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Abnormal magnetic behavior of prussian blue analogs modified with multi-walled carbon nanotubes
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作者 莫家俊 夏溥越 +6 位作者 沈纪宇 陈海文 陆泽一 徐诗语 张庆航 夏艳芳 刘敏 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期639-645,共7页
This work examines the origin of the abnormal magnetism exhibited by Cu Mn Fe-PBAs modified with multi-walled carbon nanotubes(MWCNTs).The system of Cu Mn Fe-PBAs@MWCNTs coexists with both large and small clusters.Cu ... This work examines the origin of the abnormal magnetism exhibited by Cu Mn Fe-PBAs modified with multi-walled carbon nanotubes(MWCNTs).The system of Cu Mn Fe-PBAs@MWCNTs coexists with both large and small clusters.Cu Mn Fe-PBAs clusters have an average particle size of 28 nm,and some of the smaller particles are adsorbed on the surface of MWCNTs.Surprisingly,the magnitude of magnetization increases linearly with decreasing temperature.When above the Curie temperature,the magnitude of magnetization is significantly greater than that of PBAs without being modified.This phenomenon can be attributed to magnetostatic interactions between ultra-fine magnetic nanoparticles adsorbed on the surface of MWCNTs.Using the Monte Carlo method,we simulated the magnetostatic interaction of cylindrical adsorbed particles,and the simulation results are almost identical to those observed experimentally.The results indicate that 0.089Cu Mn Fe-PBAs clusters per 1 nm^(2)can be adsorbed onto the surface area of MWCNTs.We demonstrate that MWCNTs adsorbing magnetic particles exhibit magnetic behavior,and suggest a method for producing ultrafine materials.It also introduces a new method of calculating the adsorption efficiency of carbon nanotubes,offering theoretical guidance for future research on nanomaterials with enhanced adsorption efficiency. 展开更多
关键词 multi-walled carbon nanotubes prussian blue analogue Monte Carlo simulation magnetostatic interaction
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Enhanced thermal and electrical properties of poly (D,L-lactide)/ multi-walled carbon nanotubes composites by in-situ polymerization 被引量:5
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作者 李清华 周勤华 +4 位作者 邓丹 俞巧珍 谷俐 龚科达 徐科航 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第5期1421-1427,共7页
Biodegradable poly (D,L-lactide) (PLA)/carboxyl-functionalized multi-walled carbon nanotubes (c-MWCNTs) composites were achieved via in-situ polymerization. These as-prepared composite materials were characteriz... Biodegradable poly (D,L-lactide) (PLA)/carboxyl-functionalized multi-walled carbon nanotubes (c-MWCNTs) composites were achieved via in-situ polymerization. These as-prepared composite materials were characterized with FT-IR, XRD, TG, DSC, SEM, and high insulation resistance meter. The results demonstrate that the multi-walled carbon nanotube was carboxyl functionalized, which improved the collection between c-MWCNTs and PLA, and further realized the graft copolymerization of c-MWCNTs and PLA. There is a higher glass transition temperature and a lower pyrolysis temperature of PLA/c-MWCNTs composites than pure PLA. The c-MWCNTs gave a better dispersion than unmodified MWCNTs in the PLA matrix, and an even coating of PLA on the surface of c-MWCNTs was obtained, which increased the interfacial interaction. High insulation resistance analysis showed that the addition of c-MWCNTs increased the electric conductivity, and c-MWCNTs performed against the large dielectric coefficient and electrostatic state of PLA. These results demonstrated that c-MWCNTs modified PLA composites were beneficial for potential application in the development of heat-resisting and conductivity plastic engineering. 展开更多
关键词 in-situ polymerization multi-walled carbon nanotubes POLYLACTIDE thermal properties electrical conductivity
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Effect of electron beam irradiation on multi-walled carbon nanotubes 被引量:2
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作者 李斌 凤仪 +3 位作者 丁克望 钱刚 张学斌 刘衍芳 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第3期764-769,共6页
