composite anode materials during charge–discharge process. The framework formed by MWCNTs and cellulose can greatly improve the strength, stability and flexibility of the electrode. In addition, the structure successfully prevent the aggregation of SnO2 nanoparticles and collapse of MWCNTs@SnO2 composite electrode, leading to the improvement in electrochemical utilization and stable cyclability. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The electrochemical properties and application were evaluated by galvanostatic discharge–charge testing and cycling voltammetry. As a result, the MWCNTs@SnO2 composite electrode showed excellent rate performance. The discharge capacity remains about 680mAh g -1 after 100 cycles at 200mA g -1, and even around 300mAh g -1 at 1000mA g -1.

Carbon-coated Mg–Al layered double oxide nanosheets with enhanced removal of hexavalent chromium

Xiaogang Zheng,Fuyan Kang,Xinhui Liu,Hao Peng,JinYang Zhang 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

Carbon-coated Mg–Al layered double oxide (MgAl@C LDO) nanosheets were synthesized for the removalof hexavalent chromium (Cr(VI)) ions. Carbon coating could enhance the sorption capacity of Mg5Al1 LDOfor the Cr(VI) removal. The sorption capacity of Mg5Al1@C LDO increased and then decreased with anincrease in carbon-coated content, of which the Mg5Al1@C-2 with a carbon thickness of around 5.0 nmexhibited the best sorption capacity. The sorption behaviors of Mg5Al1@C-2 was explained by Langmuirsorption model, pseudo-second-order model, Weber–Morris model, and Boyd kinetic model. Mg5Al1@C-2 for Cr(VI) removal was a spontaneous, endothermic, and chemisorption process.

Efficient solar-light photocatalytic H2 evolution of Mn0.5Cd0.5S coupling with S,N-codoped carbon

Hao Peng,Congying Huang,Xiaogang Zheng,Jing Wen 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

The low-cost and highly-efficient photocatalysts for solar-light induced water splitting had drawn greatattention to develop the renewable hydrogen economy. To enhance the solar-light driven H2 evolution ofMn0.5Cd0.5S, Mn0.5Cd0.5S was modified by S,N-codoped carbon (3-MCS/SN-C) via the in-situ sulfurizationat high temperature. In contrast with Mn0.5Cd0.5S (11.13 mmol g1 h1) and S-doped g-C3N4(0.35 mmol g1 h1), the optimal 3-MCS/SN-C with a mass ratio of Mn0.5Cd0.5S to S,N-codoped carbonof 1:3 exhibited the best H2 evolution rate of 27.58 mmol g1 h1 and an apparent quantum yield of27.43% at 400 nm. The photo-corrosion induced to the decreased H2 evolution capacity of 3-MCS/SN-Cfrom 131.13 to 126.52 mmol g1 after five cycles of 5 h. S,N-codoped carbon could efficiently capture visiblelight and absorb the photons, leading to the efficient transformation and separation of photogeneratedcarriers at the junction interface between Mn0.5Cd0.5S and S,N-codoped carbon.

Carbon Nanotube Paper as Anode for Flexible Lithium-Ion Battery

Xiaogang Sun,Zhenhong Liu,Neng Li,Xiaoyong Wu,Yanyan Nie,Zhipeng Pang,Lifu Yue,Hao Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.11

In this investigation, multiwalled carbon nanotube (MWCNT) paper consists of MWCNTs and cellulose was fabricated by traditional paper-making method. It was applied directly as negative electrode in flexible lithium ion battery to replace ordinary electrode which is combined with anode material and current collector. The electrochemical performances of the as-produced MWCNT paper (AMP) and carbonized MWCNT paper (CMP) were evaluated in this study. The morphology and structure of the MWCNT papers were observed by scanning electron microscopy (SEM). The electrochemical performance of the battery was operated by cell test and electrochemical impedance spectroscopy (EIS) measurement. The charging and discharging results indicated that the CMP behaves with higher capacity than AMP. And the EIS analysis showed that a lower charge transfer resistance can be obtained in the CMP. The excellent electrochemical performance verifies the feasibility of MWCNT papers as a promising candidate for the anode in flexible lithium ion battery.

