Changes in the properties of fibrous nanocarbons during high temperature heat treatment

Kuvshinov, G. G.; Chukanov, I. S.; Krutsky, Y.L.; Ochkov, V. V.; Зайковский, В. И.; Kuvshinov, Dmitriy

doi:10.1016/j.carbon.2008.09.052

Cited by 29 publications

(12 citation statements)

References 30 publications

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“…The bamboo-like structures, 50-120 nm in diameter, are expected to grow from larger NPs (>45 nm in diameter). The difference in their growth mechanism, as compared to MWCNTs, induces a strong curvature with chain-like morphology that has some similarities to CNFs [36]. Initially, a higher amount of small NPs, a lower activity of large NPs, and limited growth time were the reasons for much higher amount of MWCNTs than bamboo-like CNFs on the substrates (Figure 3(a)) [37].…”

Section: Characterization Of Catalytic Nanoparticles and Carbonmentioning

confidence: 99%

Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films

et al. 2018

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The ammonia adsorption on the nanostructured carbon thin film was significantly influenced by the choice of deposition temperature and deposition time of thin film synthesis. The thin films were prepared on Si/SiO2 substrates by chemical vapour deposition in Ar/C2H2 gas mixture using iron catalytic nanoparticles. The analysis of the grown layer by the scanning and transmission electron microscopy showed the transition from long multiwalled nanotubes (MWCNTs) to bamboo-like hollow carbon nanofiber structure with the decrease of the deposition temperature from 700 to 600°C. Further, the material was analyzed by energy-dispersive X-ray spectroscopy and Raman spectroscopy confirmed the transition from graphitic sp2 structure to highly defective structure at lower deposition temperature. The resistance of the prepared layer strongly depends on deposition temperature (Td) and deposition time (td). High resistance layer, 38.6 kΩ, was formed at Td 600°C and td 10 min, while at Td 700°C and td 60 min, the resistance decreased to 860 ohms. Such behaviour is consistent with MWCNTs being responsible for the formation of the conductive network. Such system was studied using chemiresistor ammonia gas sensor configuration. The sensor resistance increased when exposed to ammonia in all the cases, but their response varied considerably. A decrease in deposition time, from 60 to 10 min, and the deposition temperature, from 700 to 600°C, led to the 10-fold increase in the sensor response. The measurements carried out at room temperature showed the higher sensor response than the measurements carried out at 200°C. This behaviour can be explained by the change in adsorption-desorption equilibrium at different temperatures. Analysis of dependence of the sensor response on the ammonia concentration proved that the underlying resistance change mechanism is chemisorption of ammonia molecules on the carbon network corresponding to the Langmuir isotherm.

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Section: Characterization Of Catalytic Nanoparticles and Carbonmentioning

confidence: 99%

Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films

et al. 2018

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“…The porosity is mainly due to the presence of mesopores although there are a few micropores as well. The mesopores are formed by the hollow space in the nanofiber interior and in their interlacing, whereas the micropores are created because of defects on the surface of the filaments [29]. The HTT of the BCNFs leads to a substantial decrease of the surface area and porosity, i.e.…”

Section: Figmentioning

confidence: 99%

Graphitic nanomaterials from biogas-derived carbon nanofibers

Cuesta

Cameán

Ramos

et al. 2016

Fuel Processing Technology

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Carbon nanofibers with different microstructure and elemental composition that were produced in the catalytic decomposition of synthetic biogas mixtures, in a rotary-bed reactor using nickel and nickel-cobalt catalysts at 600 ºC and 700 ºC, were heat treated in the temperature interval 2600-2800 ºC to explore their ability to graphitize. The influence of treatment temperature as well as carbon nanofibers composition, particularly metallic species, on the structural and textural properties of the materials prepared is discussed. Graphitic nanomaterials with great development of the three-dimensional structure (d 002 ~ 0.3360 nm, L c ~ 48 nm, L a ~ > 100 nm) and low porosity (S BET ~ 20 m 2 g -1 ) have been achieved. Because of the catalytic effect of silicon in the presence of inherent nickel and cobalt metals, more structurally ordered materials were obtained from the carbon nanofibers by adding silica. Based on the results of this work, the utilization of biogasderived carbon nanofibers for the production of synthetic nanographite to be used in different applications, such as electrode material in energy storage devices in which both high degree of graphitic order and small surface area are required, appears feasible.