Multi-walled carbon nanotubes (MWCNTs) were irradiated with focused electron beams in a transmission electron microscope at room temperature. The results showed that carbon nanotubes had no obvious structural damage... Multi-walled carbon nanotubes (MWCNTs) were irradiated with focused electron beams in a transmission electron microscope at room temperature. The results showed that carbon nanotubes had no obvious structural damages but only shell bending under 100 keV electron beam irradiation. However, when the electron energy increased to 200 keV, the nanotubes were damaged and amorphization, pits and gaps were detected. Furthermore, generating of carbon onions and welding between two MWCNTs occurred under 200 keV electron irradiation. It was easy to destroy the MWCNTs as the electron beams exceeded the displacement threshold energy that was calculated to be 83-110 keV. Conversely, the energy of electron beams below the threshold energy was not able to damage the tubes. The damage mechanism is sputtering and atom displacement. 展开更多
关键词 multi-walled carbon nanotube (MWCCNTs) electron bean irradiation MORPHOLOGY damage mechanism
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Toxicity of Multi-Walled Carbon Nanotubes,Graphene Oxide,and Reduced Graphene Oxide to Zebrafish Embryos 被引量:6
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作者 LIU Xiao Tong MU Xi Yan +6 位作者 WU Xiao Li MENG Li Xuan GUAN Wen Bi MA Yong Qiang SUN Hua WANG Cheng Ju LI Xue Feng 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2014年第9期676-683,共8页
Objective This study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), and reduced graphene oxide (RGO), on zebrafish embryos. Metho... Objective This study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), and reduced graphene oxide (RGO), on zebrafish embryos. Methods The 2-h post-fertilization (hpf) zebrafish embryos were exposed to MWCNTs, GO, and RGO at different concentrations (1, 5, 10, 50, 100 mg/L) for 96 h. Afterwards, the effects of the 3 nanomateria on spontaneous movement, heart rate, hatching rate, length of larvae, mortality, and malformations Is were evaluated. Results Statistical analysis indicated that RGO significantly inhibited the hatching of zebrafish embryos. Furthermore, RGO and MWCNTs decreased the length of the hatched larvae at 96 hpf. No obvious morphological malformation or mortality was observed in the zebrafish embryos after exposure to the three nanomaterials. Conclusion MWCNTs, GO, and RGO were all toxic to zebrafish embryos to influence embryos hatching and larvae length. Although no obvious morphological malformation and mortality were observed in exposed zebrafish embryos, further studies on the toxicity of the three nanomaterials are still needed. 展开更多
关键词 Zebrafish Embryos TOXICITY multi-walled carbon Nanotubes Graphene Oxide Reduced Graphene Oxide
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In situ synthesis of palladium nanoparticles on multi-walled carbon nanotubes and their electroactivity for ethanol oxidation 被引量:4
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作者 Qing-Feng Yi Li-Zhi Sun 《Rare Metals》 SCIE EI CAS CSCD 2013年第6期586-591,共6页
Pd nanoparticles(Pd-NPs)were prepared and directly anchored on the surface of multi-walled carbon nanotubes(MWCNTs)in the absence of chemical reduction agent,where MWCNTs were used as both the chemical reduction agent... Pd nanoparticles(Pd-NPs)were prepared and directly anchored on the surface of multi-walled carbon nanotubes(MWCNTs)in the absence of chemical reduction agent,where MWCNTs were used as both the chemical reduction agent and the support substrate of Pd-NPs.Effect of various surfactants on the in situ deposition of PdNPs on MWCNTs was investigated.When MWCNTs were modified with a cationic surfactant(hexadecyl trimethyl ammonium bromide,CTAB),the amount of the Pd-NPs(Pd-NP/CTAB-MWCNT)generated by such an in situ deposition method gets a notable increase,and the size of the as-synthesized Pd-NPs becomes smaller,compared with those in the absence of any surfactant(Pd-NP/MWCNT)or in the presence of an anionic surfactant SDS(Pd-NP/SDS-MWCNT)and a neutral surfactant OP(PdNP/OP-MWCNT).Results show that the MWCNTs modified with CTAB are propitious to the in situ reduction of Pd2?.Among the prepared catalysts,Pd-NP/CTABMWCNT displays the highest electroactivity for ethanol oxidation in alkaline media. 展开更多
关键词 Pd nanoparticle multi-walled carbon nanotube Ethanol oxidation SURFACTANT
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Ultrasensitive electrochemical determination of metronidazole based on polydopamine/carboxylic multi-walled carbon nanotubes nanocomposites modified GCE 被引量:3
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作者 Satar Tursynbolat Yrysgul Bakytkarim +1 位作者 Jianzhi Huang Lishi Wang 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2018年第2期124-130,共7页
