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    Present advancement in production of carbon nanotubes and their derivatives from industrial waste with promising applications
    (2017-01-01)
    Kerdnawee, Konrat
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    Termvidchakorn, Chompoopitch
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    Yaisanga, Pacharaporn
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    Pakchamsai, Jirapat
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    Chookiat, Cheewapon
    An increase in global consumption has led to an exponential increase in industrial production activities which inevitably results in overwhelming remain of industrial waste. Consequently it has driven increasing attentions of research and development teams in various countries to propose and investigate novel methodologies to utilize such industrial waste. Instead of using as alternative energy sources, usage of industrial waste for production of carbonaceous nanomaterials has been examined via various routes, such as catalytic pyrolysis, hydrothermal treatment and so on. Meanwhile, for sustainable and secure continuity of the carbonaceous nanomaterial production, broad spectra of promising applications have also been examined. Among those emerging applications, utilization of carbonaceous nanomaterials in pollution control and prevention has been focused worldwide. Therefore, in this review, relevant research works focusing on catalytic pyrolysis of carbonaceous industrial waste for carbonaceous nanomaterial production were comprehensively analyzed and summarized. In addition, promising applications involving with antibiotic removal, spilled oil handling and pollutant gas detection were also reviewed.
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    Hybrid gas sensor based on platinum nanoparticles/poly(methyl methacrylate)-coated single-walled carbon nanotubes for dichloromethane detection with a high response magnitude
    (2016-05-01)
    Muangrat, Worawut
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    Yordsri, Visittapong
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    Maolanon, Rungroj
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    Pratontep, Sirapat
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    Porntheeraphat, Supanit
    A dichloromethane (DCM) sensor with a high response magnitude was successfully fabricated using the integration of single-walled carbon nanotubes (SWNTs), poly(methyl methacrylate) (PMMA) and platinum nanoparticles (Pt NPs). A pristine SWNT network was first formed by drop-casting onto printed circuit board (PCB) substrates. Next, PMMA was coated onto the pre-dropped SWNT network by spin coating using a PMMA-toluene solution, followed by the deposition of Pt NPs by electron-beam evaporation (hereafter referred to as Pt/PMMA/SWNT). The Pt/PMMA/SWNT enabled an approximately 69-fold improvement in DCM detection compared to pristine SWNT. The high response magnitude of the Pt/PMMA/SWNT was successfully achieved because of the incorporation of PMMA and Pt functions. Swelling of the PMMA matrix as a result of DCM adsorption leads to PMMA volume expansion, thereby increasing the SWNT-SWNT distance, which results in an increase in the resistance. Pt NPs promote the dissociation of DCM to CO, and consequently the CO oxidation on the Pt NPs catalyst and electron donation from Pt NPs to SWNTs, resulting in an increase in the resistance. Moreover, a linear relationship was obtained between the sensor response of the Pt/PMMA/SWNT and the concentration of DCM. These results suggest that the integration of SWNTs with PMMA and Pt NPs is a promising approach for improving DCM detection at room temperature.
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    Hybrid graphene and poly(methyl methacrylate) for gas sensor application
    (2017-01-01)
    Rattanabut, Chanoknan
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    Muangrat, Worawut
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    Phonyiem, Mayuree
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    Bungjongpru, Win
    ;
    The graphene and hybrid graphene/poly(methy methacrylate) (PMMA) were fabricated for use in volatile organic compound (VOC) detection. Graphene was synthesized on copper foil by chemical vapor deposition (CVD). To remove Cu foil, PMMA was coated on graphene by spin-coating (hereafter referred to as graphene/PMMA) and transferred to silicon substrate with silicon dioxide layer (SiO<inf>2</inf>/Si) by wetting transfer process. For comparison, a PMMA layer was removed in order to achieve a pristine graphene. Graphene and hybrid graphene/PMMA sensors showed the highest sensor response to ethanol. Responses of the graphene to ethanol, dichloromethane and benzene were 5.62, 20.06 and 35.09 times higher than that of hybrid graphene/PMMA. The sensor response of graphene can be described in terms of the dielectric constant of VOC. In addition, the sensor response of hybrid graphene/PMMA to benzene and dichloromethane would be attributed to the Hansen solubility parameter (HSP), while that of ethanol is related to the molecular size. These results suggest that the integration of graphene with PMMA is a promising approach for the selectivity for VOC detection.
