Purification of single-wall carbon nanotubes

Shi, Zujin; Lian, Yongfu; Liao, Fuhui; Zhou, Xuhao; Gu, Zhennan; Zhang, Yuegang; Iijima, Sumio

doi:10.1016/s0038-1098(99)00278-1

Cited by 211 publications

(128 citation statements)

References 10 publications

Supporting

Mentioning

117

Contrasting

Unclassified

Order By: Relevance

“…Only one oxidative peak is observed for all photocatalysts investigated, while for CNTs, a gradually increased intensity signal without oxidation peak was obtained. 38 This oxidative peak may attribute to the oxidation reaction of Ag(0) to Ag 2 O, which further confirms the existence of Ag(0) in all Ag/AgXCNTs samples. The oxidation peak temperatures of Ag/AgClCNTs, Ag/AgBr-CNTs, and Ag/AgI-CNTs photocatalysts are 550, 549, and 516°C, respectively, indicating that the oxidation temperature of Ag/AgI-CNTs is the lowest among the three photocatalysts.…”

Section: ■ Experimental Sectionsupporting

confidence: 64%

Synthesis and Characterization of Novel Plasmonic Ag/AgX-CNTs (X = Cl, Br, I) Nanocomposite Photocatalysts and Synergetic Degradation of Organic Pollutant under Visible Light

Shi

Chen

et al. 2013

ACS Appl. Mater. Interfaces

152

View full text Add to dashboard Cite

A series of novel well-defined Ag/AgX (X = Cl, Br, I) loaded carbon nanotubes (CNTs) composite photocatalysts (Ag/AgX-CNTs) were fabricated for the first time via a facile ultrasonic assistant deposition−precipitation method at the room temperature (25 ± 1°C). X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption−desorption analysis, scanning electron microscopy, and ultraviolet−visible light absorption spectra analysis were used to characterize the structure, morphology, and optical properties of the asprepared photocatalysts. Results confirmed the existence of the direct interfacial contact between Ag/AgX nanoparticles and CNTs, and Ag/AgX-CNTs nanocomposites exhibit superior absorbance in the visible light (VL) region owing to the surface plasmon resonance (SPR) of Ag nanoparticles. The fabricated composite photocatalysts were employed to remove 2,4,6-tribromophenol (TBP) in aqueous phase. A remarkably enhanced VL photocatalytic degradation efficiency of Ag/AgX-CNTs nanocomposites was observed when compared to that of pure AgX or CNTs. The photocatalytic activity enhancement of Ag/AgX-CNTs was due to the effective electron transfer from photoexcited AgX and plasmon-excited Ag(0) nanoparticles to CNTs. This can effectively decrease the recombination of electron−hole pairs, lead to a prolonged lifetime of the photoholes that promotes the degradation efficiency. KEYWORDS: plasmonic photocatalyst, carbon nanotube supporter, silver halides, visible light, photocatalytic activity ■ INTRODUCTIONPhotocatalysis technique, as a cost-effective means for solar energy utilization, hydrogen production, and environmental purification, has been focused by many researchers. 1−7 In recent years, highly efficient visible-light-driven (VLD) photocatalyst development has been recognized as an important goal in the field of photocatalysis. Generally, two major approaches have been frequently employed to fabricate VLD photocatalyst. One is to modify TiO 2 -based photocatalyst to extend the light absorption spectrum from the UV to VL region by elements doping, 2 noble metal deposition, 3,8 12 Despite the noticeable progress, these VLD photocatalysts still have some drawbacks, such as relatively low VL photocatalytic activity and poor stability, limiting their practical applications. It is therefore highly desirable to develop highly efficient VLD photocatalysts that could meet the needs for applications in environmental and energy fields.Currently, the localized surface plasmon resonance (SPR) effect of noble-metal nanoparticles (e.g., Ag and Au) has become a research focus in the development of VLD photocatalysts. 13 The VL activity of plasmonic photocatalyst is originated from the distinctive plasmon resonance effect in VL region that has been well demonstrated for metallic Au and Ag nanoparticles. 4,14−19 Also a number of Ag/AgX (X = Cl, Br)-based materials, such as graphene sheets grafted Ag/AgCl, 1 graphene oxide (GO) enwrapped Ag/AgX (X = Cl, Br) nanocomposite, 16 Ag/AgBr@TiO 2 , 18 Ag/AgCl@H 2 WO...

