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1.
一种节状纳米碳纤维的CVD生长 总被引:2,自引:0,他引:2
介绍了以发泡Ni为催化剂、用CVD法生长节状纳米碳纤维的工艺过程,讨论了工艺参数对生成样品的产率和形貌的影响,同时还探讨了该样品的生长机理。认为催化剂的不同晶面分别有利于烃类气体的吸附解离或碳的沉积,因此催化剂颗粒的原始形貌影响了不同开貌的碳纤维生长。 相似文献
2.
Mariane C. Schnitzler 《Journal of solid state chemistry》2009,182(10):2867-1833
Thin films of Fe2O3 were obtained on silica glass substrates through the thermal decomposition of ferrocene in air. These films were characterized by Raman spectroscopy and X-ray diffractometry (XRD), and subsequently used as catalyst on the growth of carbon nanotubes, using benzene or a benzene solution of [Fe3(CO)12] as precursor. A great amount of a black powder was obtained as product, identified as multi-walled carbon nanotubes by XRD, Raman spectroscopy and transmission electron microscopy. The carbon nanotubes formed through the pyrolysis of the [Fe3(CO)12] solution were identified as structurally better than the one obtained by the pyrolysis of pristine benzene. 相似文献
3.
An iron compound containing guanidinate ligand [Fe((SiMe3)2NC(iPrN)2)2] was synthesized using a conventional lithium‐salt‐elimination reaction, and its chemical structure was characterized through elemental analysis, 1H‐NMR and single‐crystal X‐ray diffraction, respectively. The thermal properties of the compound were examined through thermogravimetric analysis (TGA), and the TGA results demonstrated that the compound possessed sufficient volatility and suitable thermal stability for the CVD process. Moreover, the deposition experiments were conducted using the synthesized compound as a precursor and O2 as an oxygen source to confirm its applicability as a CVD precursor, and α‐Fe2O3 films were successfully deposited at a relatively low deposition temperature (300°C). 相似文献
4.
Mengci He Prof. Hongyan Shi Peng Wang Prof. Xiudong Sun Prof. Bo Gao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(70):16106-16113
Molybdenum carbide (Mo2C) is a promising noble-metal-free electrocatalyst for the hydrogen evolution reaction (HER), due to its structural and electronic merits, such as high conductivity, metallic band states and wide pH applicability. Here, a simple CVD process was developed for synthesis of a Mo2C on carbon cloth (Mo2C@CC) electrode with carbon cloth as carbon source and MoO3 as the Mo precursor. XRD, Raman, XPS and SEM results of Mo2C@CC with different amounts of MoO3 and growth temperatures suggested a two-step synthetic mechanism, and porous Mo2C nanostructures were obtained on carbon cloth with 50 mg MoO3 at 850 °C (Mo2C-850(50)). With the merits of unique porous nanostructures, a low overpotential of 72 mV at current density of 10 mA cm−2 and a small Tafel slope of 52.8 mV dec−1 was achieved for Mo2C-850(50) in 1.0 m KOH. The dual role of carbon cloth as electrode and carbon source resulted into intimate adhesion of Mo2C on carbon cloth, offering fast electron transfer at the interface. Cyclic voltammetry measurements for 5000 cycles revealed that Mo2C@CC had excellent electrochemical stability. This work provides a novel strategy for synthesizing Mo2C and other efficient carbide electrocatalysts for HER and other applications, such as supercapacitors and lithium-ion batteries. 相似文献
5.
D. Hanifeh Toubestani M. Ghoranneviss A. Mahmoodi M. Rahbar Zareh 《Macromolecular Symposia》2010,287(1):143-147
Summary: We report mass production of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) with relatively high length and aspect ratio. We synthesized carbon nanomaterials by chemical vapor deposition (CVD) of methane as the feeding gas on Fe/Mo nanoparticles that use alumina-aerogel support. Alumina-aerogel-supported Fe/Mo catalyst was prepared using sol-gel. Drying step performed using rotary evaporation and freeze-drying. CVD was performed using a quartz tube furnace. Samples were analyzed using scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Raman spectroscopy. 相似文献
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7.
Cigang Xu Emmanuel Flahaut Sam R. Bailey Gareth Brown Jeremy Sloan Karl S. Coleman V. Clifford Williams Malcolm L. H. Green * . Inorganic Chemistry Laboratory University of Oxford Oxford OX QR UK 《高等学校化学研究》2002,18(2):130-132
IntroductionSingle walledcarbonnanotubes(SWNTs)havebeensynthesisedbyusingvariousmethods[1— 3] andthechemicalvapourdeposition (CVD )methodhasbeenconsideredasa promisingmethodto produceSWNTsonanindustrialscale[3— 5] .However ,alltheSWNT productssynthesisedtodateco… 相似文献
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9.