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“…3D nitrogen-doped porous CNFs can be prepared using our CNF gel without adding any activation as the electrodes of supercapacitors, which exhibit hierarchical structure with reasonable distribution of mesopores and micropores. Compared to the carbon materials with single-sized pores, the [57][58][59][60][61][62][63][64]72] High surface areas; low volume density Thermal transformation approach CNF gels derived from thermal transformations of BC [16,70,85,86,[102][103][104][105][106][107][108][109][110][111][112][113] CVD technique 3D CNF/graphene networks [116] 3D CNF films Template-assisted approach Carbon cloth, carbon papers and carbon fiber felt-based 3D CNF films [128][129][130][131][132][133][134][135][136][137][139][140][141][142][143][144][145][146][147]…”

Section: Supercapacitorsmentioning

confidence: 99%

“…Finally, it should be noted that the variables during the thermal transformation procedure, such as the heating/cooling rates, standing temperature and time, and reaction atmosphere can tailor the pore structures of the obtained CNFs, thereby significantly affecting their properties . Hence, it is necessary to control these parameters for optimizing high‐performance 3D CNFs.…”

Section: Preparation Of 3d Cnfs and Their Composite Nanostructuresmentioning

confidence: 99%

Macroscopic‐Scale Three‐Dimensional Carbon Nanofiber Architectures for Electrochemical Energy Storage Devices

Chen

Feng

Liang

et al. 2017

Advanced Energy Materials

170

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Therefore, it is necessary to develop highperformance energy storage devices for facilitating the effective utilization of intermittent renewable energy sources. [7][8][9] Among varieties of electrochemical energy storage devices, supercapacitors (known as electrochemical capacitors) [10,11] and some rechargeable batteries (lithium-ion batteries (LIBs), lithiumsulfur (Li-S) batteries, and metal-O 2 batteries) [12][13][14][15] are at the frontier, because they can transport high power and store high energy. Nowadays, they play an indispensable role in our daily life by powering numerous portable electronic devices (e.g., cell phones and laptops), hybrid electric vehicles, and large-scale electrical grids. [16][17][18][19] It is well accepted that the performance of energy storage devices mainly depended on their electrode materials. [20,21] Owing to the advantages of large surface area, light weight, good electrical conductivity, and high thermal/ chemical stability, carbon materials have been considered as the most important electrode materials of supercapacitors and rechargeable batteries [8,20,21] Hence, various nanostructured carbons, such as carbon/graphene quantum dots, [22,23] carbon nanofiber (CNFs), [16,24] carbon nanotubes (CNTs), [13,25] graphene [26][27][28][29][30][31][32] carbon nanosheets, [33,34] 3D carbon nanostructures, [35][36][37] and porous carbon, [38,39] have gained great attention. Among these materials, 3D carbon nanomaterials have some advantages. The interlinked architecture not only shortens transport distances for ions in the well-interconnected wall structure, but also provides a continuous pathway endowing for the fast electron transport. [40] Moreover, the structural interconnectivities guarantee higher electrical conductivity and better mechanical stability. [36,41] Thereby, the design and fabrication of various 3D carbonbased nanostructures, including carbon nanotube networks, graphene gels, graphene foams, and 3D CNFs, have been intensively investigated.Over the past few years, there are many reviews summarizing the progress of fabricating 3D carbon-based nanomaterials. For example, Schneider et al. overviewed the recent advance in the synthesis of 3D arranged carbon nanotube architectures. [42] Li et al. reviewed the carbon-based 3D nanostructures for supercapacitors. [36] Cao and Gui et al. comprehensively reviewed the recent progress in synthesis, properties, and energy applications of CNT sponges, aerogels, and hierarchical composites. [43] The development of high-performance electrochemical energy storage devices is critical for addressing energy crises and environmental pollution.

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Changes in the properties of fibrous nanocarbons during high temperature heat treatment

Cited by 29 publications

References 30 publications

Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films

Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films

Graphitic nanomaterials from biogas-derived carbon nanofibers

Macroscopic‐Scale Three‐Dimensional Carbon Nanofiber Architectures for Electrochemical Energy Storage Devices

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