Improvement in electrochemical capacitance of carbon materials by nitric acid treatment

In this work, to introduce polar functional groups on carbon surfaces, activated carbon fibers (ACFs) were treated by nitric acid in order to enhance the adsorption capacity of propylamine which was one of toxic gases in cigarette smoke. It was found that the polar functional groups were predominantly increased up to 2.0 M of nitric acid, resulting in the increase of total surface acidity. It was found that the adsorption amount of propylamine of the modified ACFs was increased around 17% after a nitric acid treatment. From the XPS results, it was observed that propylamine was reacted with strong or weak polar (acidic) groups, such as COOH, -COO or OH existed on the ACF surfaces.

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Fuming nitric acid treatment of polyethylene. II. The fold surfaces of single crystals

Journal of Polymer Science Part B Polymer Letters ◽

10.1002/pol.1966.110040606 ◽

1966 ◽

Vol 4 (6) ◽

pp. 399-405 ◽

Cited By ~ 30

Author(s):

A. Peterlin ◽

G. Meinel ◽

H. G. Olf

Keyword(s):

Nitric Acid ◽

Single Crystals ◽

Acid Treatment ◽

Fuming Nitric Acid

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The effect of nitric acid (HNO3) treatment on the electrical conductivity and stability of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) thin films

Journal of Polymer Engineering ◽

10.1515/polyeng-2015-0535 ◽

2017 ◽

Vol 37 (2) ◽

pp. 163-168 ◽

Cited By ~ 2

Author(s):

Suhana Mohd Said ◽

Shahriar Mufid Rahman ◽

Bui Duc Long ◽

Subramanian Balamurugan ◽

Norhayati Soin ◽

...

Keyword(s):

Electrical Conductivity ◽

Nitric Acid ◽

Acid Treatment ◽

Base Material ◽

Operating Conditions ◽

Organic Polymer ◽

Visible Range ◽

Infrared Analysis ◽

Conductivity Enhancement ◽

Improved Stability

Abstract In this work, the posttreatment of an organic polymer is performed using an inorganic acid, nitric acid (HNO3). We picked poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the base material and improved its electrical conductivity by acid treatment with different concentrations of HNO3. The acid treatment was able to achieve the optimum electrical conductivity of 197 S/cm, which is 115.5 times higher than the base material when treated with an aqueous solution containing 65% of HNO3. Moreover, the films showed higher transparency in the visible range while conducting Fourier transform infrared analysis. In addition, the treated films showed improved stability against outdoor operating conditions in terms of sheet resistance compared with untreated PEDOT:PSS films. We tried to develop a hypothesis to describe the reason behind the electrical conductivity enhancement by studying the thicknesses of all the samples at different acid concentration levels. The results from atomic force microscopy, the Hall effect, and the trend of film thickness suggest that the conformational change, the removal of excess PSS from the polymer, and the increase in carrier concentration are the reasons behind the improvement in electrical conductivity.

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Influence of Nitric Acid Treatment in Different Media on X-ray Structural Parameters of Coal

Energy & Fuels ◽

10.1021/ef800424w ◽

2008 ◽

Vol 22 (6) ◽

pp. 4087-4091 ◽

Cited By ~ 5

Author(s):

Sudip Maity ◽

Ashim Choudhury

Keyword(s):

Nitric Acid ◽

Acid Treatment ◽

Structural Parameters ◽

X Ray

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Synthesis of P- and N-doped carbon catalysts for the oxygen reduction reaction via controlled phosphoric acid treatment of folic acid

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.10.148 ◽

2019 ◽

Vol 10 ◽

pp. 1497-1510 ◽

Cited By ~ 1

Author(s):

Rieko Kobayashi ◽

Takafumi Ishii ◽

Yasuo Imashiro ◽

Jun-ichi Ozaki

Keyword(s):

Folic Acid ◽

Phosphoric Acid ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Acid Treatment ◽