催化剂载体对CVD法制备碳纳米管的影响 总被引:5,自引:0,他引:5
用DTA、TEM和XRD方法研究了碳氢化合物催化裂解制备碳纳米管(CNTs)反应中催化剂载体的影响。实验结果表明:当以金属Co作为活性组分时,对于催化剂Co/Al2O3,在最佳反应温度(650℃)条件下,碳纳米管粗产品的产率为457g/100g·cat,明显高于以Co/SiO2作载体时的产率131g/100g·cat,且碳纳米管直径小,直径分布范围窄(10nm~20nm)。但在空气气氛中的DTA结果表明,在催化剂Co/SiO2上生成的碳纳米管的抗氧化能力较在催化剂Co/Al2O3上生成的碳纳米管强。通过TEM和XRD方法进一步研究发现:反应过程中,催化剂Co/Al2O3中的Co微晶粒度随反应温度升高(从650℃到750℃)而增大(从15.8nm到16.7nm)的速率小于催化剂Co/SiO2中的Co微晶粒度随反应温度升高而增大(从11.0nm到13.4nm)的速率;相应地,在催化剂Co/Al2O3上生成的碳纳米管的(外)直径随反应温度升高而增大的速率(从10~20nm到20~25nm)亦小于在催化剂Co/SiO2上生成的碳纳米管的(外)直径随反应温度升高而增大的速率(从10~30nm到30~50nm)。 相似文献
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11.
K. Montasser J. Tamano S. Hattori S. Morita 《Plasma Chemistry and Plasma Processing》1984,4(4):251-260
A transparent boron-nitrogen thin film of thickness 550 nm was successfully deposited out of the discharge region by rf plasma CVD. The deposition was performed with diborane (4.8 vol % in N2) as the reactant gas and argon as the carrier gas by an inductively coupled reactor at a frequency of 13.56 MHz. The transparent films could be obtained at a low pressure of about 30 Pa, at a discharge power level of 30 W, and at room temperature without heating the substrate. The thin films obtained by rf plasma are compared with those obtained by microwave plasma. Both the refractive index and the deposition rate for the films deposited by microwave plasma are discussed according to the deposition conditions. 相似文献
12.
Multi-walled carbon nanotubes (MW-CNTs) were prepared by chemical vapor deposition (CVD) method with the decomposition of acetylene over Co/SiO2 catalyst. TG-DTA technique was used together with TEM and XRD to study the effect of reaction temperature on the composition, graphitized extent, and diameter distribution of the produced raw CNTs based on their oxidization resistance. During the decomposition, the micro-crystallite of the active constituent (Co/SiO2) were growing up as the reaction temperature rising. This in turn resulted in an increase of the diameter distribution range of produced MW-CNTs. The average diameter increased from 20~30 nm (650℃) to 30~50 nm (750℃). XRD results also showed the graphitized extent of MW-CNTs was enhanced meanwhile the spacing between the layers (d002) decreased from 3.45 (650℃) to 3.32 (850℃) with the reaction temperature raised. TG-DTA data showed that the exothermic peak of the amorphous carbon was below 380℃and its content would decrease as temperature increasing. In summary, for CVD production of CNTs using acetylene gas on Co/SiO2 catalyst, low temperature (about 650℃) favored producing thinner MW-CNTs with the diameter from 20 to 30 nm while higher temperature (about 850℃) is favored thicker MW-CNTs (diameter from 70 to 100 nm). 相似文献
13.
We could prepare highly electrically conducting graphitic carbon films and nano patterns by carbonizing the poly(p-phenylenevinylene) (PPV) films and nano patterns prepared on the silicon surface by the chemical vapor deposition polymerization method of α,α'-dichloro-p-xylene. When the PPV films on silicon wafers were thermally treated at 850°C highly oriented graphitic carbon films were obtained which exhibit an electrical conductivity higher than 0.7 x 103 Scm−1. This conductivity value is more than 10 times the value for the carbon films obtained from bulk PPV films or glassy carbons heat treated at the same temperature. Moreover, nano patterns of graphitic carbons were easily obtained on silicon wafers through carbonization of nano patterned PPV obtained by the CVD polymerization method. 相似文献
14.
CVD法制备纳米碳管的催化剂多是以Al2O3、SiO2或MgO作载体,Fe、 Ni或Co等过渡族金属为活性组分[1-3]. 相似文献
15.
Kiyoharu Tadanaga Kazuki Iwashita Tsutomu Minami Noboru Tohge 《Journal of Sol-Gel Science and Technology》1996,6(1):107-111
Nylon-6 substrates were coated with SiO2 thin films by the sol-gel method and their water permeability coefficient was evaluated. Methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) were used as starting materials. The addition of MTES to TEOS has enabled the formation of crack-free thin films on the substrates. The thin films strongly adhered to the substrates. The water permeability coefficients of nylon-6 substrates coated with these thin films decreased with the increase in the ratio of TEOS to the total alkoxides. The pretreatment of the nylon-6 substrates with -aminopropyltriethoxysilane was found to be effective to suppress the water permeability. The water permeability was suppressed by about 40% under the optimal condition. 相似文献
16.