An ultrasensitive electrochemical sensor based on polydopamine/carboxylic multi-walled carbon nanotubes(MWCNTs à COOH) nanocomposites modified glassy carbon electrode(GCE) was presented in this work, which has be... An ultrasensitive electrochemical sensor based on polydopamine/carboxylic multi-walled carbon nanotubes(MWCNTs à COOH) nanocomposites modified glassy carbon electrode(GCE) was presented in this work, which has been developed for highly selective and highly sensitive determination of an antimicrobial drug, metronidazole. The preparation of polydopamine/MWCNTs–COOH nanocomposites/GCE sensor is simple and possesses high reproducible, where polydopamine can be coated on the surface of MWCNTs–COOH via a simple electropolymerization process. Under optimized conditions, the proposed sensor showed ultrasensitive determination for metronidazole with a wide linear detection range from5 to 5000 mmol/dm^3 and a low detection limit of 0.25 mmol/dm^3(S/N=3). Moreover, the proposed sensor has been successfully applied for the quantitative determination of metronidazole in real drug samples. This work may provide a novel and effective analytical platform for determination of metronidazole in application of real pharmaceutical and biological samples analysis. 展开更多
关键词 METRONIDAZOLE POLYDOPAMINE Carboxylic multi-walled carbon NANOTUBES NANOCOMPOSITES ELECTROCHEMICAL determination ELECTROCHEMICAL sensor
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Preparation of multi-walled carbon nanotube–Fe composites and their application as light weight and broadband electromagnetic wave absorbers 被引量:3
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作者 刘渊 刘祥萱 王煊军 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第11期552-555,共4页
Multi-walled carbon nanotube (MWCNT)-Fe composites were prepared via the metal organic chemical vapor deposi- tion by depositing iron pentacarbonyl on the surface of MWCNTs. The structural and morphological analyses... Multi-walled carbon nanotube (MWCNT)-Fe composites were prepared via the metal organic chemical vapor deposi- tion by depositing iron pentacarbonyl on the surface of MWCNTs. The structural and morphological analyses demonstrated that Fe nanoparticles were deposited on the surface of the MWCNTs. The electromagnetic properties of the MWCNTs were significantly changed, and the absorbing capacity evidently improved after the Fe deposition on the MWCNT surface. A minimum reflection loss of -29.4 dB was observed at 8.39 GHz, and the less than -10 dB bandwidth was about 10.6 GHz, which covered the whole X band (8.2-12.4 GHz) and the whole Ku band (12.4-18 GHz), indicating that the MWCNT-Fe composites could be used as an effective microwave absorption material. 展开更多
关键词 multi-walled carbon nanotube nano composites electrical properties microwave absorber
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Production of High Purity Multi-Walled Carbon Nanotubes from Catalytic Decomposition of Methane 被引量:3
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作者 Kong Bee Hong Aidawati Azlin Binti Ismail +2 位作者 Mohamed Ezzaham Bin Mohd Mahayuddin Abdul Rahman Mohamed Sharif Hussein Sharif Zein 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2006年第4期266-270,共5页
Acid-based purification process of multi-walled carbon nanotubes (MWNTs) produced via catalytic decomposition of methane with NiO/TiO2 as a catalyst is described. By combining the oxidation in air and the acid reflu... Acid-based purification process of multi-walled carbon nanotubes (MWNTs) produced via catalytic decomposition of methane with NiO/TiO2 as a catalyst is described. By combining the oxidation in air and the acid refluxes, the impurities, such as amorphous carbon, carbon nanoparticles, and the NiO/TiO2 catalyst, are eliminated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images confirm the removal of the impurities. The percentage of the carbon nanotubes purity was analyzed using thermal gravimetric analysis (TGA). Using this process, 99.9 wt% purity of MWNTs was obtained. 展开更多
关键词 multi-walled carbon nanotubes PURIFICATION acid refluxes OXIDATION METHANE DECOMPOSITION
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Adsorption and desorption phenomena on thermally annealed multi-walled carbon nanotubes by XANES study 被引量:2
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作者 Camile Rodolphe Tchenguem Kamto Bridinette Thiodjio Sendja Jeannot Mane Mane 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第9期145-149,共5页
