Structure and electrochemical properties of carbon aerogels polymerized in the presence of Cu2+

Yoshizawa, Noriko; Hatori, Hiroaki; Soneda, Yasushi; Hanzawa, Yohko; Kaneko, Katsumi; Dresselhaus, M. S.

doi:10.1016/j.jnoncrysol.2003.08.041

Cited by 54 publications

(40 citation statements)

References 29 publications

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“…the density, and Z and M, the atomic number and mass, respectively). It follows that the ratio between the intensity scattered by the wet sample, I wet (q), and the dry sample, I dry (q), is equal to 0.28 with d carbon ) 2 g/cm 3 and using the value of the liquid density for benzene (the same value is obtained for m-xylene). The dash-dotted curve plotted in Figure 7, overlapping I dry (q) in the middle of the q domain, corresponds to a shift F exp equal to 4.2, that is, C exp ) 0.24, which is larger than the expected C e .…”

Section: I(q)mentioning

confidence: 94%

“…When calibration of the intensity by means of a standard cannot be made accurately, as in the case of powder samples, a determination of the surface area is generally achieved by using the method of the invariant, eq 7 yielding the extend S v of the carbon-air interface by unit volume of sample (in m 2 /cm 3 ) where φ is the volume fraction of carbon and K is the prefactor in the Porod's law describing scattering coming from the final surface:…”

Section: Saxs/waxs Investigation Of the Dry Samplesmentioning

confidence: 99%

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Surface Area and Microporosity of Carbon Aerogels from Gas Adsorption and Small- and Wide-Angle X-ray Scattering Measurements

et al. 2006

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A carbon aerogel was obtained by carbonization of an organic aerogel prepared by sol-gel polymerization of resorcinol and formaldehyde in water. The carbon aerogel was then CO 2 activated at 800°C to increase its surface area and widen its microporosity. Evolution of these parameters was followed by gas adsorption and small-and wide-angle X-ray scattering (SAXS and WAXS, respectively) with contrast variation by using dry and wet (immersion in benzene and m-xylene) samples. For the original carbon aerogel, the surface area, S SAXS , obtained by SAXS, is larger than that obtained by gas adsorption (S ads ). The values become nearly the same as the degree of activation of the carbon aerogel increases. This feature is due to the widening of the narrow microporosity in the carbon aerogel as the degree of activation is increased. In addition, WAXS results show that the short-range spatial correlations into the assemblies of hydrocarbon molecules confined inside the micropores are different from those existing in the liquid phase.

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Section: I(q)mentioning

confidence: 94%

Section: Saxs/waxs Investigation Of the Dry Samplesmentioning

confidence: 99%

Surface Area and Microporosity of Carbon Aerogels from Gas Adsorption and Small- and Wide-Angle X-ray Scattering Measurements

et al. 2006

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“…Recent efforts have focused on the modification of carbon gels through the use of different metal dopants [9][10][11][12][13][14][15][16]. It is worth mentioning that various metals can be easily incorporated into carbon gels to create carbon-metal composites.…”

Section: Introductionmentioning

confidence: 99%

“…Various metal-doped carbon gels have already been prepared and characterized from the point of view of physicochemical properties [17][18][19][20][21]. Metal-doped carbon materials are attractive for several applications, for example in electrochemistry [9,14,[22][23][24] or catalysis [25][26][27][28], but the pores of carbon gels obtained by drying in ambient conditions are often closed, the chemical and electrochemical activity can not be fully utilized. Therefore, activation processes for the composites should be carried out, leading to the modification of the structural surface and resulting in an increase in the volume of open pores, allowing unconstrained diffusion of ions into their interior, and consequently, increasing their activity.…”

Section: Introductionmentioning

confidence: 99%

The effect of catalyst and heat treatment on the properties of carbon–metal composites

Osińska

2015

J Porous Mater

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Carbon gel and carbon-nickel-palladium doped gels (C-Ni-Pd) were prepared by carbonising resorcinol-formaldehyde (RF) hydrogel and resorcinolformaldehyde-nickel-palladium (RF-Ni-Pd) hydrogels at 900°C in a nitrogen atmosphere. RF and RF-Ni-Pd hydrogels were synthesized through sol-gel polycondensation followed by ambient drying. The aim of this study was the determination of the effect of heat treatment in air at 450°C on the properties of C-Ni-Pd gels prepared using different Pd salts. In the present work, Ni was added as acetate whereas Pd was added as acetate (CA-Ni-Pd) and as chloride (CB-Ni-Pd). Samples were examined by scanning electron microscopy and X-ray diffraction. Surface area was characterized by N 2 adsorption at -195.5°C. Thermogravimetric analysis was carried out in order to determine the thermal characteristics of carbon gel and nickel-palladium composites in air atmosphere. CANi-Pd composite had a higher activity and two-phase reaction compared to the CB-Ni-Pd composite. Further improvement of the electrolyte diffusion into the particles of nickel and palladium was obtained by oxidative thermal treatment. During this process a structural modification of the material took place, consequently leading to changes in the electrochemical properties of the composites.

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“…Metal-doped carbon materials are attractive for several applications, for example in electrochemistry [15][16][17][18][19] or catalysis [20][21][22]. To expand their potential applications, recent studies have focused on the modification of carbon gels through the use of doped molecules.…”

Section: Introductionmentioning

confidence: 99%

The influence of thermal treatment on the electrochemical properties of carbon–Ni–Pd composites

Skowroński

Osińska

2014

J Sol-Gel Sci Technol

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Resorcinol-formaldehyde (RF) hydrogel and RF-nickel-palladium (RF-Ni-Pd) hydrogel were synthesized by sol-gel polycondensation followed by ambient drying. Carbon gel and carbon-nickel-palladium doped gels were prepared by carbonizing the RF and RF-Ni-Pd gels at 900°C under a nitrogen atmosphere. The goal of this study was to determine the effect of oxidative thermal treatment on the electrochemical activity of nickel-palladium doped carbon gels (C-Ni-Pd). The scanning electron microscopy analysis, adsorption and X-ray diffraction measurements showed that the admixture of Ni and Pd to carbon matrix resulted in the modification of morphological, porous and crystalline features. It has been demonstrated that composite C-Ni-Pd composed of sphere-like granules incrusted with well-crystalline nickel and palladium particles exhibits electrochemical activity in 6 M KOH aqueous solution. Thermal treatment of the composite carried out in air at 450°C brought about the improvement of electrochemical activity in the potential range of the hydrogen sorption/desorption reaction.

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Structure and electrochemical properties of carbon aerogels polymerized in the presence of Cu2+

Cited by 54 publications

References 29 publications

Surface Area and Microporosity of Carbon Aerogels from Gas Adsorption and Small- and Wide-Angle X-ray Scattering Measurements

Surface Area and Microporosity of Carbon Aerogels from Gas Adsorption and Small- and Wide-Angle X-ray Scattering Measurements

The effect of catalyst and heat treatment on the properties of carbon–metal composites

The influence of thermal treatment on the electrochemical properties of carbon–Ni–Pd composites

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