The influence of asymmetric catalytic particles prepared by various methods was investigated on the growth of spiral carbon
nanotubes using the CVD method. Asymmetric particles were prepared by either milling or crystallization from oversaturated
solution onto the surface of catalyst support or catalyst impregnation at pH 8–9. As-prepared catalysts were tested in the
decomposition of acetylene. Carbon deposit, thus carbon nanotubes and spirals were observed by transmission electron microscopy
the activity was characterized by carbon yield. 相似文献
17.
Izaskun Bustero García Ainara Obieta Isabel Muñoz Roberto Rincón Inés Arteche Amaya 《Mikrochimica acta》2006,152(3-4):239-247
Interest in carbon nanotubes (CNT) has grown at a very rapid rate in the last decade. Their interesting physical and chemical
properties open attractive possibilities in many application areas. These properties depend on the process conditions during
synthesis and on subsequent purification steps. Recent studies have demonstrated that CNT can promote the electron transfer
of biomolecules. These exceptional properties make them attractive for use in electrochemical biosensors.
Multi walled nanotubes have been synthesized by the Chemical Vapor Deposition (CVD) method using methane as a carbon source
and Ni–Al2O3–SiO2 as the catalyst. The influence of the variation of certain reaction parameters such as feed gas composition, catalyst mass,
temperature and reaction time in the yield of the CVD process has been established. In addition, the structural and chemical
characteristics of the CNTs have been studied and a purification process to eliminate the catalyst and amorphous carbon has
been developed that involves a gaseous oxidative process and acid treatment. The efficiency of the purification step has been
determined by analytical techniques.
Atomic force microscopy, Raman scattering, thermogravimetric analysis, inductively coupled plasma atomic spectroscopy are
the characterization techniques employed in this work. 相似文献
18.
Parameters controlling the removal rate of chemical vapor deposition (CVD) diamond films thermochemically polished on transition
metals in a mixed argon-hydrogen atmosphere were investigated. The ambient temperature, the pressure exerted on the diamond
film, the angular velocity of the polishing plate, the frequency and the amplitude of the transverse vibrations were among
the parameters used in the experiments. Temperature measurements showed that the removal rate was increased exponentially
with increasing magnitude of the parameter. An exponential increase in the removal rate was also observed with increasing
pressure and hence with increasing contact between the diamond film and the polishing plate. However, an exponential decrease
in the removal rate was observed with increasing angular velocity of the polishing plate. The removal rate obtained with the
application of transverse vibrations was more than three times that obtained without transverse vibrations. Moreover, the
removal rate was seen to be higher at resonant frequencies. An increase in the removal rate with increasing amplitude of the
transverse vibrations was also observed. Raman measurements carried out on the films to determine the presence of the non-diamond
carbon layer after thermochemical polishing revealed non-diamond Raman lines only for films polished at 1000 °C and 1050 °C
for the temperature range 750–1050 °C.
Received: 27 October 1999 / Accepted: 2 February 2000 相似文献
19.
纳米CaCO3负载过渡金属CVD法制备多壁碳纳米管的研究 总被引:1,自引:0,他引:1
以纳米碳酸钙粉体为载体,用浸渍法制备了可用于化学气相沉积(CVD)法制备碳纳米管的高产率催化剂.应用FESEM,HRTEM,TEM,XRD和激光拉曼谱对产物进行了表征.结果表明,由于纳米碳酸钙具有较大的比表面积,可高密度地承载催化剂活性组分.在碳纳米管生长初期,处于缓慢分解状态的纳米碳酸钙才能有效地起到载体作用,且反应温度为700~750℃时,碳纳米管的产率较高.Fe-Co双金属催化剂在700℃,催化生长60min后,可增重10倍,而且产物中无定形碳含量极少.纳米碳酸钙载体易于提纯,用质量分数为30%的硝酸超声提纯粗产品1h,可使纯度提高到97%,且不破坏碳纳米管结构. 相似文献
20.
Multilayer graphene/amorphous carbon hybrid films prepared by microwave surface‐wave plasma CVD: synthesis and characterization 下载免费PDF全文
Susumu Ichimura Yasuhiko Hayashi Masayoshi Umeno 《Surface and interface analysis : SIA》2017,49(4):291-296
Hybrid films of multilayer graphene (MG) containing amorphous carbon (a‐C) were synthesized on Al substrates by microwave surface‐wave plasma chemical vapor deposition. Raman scattering and surface transmission electron microscopy showed that the carbon films contained a large quantity of MG when a radio frequency (RF) substrate bias was not applied. Amorphization of graphene in the carbon film was promoted by applying an RF bias, which generated Ar+ in the plasma. The bandgaps of the films were found to increase as the Raman intensity ratios between the 2D‐band (at 2700 cm?1) and D‐band (at 1350 cm?1) decreased, indicating the formation of a‐C. The MG/a‐C all‐sp2 phase of carbon hybrid films exhibited an increase in current density under 5 mW/cm2 of AM1.5G solar simulated irradiation as the RF bias increased because of Ar+‐induced amorphization of the graphene. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献