MgO nanosheets with N-doped carbon coating for the efficient visible-light photocatalysis

Xiaogang Zheng,Ke Wang,Zhiping Huang,Yong Liu,Jing Wen,Hao Peng 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-

MgO nanosheets with N-doped carbon coating (MgO@N-C) were fabricated for the enhancedphotocatalytic degradation of dyes (methylene blue, methyl violet, and Rhodamine B) and antibiotics(ciprofloxacin and tetracycline hydrochloride) in visible light region. The effects of N-doping content,reactant concentration, pH value, and inorganic ions on the photocatalytic performance in degradation ofmethylene blue were investigated in this work. Narrow band gap energy and heterojunction interfaceendowed the extended light-harvesting capacity to visible light region and the efficient charge transfer,leading to the excellent photocatalytic activity and durability of MgO@N-C-3 with N-doping content of 1.52%.

Superfast Preparation of SWNT Sponge by Flame Burning Method and Its Adsorptive, Elastic and Electrochemical Properties

Liang Lu,Hao Tong,Fengqiao Jin,Shihong Yue,Qing Meng,Xiaogang Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.7

A compressible single-walled carbon nanotube (SWNT) sponge was developed by a superfast flame burning method in less than 20 s by moving polyurethane (PU) sponge template coated with SWNTs through an ethanol flame. By adjusting the geometries of the templates, the arbitrary shapes of the SWNT sponges composed of a unique network structure could be prepared as required. The SWNT sponges possessing good hydrophobicity and outstanding organic solvent adsorption capacity could adsorb various organic solvents and oils with high adsorption rate and good adsorption–volatilization and adsorption–combustion recycling performance. The SWNT sponges present good elasticity and compression stability even after a compressive strain of 80% and the 1000th loading/unloading cycle due to the stable skeleton structures. The SWNT sponges as flexible electrodes could also achieve high-specific capacitance of 126.8 F g -1 at 1Ag -1 and 95% capacitance retention after 10 000 charge/discharge cycles. Owing to the availability of the flame, easy decomposition of the PU sponge and flame resistance of SWNTs, this facile flame burning method was demonstrated to be a practical approach to prepare the SWNT sponges on a large scale with controllable shape and density, moderate organic liquid adsorption capability, good elasticity and decent electromechanical properties.

Electrochemical Performance of Lithium-Ion Capacitors Using Pre-Lithiated Multiwalled Carbon Nanotubes as Anode

Manyuan Cai,Xiaogang Sun,Yanyan Nie,Wei Chen,Zhiwen Qiu,Long Chen,Zhenhong Liu,Hao Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.4

Pre-lithiated multiwalled carbon nanotube anode was prepared by internal short circuit approach (ISC) for 5 min, 30 min, 60 min and 120 min respectively. Lithium ion capacitors (LICs) were assembled by using pre-lithiated multiwalled carbon nanotubes as anodes and activated carbon (AC) as cathodes. The structure of multiwalled carbon nanotubes and electrodes were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performance of pre-lithiated multiwalled carbon nanotube electrodes and pristine carbon nanotube electrodes were tested by galvanostatic charge/discharge and electrochemical impedance. The results indicated that pre-lithiation carbon nanotubes greatly improved the charge/discharge performance of LICs. The energy density was four times than conventional electric double-layer capacitors (EDLCs) at the current density of 100 mA/g. The LICs achieved a specific capacitance of 59.3 F/g at the current density of 100 mA/g with 60 min pre-lithiatiation process. The maximum energy density and power density was 96Wh/kg and 4035W/kg, respectively. The energy density still remained about 89.0% after 1000 cycles. The LIC showed excellent supercapacitor performance.