The multi-walled carbon nanotubes(MWCNTs) studied in this work were synthesized by the catalytic chemical vapor deposition(CCVD) process, and were thermally annealed by the hot filament plasma enhanced(HF PE) method a... The multi-walled carbon nanotubes(MWCNTs) studied in this work were synthesized by the catalytic chemical vapor deposition(CCVD) process, and were thermally annealed by the hot filament plasma enhanced(HF PE) method at 550℃ for two hours.The x-ray absorption near edge structure(XANES) technique was used to investigate the adsorption and desorption phenomena of the MWCNTs at normal and grazing incidence angles.The adsorbates were found to have different sensitivities to the thermal annealing.The geometry of the incident beam consistently gave information about the adsorption and desorption phenomena.In addition, the adsorption of non-intrinsic potassium quantitatively affected the intrinsic adsorbates and contributed to increase the conductivity of the MWCNTs.The desorption of potassium was almost 70% greater after the thermal annealing.The potassium non-intrinsic adsorbates are from a physisorption mechanism whereas the intrinsic adsorbates result from chemisorption. 展开更多
关键词 multi-walled carbon NANOTUBES thermal ANNEALING adsorption DESORPTION
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Crystallization Behavior and Mechanical Properties of Poly(vinylidene fluoride)/multi-walled Carbon Nanotube Nanocomposites 被引量:3
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作者 XU Yue ZHENG Wei-tao +3 位作者 YU Wen-xue HUA Li-gui ZHANG Yu-jie ZHAO Zhu-di 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2010年第3期491-495,共5页
Poly(vinylidene fluoride)(PVDF)/multi-walled carbon nanotube(MWCNT) nanocomposites were prepared by means of ultrasonic dispersion method. X-ray diffraction(XRD) results indicate that incorporating MWCNTs into... Poly(vinylidene fluoride)(PVDF)/multi-walled carbon nanotube(MWCNT) nanocomposites were prepared by means of ultrasonic dispersion method. X-ray diffraction(XRD) results indicate that incorporating MWCNTs into PVDF caused the formation of β phase. A thermal annealing at 130 ℃ confirmed that the β phase was stable in the nanocomposites. Differential scanning calorimetry(DSC) results indicate that the melting temperature slightly increased while the heat of fusion markedly decreased with increasing MWCNT content. The tensile strength and modulus of PVDF were improved by loading the MWCNTs. The scanning electron microscopy(SEM) observations showed that MWCNTs were uniformly dispersed in the PVDF matrix and an interfacial adhesion between MWCNT and PVDF was achieved, which was responsible for the enhancement in the tensile strength and modulus of PVDE. 展开更多
关键词 multi-walled carbon nanotube Poly(vinylidene fluoride) COMPOSITE Crystalline structure Mechanical property
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Enhanced electrocatalytic activity for H_2O_2 production by the oxygen reduction reaction: Rational control of the structure and composition of multi-walled carbon nanotubes 被引量:3
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作者 Yi Wang Mi Yi +1 位作者 Kun Wang Shuqin Song 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第4期523-533,M0003,共12页
Hydrogen peroxide(H2O2)is a very useful chemical reagent,but the current industrial methods for its production suffer from serious energy consumption problems.Using high-activity and high-selectivity catalysts to elec... Hydrogen peroxide(H2O2)is a very useful chemical reagent,but the current industrial methods for its production suffer from serious energy consumption problems.Using high-activity and high-selectivity catalysts to electrocatalyze the oxygen reduction reaction(ORR)through a two-electron(2e^-)pathway is a very promising route to produce H2O2.In this work,we obtained partially oxidized multi-walled carbon nanotubes(MWCNTs)with controlled structure and composition by oxidation with concentrated sulfate and potassium permanganate at 40℃ for 1 h(O-CNTs-40-1).The outer layers of O-CNTs-40-1 are damaged with defects and oxygen-containing functional groups,while the inner layers are maintained intact.The optimized structure and composition of the partially oxidized MWCNTs ensure that O-CNTs-40-1 possesses both a sufficient number of catalytic sites and good conductivity.The results of rotating ring disk electrode measurements reveal that,among all oxidized MWCNTs,O-CNTs-40-1 shows the greatest improvement in hydrogen peroxide selectivity(from ~ 30% to ~ 50%)and electron transfer number(from ~ 3.4 to ~ 3.0)compared to those of the raw MWCNTs.The results of electrochemical impedance spectroscopy measurements indicate that both the charge-transfer and intrinsic resistances of O-CNTs-40-1 are lower than those of the raw MWCNTs and of the other oxidized MWCNTs.Finally,direct tests of the H2O2 production confirm the greatly improved catalytic activity of O-CNTs-40-1 relative to that of the raw MWCNTs. 展开更多
关键词 Hydrogen peroxide Oxygen reduction reaction multi-walled carbon nanotubes Electrocatalytic activity Oxidation treatment