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    Field emission properties of a DWCNT bundle and a single MWCNT
    (2018-02-01)
    Fujishige, Masatsugu
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    Muramatsu, Hiroyuki
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    Takeuchi, Kenji
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    Arai, Susumu
    The field emission properties of a bundle of double-walled carbon nanotubes (DWCNTs) and a single multiwalled carbon nanotube (MWCNT) were investigated. A DWCNT bundle or a single MWCNT was attached to the head of sharpened tip of tungsten by electrophoresis; the tungsten tip was dipped into a drop of a carbon nanotube/1,2-dichloroethane suspension on a stainless plate, and a high-frequency AC voltage (20 V peak to peak with a frequency of 15 MHz) was applied between the tungsten tip and the stainless steel plate. The turn-on fields of the DWCNT and MWCNT tips for 1 nA/cm<sup>2</sup> were 0.05 and 0.48 V/μm, respectively. From the Fowler-Nordheim plots, the field enhancement factor (β) of the tips was estimated to be 109,600 (DWCNT) and 6780 (MWCNT). The present DWCNT emitter is characterized by a very small turn-on field and large β. The field emission performance is discussed in terms of the sizes of the bundle of DWCNTs and a single MWCNT.
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    Hydrogen sensing properties of protective-layer-coated single-walled carbon nanotubes with palladium nanoparticle decoration
    (2011-02-04) ;
    Okabayashi, Y.
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    Minami, S.
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    Itabashi, K.
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    Ueda, T.
    Protective-layer-coated single-walled carbon nanotubes (SWNTs) with palladium nanoparticle decoration (Pd-SiO<inf>2</inf>-SWNTs) were fabricated and their sensing properties for hydrogen (H<inf>2</inf>) were investigated. SWNTs were coated with a 3-4 nm thick SiO<inf>2</inf> layer by pulsed laser deposition and subsequently decorated with Pd nanoparticles by electron beam evaporation. Even though the SWNTs were completely surrounded by a protective layer, Pd-SiO<inf>2</inf>-SWNTs responded to H<inf>2</inf> down to a concentration of 1 part per million. Compared with the Pd nanoparticle-decorated SWNTs without a protective layer (Pd-SWNTs), Pd-SiO<inf>2</inf>-SWNTs exhibited highly stable sensor responses with variations of less than 20%; Pd-SWNTs showed a variation of 80%. The density of the Pd-SWNTs significantly decreased after the sensing test, while that of the Pd-SiO<inf>2</inf>-SWNTs with the netlike structure remained unchanged. The hydrogen sensing mechanism of the Pd-SiO <inf>2</inf>-SWNTs was attributed to the chemical gating effect on the SWNTs due to dipole layer formation by hydrogen atoms trapped at the Pd-SiO<inf>2</inf> interface. Moreover, the relationship between H<inf>2</inf> concentration and sensor response can be described by the Langmuir isotherm for dissociative adsorption. © 2011 IOP Publishing Ltd.
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    Effect of metal catalysts on synthesis of carbon nanomaterials by alcohol catalytic chemical vapor deposition
    (2013-12-31)
    Muangrat, Worawut
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    Porntheeraphat, Supanit
    ;
    Carbon nanomaterials (CNMs) were synthesized by alcohol catalytic chemical vapor deposition (CVD) at atmospheric pressure using different metal catalysts (Ni, Co and Fe) at a growth temperature of 700°C. Ni and Fe acted as active catalysts for multi-walled carbon nanotubes (MWNTs) growth, while Co acted as an active catalyst for bamboo-like MWNTs and carbon nanofibers (CNFs) growth. The CNMs synthesized from Ni catalyst showed the highest crystallinity with a small amount of by-products. These results imply that metal catalyst is a key parameter to the structure, morphology and crystallinity of CNMs. The different effects of metal catalysts on the growth of CNMs can be explained in terms of the difference in the change in Gibbs free energy of metal carbide formation.
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    Investigation on electrochemical properties of sugarcane leaves-derived activated carbon by steam activation
    (2020-01-01)
    Ukkakimapan, Pundita
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    Ukakimaparn, Prapart
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    Wanchaem, Thanthamrong
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    Yordsri, Visittapong
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    Sattayarut, Vichuda
    Sugarcane leaves (SLs) are a bio-waste from sugar production industry. To explore the value-added SLs, the SLs were used raw materials of activated carbons (ACs) by steam activation and their electrochemial properties were investigated for supercapacitor applications. The synthesis of ACs from the SLs consisted of two steps; carbonization at 500ºC and steam activation. The synthesis condition was optimized by varying activation temperature (800 and 850ºC) The porous structures were thoroughly formed on the surface after steam activation and the surface areas were reached to 630 and 639 m<sup>2</sup> g<sup>-1</sup> at the activation temperature of 800 and 850ºC, respectively. The SLs-derived ACs activated at 800ºC assembled in coin cell using organic electrolyte showed the highest specific capacitance of approximately 16 F g<sup>-1</sup> with a capacitance retention of 62% when the current density increased to 1.5 A g<sup>-1</sup>. Even though there is a room to improve the electrochemical properties such as optimization of porosity and removal of inorganic component, the SLs show a potential use as raw materials of ACs for supercapacitor applications.