Carbon Materials ◽

Reduction Reaction ◽

P Content ◽

Orr Activity ◽

Carbon Catalysts

Herein, we synthesized P- and N-doped carbon materials (PN-doped carbon materials) through controlled phosphoric acid treatment (CPAT) of folic acid (FA) and probed their ability to catalyze the oxygen reduction reaction (ORR) at the cathode of a fuel cell. Precursors obtained by heating FA in the presence of phosphoric acid at temperatures of 400–1000 °C were further annealed at 1000 °C to afford PN-doped carbon materials. The extent of precursor P doping was maximized at 700 °C, and the use of higher temperatures resulted in activation and increased porosity rather than in increased P content. The P/C atomic ratios of PN-doped carbon materials correlated well with those of the precursors, which indicated that CPAT is well suited for the preparation of PN-doped carbon materials. The carbon material prepared using a CPAT temperature of 700 °C exhibited the highest ORR activity and was shown to contain –C–PO2 and –C–PO3 moieties as the major P species and pyridinic N as the major N species. Moreover, no N–P bonds were detected. It was concluded that the presence of –C–PO2 and –C–PO3 units decreases the work function and thus raises the Fermi level above the standard O2/H2O reduction potential, which resulted in enhanced ORR activity. Finally, CPAT was concluded to be applicable to the synthesis of PN-doped carbon materials from N-containing organic compounds other than FA.

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Modified Carbon Papers as Electrode Materials of all-Vanadium Redox Flow Battery

MRS Proceedings ◽

10.1557/opl.2013.615 ◽

2013 ◽

Vol 1492 ◽

pp. 15-23

Author(s):

Chih-Hsing Leu ◽

Shu-Yuan Chuang ◽

Kan-Lin Hsueh ◽

Jia-Ming Huang ◽

Chia-Chun Chung ◽

...

Keyword(s):

Energy Efficiency ◽

Binding Energy ◽

Redox Reaction ◽

Acid Treatment ◽

Electrode Materials ◽

Carbon Materials ◽

Vanadium Redox Flow Battery ◽

Hydrolysis Reaction ◽

Ozone Treatment ◽

The Stability

ABSTRACTThe electrode materials for VRFB should possess higher electric conductivity, corrosion resistance and hydrophilic properties in sulfuric acid. The characteristics of the electrode materials affect the stability and the energy efficiency of VRFB. Carbon materials are the best suited for VRFB applications. In this study, the calcined treatment, acid treatment and ozone treatment were used to modify the surface of carbon papers. The redox reaction of [VO]2+/[VO2]+ on the modified carbon papers was evaluated by cyclic voltammetry (CV). The surface compositions of carbon materials were analyzed by X-ray photoelectron spectrometry (XPS). The experimental results reveal that three oxidative methods enhance the redox reaction of [VO]2+/[VO2]+. The calcined treatments and acid treatments also enhanced hydrolysis reaction. The mole ratio of O/C apparently increased, but the binding energy of C1s and O1s were not chemically shifted in the acid treatment. The intensity of binding energy of O1s, between 532 eV and 534 eV, apparently increased in the ozone and calcined treatments. The Ox treated samples were more hydrophilic than the Oz treated samples. In the Ox treated samples, the decrease of Rct value indicates that was contributed from the redox reaction of [VO]2+/[VO2]+ and hydrolysis reaction. It does not completely benefit the energy efficiency of VRFB. The 5 x 5 cm2 modified carbon papers were used as electrode materials in the VRFB. The voltage efficiency, coulomb efficiency and energy efficiency reached 93 %, 90 % and 83 %, respectively, at a current density of 12 mA．cm-2 at 0.8-1.8 V.

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Preparation of Low-Sulfur Expanded Graphite with Different Size Particles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.745 ◽

2013 ◽

Vol 652-654 ◽

pp. 745-748 ◽

Cited By ~ 1

Author(s):

Chun Yu Wang ◽

Huan Ran Li ◽

Chun Lin Qin ◽

Peng Zhang

Keyword(s):

Sulfuric Acid ◽

Nitric Acid ◽

Acid Treatment ◽

Engineering Application ◽

Expanded Graphite ◽

Mixture Ratio ◽

Sulfuric Acid Treatment ◽

Low Sulfur

In this paper, results shows that expanded graphite of 128mL/g could be produced under the nitric acid treatment with the optimum mixture ratio of graphite: HNO3: H2O2: KMnO4 being 1(g):6(ml):2(ml):0.02(g), compared with the 145ml/g under the sulfuric acid treatment (graphite: H2SO4: H2O2 =1(g):3(ml):2 (ml)). The sulfur contents are ~0.10wt.% in EG with nitric acid treatment, and ~0.24wt.% in EG with sulfuric acid treatment, respectively. Therefore, the nitric acid treatment EG has little sulfur, which is greatly demanded in engineering application.

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