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FLEXURAL WAVE DISPERSION IN MULTI-WALLED CARBON NANOTUBES CONVEYING FLUIDS 被引量:3
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作者 Lifeng Wang Wanlin Guo Haiyan Hu 《Acta Mechanica Solida Sinica》 SCIE EI 2009年第6期623-629,共7页
Motivated by the great potential of carbon nanotubes for developing nanofluidic devices, this paper presents a nonlocal elastic, Timoshenko multi-beam model with the second order of strain gradient taken into consider... Motivated by the great potential of carbon nanotubes for developing nanofluidic devices, this paper presents a nonlocal elastic, Timoshenko multi-beam model with the second order of strain gradient taken into consideration and derives the corresponding dispersion relation of flexural wave in multi-walled carbon nanotubes conveying fuids. The study shows that the moving flow reduces the phase velocity of flexural wave of the lowest branch in carbon nanotubes. The phase velocity of flexural wave of the lowest branch decreases with an increase of flow velocity. However, the effects of flow velocity on the other branches of the wave dispersion are not obvious. The effect of microstructure characterized by nonlocal elasticity on the dispersion of flexural wave becomes more and more remarkable with an increase in wave number. 展开更多
关键词 multi-walled carbon nanotube wave dispersion nonlocal elastic Timoshenko beam
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Adsorption of Cr(Ⅵ) in wastewater using magnetic multi-wall carbon nanotubes 被引量:2
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作者 Zhuo-nan Huang Xiao-ling Wang De-suo Yang 《Water Science and Engineering》 EI CAS CSCD 2015年第3期226-232,共7页
Magnetic multi-wall carbon nanotubes were prepared with wet chemical treatments and characterized by a transmission electron microscope (TEM) and X-ray diffraction (XRD). They were used as adsorbents for the remov... Magnetic multi-wall carbon nanotubes were prepared with wet chemical treatments and characterized by a transmission electron microscope (TEM) and X-ray diffraction (XRD). They were used as adsorbents for the removal of Cr(VI) in aqueous solutions. The effects of adsorbent dosage, the concentration of Cr(VI) in aqueous solution, temperature, and pH value on the removal efficiency were studied. Results showed that the adsorption capacity of the magnetic multi-wall carbon nanotubes increased with the initial Cr(VI) concentration, but decreased with the increase of adsorbent dosage. The adsorption amount increased with contact time. The adsorption kinetics were best represented by the pseudo second-order kinetic model, and the adsorption isotherms indicated that the Langmuir model better reflected the adsorption process. The ob- tained calculation results for the Gibbs free energy revealed that the adsorption was a spontaneous and endothermic process. The enthalpy deviation was 3.835 kJ.mol 1. The magnetic multi-wall carbon nanotubes showed significant potential for application in adsorption of heavy metal ions. 展开更多
关键词 Magnetic multi-wall carbon nanotubes Cr(VI) ADSORPTION KINETICS THERMODYNAMICS
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Polyaniline and multi-walled carbon nanotube composite electrode for rechargeable battery 被引量:2
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作者 Yu-Jeong LIM Min-Young PARK +2 位作者 Sang-Keol LEE Won-Ki LEE Nam-Ju JO 《中国有色金属学会会刊:英文版》 CSCD 2012年第S3期717-721,共5页
The multi-walled carbon nanotube was introduced into the polymer matrix (PANI) to improve the electric conductivity as well as mechanical properties of the original polymer matrix.PANI/multi-walled carbon nanotube (MW... The multi-walled carbon nanotube was introduced into the polymer matrix (PANI) to improve the electric conductivity as well as mechanical properties of the original polymer matrix.PANI/multi-walled carbon nanotube (MWCNT) composites were synthesized via ex-situ and in-situ polymerization to improve their electrical property.And the DC conductivities of PANI/MWCNT according to content and diameter of MWCNT were measured by four-point probe.The highest electric conductivity of PANI/MWCNT composite is 20 S/cm when 0.3% (mass fraction) MWCNTs with 10 nm in diameter and 15 μm in length are added in composite. 展开更多
关键词 POLYMER ELECTRODE electric CONDUCTIVITY multi-walled carbon NANOTUBE CONDUCTING POLYMER
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Synthesis and evaluation of carbon nanotubes composite adsorbent for CO2 capture: a comparative study of CO2 adsorption capacity of single-walled and multi-walled carbon nanotubes 被引量:2
