EFFECT OF ACETYLENE FLOW RATE ON ELECTROSORPTION CAPACITY OF CARBON NANOTUBE AND NANOFIBER COMPOSITE FILM ELECTRODES

2007 ◽  
Vol 14 (01) ◽  
pp. 135-139 ◽  
Author(s):  
X. Z. WANG ◽  
L. K. PAN ◽  
M. G. LI ◽  
Y. W. CHEN ◽  
R. M. CHENG ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Composite Film ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Nanofiber Composite ◽  
Spectra Analysis ◽  
Flow Rates ◽  
Hydrogen Flow ◽  
Successful Removal ◽  
Desalination Technology

Electrosorption of carbon nanotube and nanofiber (CNT–CNF) composite film electrodes was studied as a new desalination technology. The CNT–CNF composite film electrodes were grown on nickel sheets by low pressure thermal chemical vapor deposition. Different growth conditions at different acetylene flow rates of CNT–CNF composite film electrodes have been performed to obtain different crystallinities. The electrosorption experiments and Raman spectra analysis show the successful removal of ions with CNT–CNF composite film electrodes, depending on the optimal degree of crystalline perfection. In our work, optimal electrosorption was realized for the CNT–CNF composite film electrodes growing at 550°C with the acetylene and hydrogen flow rates of 30 and 200 sccm.

The Effects of Hydrogen Flowrate during Pre-Annealing on Graphene Growth by Chemical Vapor Deposition Using Methanol as a Liquid Carbon Precursor

2019 ◽  
Vol 290 ◽  
pp. 107-112
Author(s):  
Raed Abdalrheem ◽  
Fong Kwong Yam ◽  
Abdul Razak Ibrahim ◽  
Khi Poay Beh ◽  
Hwee San Lim ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Light Transmittance ◽  
High Hydrogen ◽  
Flow Rates ◽  
Hydrogen Flow ◽  
Number Of Layers ◽  
Crystallite Sizes ◽  
Grown Graphene

Studying an influence of several parameters on Chemical Vapor Deposition (CVD) used for graphene synthesis is crucial to optimizing the graphene quality to be Compatible with advanced devices. The effect of different hydrogen (H2) flow-rates (0, 50, 100, 150, 200, 250, and 300 sccm) during the pre-annealing process on CVD grown graphene have been reported. This study revealed that hydrogen flow rates during annealing changed the surface roughness/smoothness of the copper substrates. For high hydrogen flow rates, the smoothing effect was increased. Furthermore, the annealed graphene samples emerged a deferent number of layers because of morphological surface changes. According to Raman D- to G-band intensity ratios (ID/IG), the graphene quality was influenced by the annealing hydrogen flowrate. The visible light transmittance values of the grown graphene samples confirmed a few number of layers (mono to seven-layer). Mostly, the samples which annealed under moderate hydrogen flow rates showed less defects intensities and higher crystallite sizes.

Preparation and Characterization of SiC Nanoparticles for ATF-FCM

2018 ◽  
Vol 281 ◽  
pp. 22-27
Author(s):  
Zhao Chen ◽  
Rong Zheng Liu ◽  
Jia Xing Chang ◽  
Ma Lin Liu
Keyword(s):  
Gas Flow ◽  
Chemical Vapor ◽  
Pure Hydrogen ◽  
Fukushima Accident ◽  
Flow Rates ◽  
Sic Nanoparticles ◽  
Hydrogen Flow ◽  
Different Temperatures ◽  
Carrier Gas Flow

Accident Tolerant fuel (ATF) concept was put forward after the Fukushima accident. Among different kinds of ATF, Fully Ceramic Microencapsulated Fuels (FCM) have been paid more and more attention in recent years. SiC matrix is one of the important constituent parts in FCM fuel system, which is sintered from kinds of SiC powders. In this study, SiC nanoparticles were prepared by Fluidized Bed Chemical Vapor Deposition (FB-CVD) method using Hexamethyldisilane (HMDS) as precursor, aimed at reducing the sintering temperature and pressure of FCM-SiC matrix. Experiments of different temperatures with different argon gas ratios were carried out. It was found that good crystal SiC could be obtained from 850°C to 1250°C, under pure hydrogen or H2: Ar=15:1. Different H2 carrier gas flow rate tests were also conducted. With the increase of hydrogen flow rates, the SiC was transformed from 3C-SiC to other types, such as 6H or 15R, but no significant effect was found on particle shape. Based on the characterizations of XRD, SEM and TEM, the results showed the spherical SiC nanoparticles could be obtained as well as 20 nanometers in diameter at the condition of 1150°C, H2: Ar=15:1, under different hydrogen flow rates. Different hydrogen flow rates had little influence on the particle size of SiC nanoparticles.

Characterization of Silicon-Nitride Film Growth by Remote Plasmaenhanced Chemical-Vapor Deposition (Rpecvd)

1993 ◽  
Vol 334 ◽  
Author(s):  
Zhong Lu ◽  
Yi Ma ◽  
Scott Habermehl ◽  
Gerry Lucovsky
Keyword(s):  
Gas Flow ◽  
Film Growth ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Nitride Film ◽  
Silicon Nitride Film ◽  
Flow Rates ◽  
Plasma Generation ◽  
Atom Source ◽  
Rate Ratios

AbstractWe have characterized RPECVD formation of Si-nitride films by relating the chemical bonding in the deposited films to the growth conditions. Gas flow rates for different N- and Si-atom source gases have been correlated with (i) the film stoichiometry, i.e., the Si/N ratio, and the (ii) the growth rate. N2 and NH3 were used as N-atom source gases, and were either delivered (i) up-stream through the plasmageneration tube, or (ii) down-stream. Different flow-rate ratios of NH3/SiH4 were found for deposition of stoichiometric Si-nitride films using up-stream or down-stream introduction of NH3. This is explained in terms of competition between excitation and recombination processes for the N-atom precursor species. Stoichiometric nitride films could not be obtained using the N2 source gas for (i) either up-stream or down-stream delivery, and (ii) for plasma powers up to 50 W. This is attributed to the higher relative binding energy of N-atoms in N2 compared to NH3, and to significant N-atom recombination at high N2 flow rates through the plasma generation region.