show abstract

Section: ■ Experimental Sectionsupporting

confidence: 64%

Synthesis and Characterization of Novel Plasmonic Ag/AgX-CNTs (X = Cl, Br, I) Nanocomposite Photocatalysts and Synergetic Degradation of Organic Pollutant under Visible Light

Shi

Chen

et al. 2013

ACS Appl. Mater. Interfaces

152

View full text Add to dashboard Cite

show abstract

“…Nevertheless, it is still a challenging problem to purify the reaction product without damaging the tubes. Many methods have been developed for purification of SWNTs, including hydrothermal treatment [7], gaseous or catalytic oxidation [8,9], nitric acid reflux [10 12], peroxide reflux [13], cross-flow filtration [14], and chromatography [15]. Purifications based on Nano Res (2009)2: 865 871 DOI 10.1007/s12274-009-9087-7 Research Article an initial selective oxidation to remove amorphous carbon (and not induce serious loss of SWNTs), followed by refluxing in a concentrated acid with stronger oxidizing properties such as nitric acid, have also been found to be effective in removing metal catalysts from the reaction products [16 18].…”

Section: Introductionmentioning

confidence: 99%

Minimizing purification-induced defects in single-walled carbon nanotubes gives films with improved conductivity

et al. 2009

View full text Add to dashboard Cite

A method for the non-destructive purification of single-walled carbon nanotubes (SWNTs) using classical coordination chemistry to remove the metal catalyst has been developed. In preliminary tests, the conductivity of fi lms based on the resulting SWNTs was markedly better than that of fi lms prepared from SWNTs purifi ed by treatment with oxidizing acid solutions. The transparent and conducting SWNT fi lms have potential applications in optoelectronic devices.

show abstract

“…Techniques such as gas phase or thermal annealing in air or oxygen has been used [10][11][12] in order to remove amorphous carbons and other carbon nanoparticles such as fullerenes that are found in SWCNT soot. In addition, liquid-phase reactions in various acids or corrosive solvents [13][14][15][16][17][18] have been used to remove the metal catalysts required from the synthesis of SWCNTs. Other purification techniques include ultrasonication, centrifugation, and filtration [19,20].…”

Section: Introductionmentioning

confidence: 99%

Purification of single-walled carbon nanotubes

Yaya

Ewels

Wagner

et al. 2011

Eur. Phys. J. Appl. Phys.

View full text Add to dashboard Cite

Abstract. We present a study of purification of single-walled carbon nanotubes (SWCNTs) using different oxidation temperatures and chemical treatments. We have developed a simple two annealing-steps procedure resulting in high nanotube purity with minimal sample loss. The process involves annealing the SWCNTs at 300 • C for 2 h with subsequent reflux in 6 M HCl at 130 • C, followed by further annealing at 350 • C for 1 h with reflux in 6 M HCl at 130 • C. The process results in effective removal of carbon impurities and metal particles which are associated with SWCNTs production. The process is less time consuming (complete in 4.5 h) than conventional acid purification methods which require over 5 h, and less destructive than conventional methods with a yield of 26%. SWCNT purity was assessed using Raman spectroscopy, thermogravimetry and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy.

show abstract

Purification of single-wall carbon nanotubes

Cited by 211 publications

References 10 publications

Synthesis and Characterization of Novel Plasmonic Ag/AgX-CNTs (X = Cl, Br, I) Nanocomposite Photocatalysts and Synergetic Degradation of Organic Pollutant under Visible Light

Synthesis and Characterization of Novel Plasmonic Ag/AgX-CNTs (X = Cl, Br, I) Nanocomposite Photocatalysts and Synergetic Degradation of Organic Pollutant under Visible Light

Minimizing purification-induced defects in single-walled carbon nanotubes gives films with improved conductivity

Purification of single-walled carbon nanotubes

Contact Info

Product

Resources

About