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作者 Keren Osier Dhruti Dheda +2 位作者 Jacob Ngoy Nicola Wagner Michael O. Daramola 《International Journal of Coal Science & Technology》 EI 2017年第1期41-49,共9页
As a preliminary investigation towards obtaining carbon nanotube composite adsorbent for CO2 capture, in this study CO2 adsorption performance of three commercial carbon nanotubes (CNTs) one single-walled carbon nan... As a preliminary investigation towards obtaining carbon nanotube composite adsorbent for CO2 capture, in this study CO2 adsorption performance of three commercial carbon nanotubes (CNTs) one single-walled carbon nanotubes (SWCNTs), and two (2) different multi-walled carbon nanotubes (referred to as A-MWCNTs and B-MWCNTs) were evaluated and compared. The purpose of this study was to compare the different types of CNTs and select the best to serve as the solid anchor in the development of a hydrophobic composite adsorbent material for CO2 capture. The N2 physi- sorption of the CNTs was conducted to determine their surface area, pore volume and pore size. In addition, morphology and purity of the CNTs were checked with Transmission Electron Microscopy and Raman Spectroscopy, respectively. The CO2 adsorption capacity of the CNTs was evaluated using Thermo-gravimetric analysis (TGA) at 1.1 bar, at operating temperature ranged from 25 to 55 ~C and at different CO2 feed flow rates, in order to evaluate the effects of these variables on the CO2 adsorption capacity. The results of CO2 adsorption with the TGA show that CO2 adsorption capacity for both SWCNTs and MWCNTs was the highest at 25 ~C. Changing the CO2 flowrates had no significant effect on the adsorption capacity of MWCNTs, but decreasing the CO2 flow rate resulted in the enhancement of the CO2 adsorption capacity of SWCNTs. Overall, it was found that the SWCNTs displayed the highest CO2 adsorption capacity (29.97 gCO2/kg ad- sorbent) when compared to the MWCNTs (12.09 gCO2/kg adsorbent), indicating a 150% increase in adsorption capacity over MWCNTs. 展开更多
关键词 CO2 Capture ADSORPTION carbon nanotubes Single-walled nanotubes multi-walled nanotubes
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Purified oxygenand nitrogen-modified multi-walled carbon nanotubes as metal-free catalysts for selective olefin hydrogenation 被引量:2
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作者 Peirong Chen Ly May Chew +3 位作者 Aleksander Kostka Kunpeng Xie Martin Muhler Wei Xia 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第2期312-320,共9页
Oxygen and nitrogen-functionalized carbon nanotubes (OCNTs and NCNTs) were applied as metal-free catalysts in selective olefin hydro- genation. A series of NCNTs was synthesized by NH3 post-treatment of OCNTs. Tempe... Oxygen and nitrogen-functionalized carbon nanotubes (OCNTs and NCNTs) were applied as metal-free catalysts in selective olefin hydro- genation. A series of NCNTs was synthesized by NH3 post-treatment of OCNTs. Temperature-programmed desorption, N2 physisorption, Raman spectroscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the surface properties of OCNTs and NCNTs, aiming at a detailed analysis of the type and amount of oxygen- and nitrogen-containing groups as well as surface defects. The gas-phase treatments applied for oxygen and nitrogen functionalization at elevated temperatures up to 600 ℃ led to the increase of surface defects, but did not cause structural damages in the bulk. NCNTs showed a clearly higher activity than the pristine CNTs and OCNTs in the hydrogenation of 1,5-cyclooctadiene, and also the selectivity to cyclooctene was higher. The favorable catalytic properties are ascribed to the nitrogen-containing surface functional groups as well as surface defects related to nitrogen species. In contrast, oxygen-containing surface groups and the surface defects caused by oxygen species did not show clear contribution to the hydrogenation catalysis. 展开更多
关键词 multi-walled carbon nanotubes nitrogen-containing functional groups oxygen-containing functional groups metal-free catalyst selectiveolefin hydrogenation
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Preconcentration of copper with multi-walled carbon nanotubes pretreated by potassium permanganate cartridge for solid phase extraction prior to flame atomic absorption spectrometry 被引量:2
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作者 Jun Ping Xiao Qing Xiang Zhou Hua Hua Bai 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第6期714-717,共4页