Growth Conditions for Carbon Nanotubes and Helical Nanofibers on Copper Substrates Using Sparked Catalysts

2008 ◽  
Vol 55-57 ◽  
pp. 561-564 ◽  
Author(s):  
B. Toboonsung ◽  
Pisith Singjai
Keyword(s):  
Carbon Nanotubes ◽  
Flow Rate ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Argon Flow Rate ◽  
Mixed Gas ◽  
Flow Rates ◽  
Co Catalysts ◽  
Argon Flow ◽  
Fe Catalysts

Carbon nanotubes (CNTs) and helical nanofibers (HNFs) were selectively grown on copper substrates by chemical vapor deposition using acetylene as a carbon source. The experiments were carried out by using Ni, Fe and Co as single and co-catalysts which were deposited onto the substrates by a sparking method. The catalyst-coated copper substrates were heated at 750°C in a mixed-gas-flowing tube furnace, at an argon flow rate of 100 ml/min and various acetylene flow rates of 3, 5 and 10 ml/min. The larger diameter of HNFs was grown only on Ni and Ni-Fe catalysts at the acetylene flow rates of 5 and 10 ml/min whereas the uniform smaller diameter of CNTs was preferentially grown on Fe-Co and Ni-Fe catalysts at the flow rate of 3 ml/min. We suggest that Co likely prevents the formation of HNFs whereas Ni promotes.

Influence of Ethylene and Hydrogen Flow Rates on the Wall Number, Crystallinity, and Length of Millimeter-Long Carbon Nanotube Array

2008 ◽  
Vol 112 (33) ◽  
pp. 12706-12709 ◽  
Author(s):  
Hao Zhang ◽  
Gaoping Cao ◽  
Zhiyong Wang ◽  
Yusheng Yang ◽  
Zujin Shi ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Nanotube Array ◽  
Flow Rates ◽  
Hydrogen Flow ◽  
Carbon Nanotube Array

Microwave plasma-assisted chemical vapor deposition of microcrystalline diamond films via graphite etching under different hydrogen flow rates

CrystEngComm ◽  
2019 ◽  
Vol 21 (15) ◽  
pp. 2502-2507 ◽  
Author(s):  
Kaili Yao ◽  
Bing Dai ◽  
Xiaojun Tan ◽  
Lei Yang ◽  
Jiwen Zhao ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Source ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Flow Rates ◽  
Hydrogen Flow

The growth of microcrystalline diamond films with different hydrogen flow rates via etching graphite as the carbon source was studied.

Sensitivity of germanium content on growth conditions of silicon-germanium nanoparticles prepared in nonthermal capacitively-coupled plasmas

2020 ◽  
Vol 91 (2) ◽  
pp. 20801
Author(s):  
Md. Seraj Uddin ◽  
C. Vijayan ◽  
Jatindra Kumar Rath
Keyword(s):  
Silicon Germanium ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Very High Frequency ◽  
Germanium Content ◽  
Capacitively Coupled ◽  
Hydrogen Flow ◽  
Alloy Nanocrystals ◽  
Coupled Plasmas

We report on the synthesis of Si1−x Ge x alloy nanocrystals by very-high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) technique at different silane to germane gas flow ratio (R) in a mixture of (H2+Ar) dilution gas and H2 dilution gas alone. TEM, SAED, EDS studies and HAADF-STEM mapping of the samples were done to investigate the NCs' size, crystallinity and distribution of Si and Ge in the Si1−x Ge x alloy NCs. The average estimated size of the NCs in all the samples are in the order of exciton Bohr radius of Ge (24.3 nm), thereby indicating the probability of good quantum confinement. The alloy nature of NCs was confirmed in Raman study. The content of Ge in SiGe NCs was evaluated from Raman spectra which show a direct correlation with the fraction of hydrogen flow in the dilution gas mixture.

Study of Growth Kinetics of Ultra-Long Carbon Nanotube Arrays through Wall Number Statistical Investigation

2009 ◽  
Vol 1204 ◽  
Author(s):  
Xinwei Cui ◽  
Weifeng Wei ◽  
Weixing Chen
Keyword(s):  
Gas Phase ◽  
Growth Kinetics ◽  
Chemical Vapor ◽  
Statistical Investigation ◽  
Nanotube Arrays ◽  
Flow Rates ◽  
Hydrogen Flow ◽  
Carbon Nanotube Arrays ◽  
Statistical Studies ◽  
Kinetics Of

AbstractThe unique properties of carbon nanotubes (CNTs) strongly depend on their structures. In this study, the growth kinetics of ultra-long multi-walled CNT (MWCNT) arrays by water-assisted chemical vapor deposition (WACVD) has been investigated based on the statistical studies of CNT wall number. It was found that the kinetics of MWCNT arrays in WACVD demonstrated a lengthening and thickening growth. In the linear lengthening stage, CNT wall number remains constant and catalysts preserve the activity; while in the thickening stage, CNTs thicken substantially through the gas phase-induced thickening process and catalysts start to deactivate. The effects of ethylene and hydrogen flow rates on the MWCNT array growth have also been studied. It was found that by changing ethylene flow rate, different linear lengthening stages corresponding to different CNT wall numbers could be obtained. These findings provide experimental solutions to fabrication MWCNT arrays with both selective heights and controllable wall numbers by WACVD.

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