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    Multifunctional Solvent Molecule Realizing High-Performance Elastic Polymer Electrolytes for Lithium Metal Batteries
    (2025-11-26)
    Nipatwarakan, Pimchanok
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    Song, Junlin
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    Cui, Yujie
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    Guo, Decai
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    Song, Yongyi
    Solid-state polyurethane electrolytes offer excellent elasticity, which can significantly improve the interfacial ion transport of solid-state lithium metal batteries. However, pure polyurethane electrolytes suffer from poor Li<sup>+</sup> conductivity. Herein, a multifunctional solvent molecule, trifluoro-N,N-dimethylacetamide (TFDMA), is introduced to modify the thermoplastic polyurethane (TPU) electrolyte, resulting in a composite electrolyte (TPU-TFDMA) with both high mechanical properties and good Li<sup>+</sup> transport performance (ionic conductivity = 1.53 × 10<sup>–3</sup> S cm<sup>–1</sup> and Li<sup>+</sup> transference number = 0.50). Experimental characterizations and theoretical simulations reveal that the presence of additional hydrogen-bonding interactions between TFDMA and the TPU chains not only maintains the mechanical strength of TPU but also enhances interfacial stability and effectively inhibits lithium dendrite growth. Furthermore, TFDMA promotes lithium salt dissociation and reduces the coordination between solvent molecules and Li<sup>+</sup>, facilitating Li<sup>+</sup> desolvation and rapid diffusion. TFDMA also immobilizes TFSI<sup>–</sup>, thereby enhancing Li<sup>+</sup> transport efficiency and contributing to the formation of stable and multifunctional interfaces between electrodes and electrolytes. Consequently, the TPU-TFDMA electrolytes enable the Li symmetric cell to stably work for over 2500 h and endow the LiFePO<inf>4</inf> full cell with a reversible capacity of 130 mAh g<sup>–1</sup> after 320 cycles at 0.5 C.
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    Adsorption kinetics of NO2 on single-walled carbon nanotube thin-film sensor
    (2008-10-01) ;
    Inoue, Satoshi
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    Honda, Shin ichi
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    Katayama, Mitsuhiro
    The adsorption kinetics of NO<inf>2</inf> on a single-walled carbon nanotube (SWNT) thin-film sensor was investigated. To avoid the influence of ambient air, the adsorption property of SWNTs was explored under high vacuum. By virtue of the suppression of the influence of residual gases and the cleanness of the SWNT surface in vacuum, the SWNTs exhibited high sensitivity with a detection limit of lower than 1 ppb. On the basis of the Langmuir adsorption isotherm, the sticking probability and adsorption energy of NO<inf>2</inf> molecules on SWNTs were experimentally estimated. © 2008 The Japan Society of Applied Physics.
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    A flexible formaldehyde sensor based on palladium nanoparticles-polyvinylpyrrolidone-carbon nanotubes-nanocellulose composite films
    (2025-01-01)
    Chobsilp, Thanattha
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    Muangrat, Worawut
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    Inpaeng, Saowaluk
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    Tedsree, Karaked
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    Yordsri, Visittapong
    A flexible formaldehyde sensor with high sensitivity was successfully fabricated by integrating palladium (Pd) nanoparticles, polyvinylpyrrolidone (PVP), multi-walled carbon nanotubes (MWCNTs) and nanocellulose (NC) into composite films. The flexible composite films were fabricated via vacuum filtration. The morphology, structure, composition, crystallinity, and functional group of as-fabricated sensing materials were characterized by scanning electron microscopy, transmission electron microscopy, electron probe microanalyzer, Raman spectroscopy, and Fourier transform infrared spectrometer. Pd nanoparticles-PVP-MWCNTs-NC (Pd-PVP-MWCNTs-NC) composite films exhibited an 11-fold increase in formaldehyde sensitivity compared to MWCNTs-NC composite films. The excellent sensing performances of Pd-PVP-MWCNTs-NC sensors were attributed to the combination of Pd nanoparticles and PVP. The enhanced sensitivity is attributed to the synergistic effect of the high electron transfer from formaldehyde molecule to Pd nanoparticles and swelling of PVP due to sorption of formaldehyde molecule. Pd-PVP-MWCNTs-NC sensors still maintained good response under bending angle up to 30° and 300 bending cycles. The results demonstrate that the Pd-PVP-MWCNTs-NC composite films are highly promising in terms of sensitivity and flexibility for sub-ppm level formaldehyde detection at room temperature.