A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water s... A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water samples. Important parameters, such as the sample pH, the concentration and volume of eluent, sample flow rate and volume, and interference of coexisting ions, were investigated. The obtained results indicated that proposed method possessed an excellent analytical performance. The linear range, the detection limit, and precison (RSD) were 1–100 ng/mL (R(2) = 0.9993), 0.32 ng/mL and 2.88%, respectively. The results showed that copper could be adsorbed quantitatively on the pretreated MWCNTs with potassium permanganate, and proposed method was very useful in the monitoring of copper in the environment. 展开更多
关键词 multi-walled carbon nanotubes Solid phase extraction (SPE) Flame atomic absorption spectrometry
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Synthesis and Characterization of W-doped TiO_2 Supported by Hybrid Carbon Nanomaterials of Multi-walled Carbon Nanotubes and C_(60) Fullerene by a Hydrothermal Method 被引量:1
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作者 史晓亮 ZHU Zhiwei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第2期207-214,共8页
W-doped TiO2 supported by hybrid carbon nanomaterials of multi-walled carbon nanotubes and C60 fullerene was synthesized by a simple hydrothermal method. The material displayed high visible light photocatalytic activi... W-doped TiO2 supported by hybrid carbon nanomaterials of multi-walled carbon nanotubes and C60 fullerene was synthesized by a simple hydrothermal method. The material displayed high visible light photocatalytic activity. X-ray diffraction, field emission transmission electron microscopy, ultra violet/visible light absorption and photoluminescence spectroscopy were used to characterize the material as photoeatalyst. Photocatalytic activity on the degradation of Rhodamine B dye in an aqueous solution under ultraviolet light and visible light irradiation was also studied. The experimental results indicated that the photocatalytic activity of the material was much higher than that of pure TiO2 or Degussa P25 TiO2. 展开更多
关键词 W-doped Ti02 hybrid carbon nanomaterials multi-walled carbon nanotubes C60 fullerene photocatalytic activity
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Electrochemical Reduction of Oxygen on Multi-walled Carbon Nanotubes Electrode in Alkaline Solution 被引量:1
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作者 YouQunCHU ChunAnMA FengMingZHAO HuiHUANG 《Chinese Chemical Letters》 SCIE CAS CSCD 2004年第7期805-807,共3页
The multi-walled carbon nanotubes (MWNTs) electrode was constructed using poly-tetrafluoroethylene as binder, and the electrochemical reductive behavior of oxygen in alkaline solution was first examined on this electr... The multi-walled carbon nanotubes (MWNTs) electrode was constructed using poly-tetrafluoroethylene as binder, and the electrochemical reductive behavior of oxygen in alkaline solution was first examined on this electrode. Compared with other carbon materials, MWNTs show higher electrocatalytic activity, and the reversibility of O2 reduction reaction is greatly improved. The experiments reveal that the electrochemical reduction of O2 to HO2- is controlled by adsorption. The preliminary results illustrate the potential application of MWNTs in fuel cells. 展开更多
关键词 Electrochemical reduction OXYGEN multi-walled carbon nanotubes.
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Curvature and Zeeman effects on persistent currents in a multi-walled carbon nanotorus 被引量:1
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作者 徐宁 丁建文 +1 位作者 马明明 汤贤 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第1期403-408,共6页
Taking into account both the intrinsic curvature and Zeeman effects, persistent currents in a multi-walled carbon nanotorus are explored by using a supercell method, within the tight-binding formalism. It is shown tha... Taking into account both the intrinsic curvature and Zeeman effects, persistent currents in a multi-walled carbon nanotorus are explored by using a supercell method, within the tight-binding formalism. It is shown that in the absence of the Zeeman effect, the intrinsic curvature induces some dramatic changes in energy spectra and thus changes in the shape of the flux-dependent current. A paramagnetism diamagnetism transition is observed. With consideration of the Zeeman splitting energy, the period of persistent current is destroyed, and a diamagnetism-paramagnetism transition is obtained at high magnetic field. In addition, we further explore the effect of external electric field energy (Eef) on persistent current, indicating that it changes unmonotonously with Eef. 展开更多
关键词 multi-walled carbon nanotorus tight-binding model persistent current
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