The effect of reduced graphene oxide addition on the superconductivity of MgB2

Silva, K S. B De; Gambhir, Sanjeev; Wang, Xiaolin; Xu, Xiaojing; Li, W X; Officer, David L.; Wexler, David; Wallace, Gordon G.; Dou, Shi Xue

doi:10.1039/c2jm30323j

Cited by 45 publications

(46 citation statements)

References 30 publications

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“…It is seen in Figure 2 that at annealing temperature of 500 o C the TiO2 are completely in rutile phase. The main peak is corresponding to the diffraction phase of [10] surface of rutile TiO2 at 27.4 o C. Peak of reduced graphene oxide occurs and corresponds to 2 = 25.0 o C which is similar to the works in [13][14][15]. A strong peak of graphite is still remaining at 2 = 26.1 o C. The electrical conductivity of rGO sample 1.89 Scm -1 is much higher than the conductivity of pure graphite used in this work, about 0.18 Scm -1…”

Section: Resultssupporting

confidence: 56%

Transmission characteristic of graphene/TiO2 paper measured at Ka-band

Agusu¹,

Mitsudo²,

Ahmad³

et al. 2017

AIP Conference Proceedings

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Section: Resultssupporting

confidence: 56%

Transmission characteristic of graphene/TiO2 paper measured at Ka-band

Agusu¹,

Mitsudo²,

Ahmad³

et al. 2017

AIP Conference Proceedings

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“…GO-MWCNT dispersions were characterized by X-ray photoelectron spectroscopy (XPS) before and after hydrazine reduction to quantify the ratio of carbon to oxygen containing groups in the final dispersion. It is evident in Figure 1(a) and (b) that there is a significant decrease in C-O content (286 eV) relative to the C=C/C-C peak (284 eV) after chemical reduction of a GO dispersion [45][46]. This shows the extent of oxygen defects removed from the GO sheets that contribute to the number of sp 2 bonded carbon sites, directly affecting the electrical resistivity of the material [47] [48].…”

Section: Dispersion and Electrode Propertiesmentioning

confidence: 99%

Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance

Grosse

Champavert

Gambhir

et al. 2013

Carbon

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(2013). Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance. Carbon, 61 (September), 467-475. Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance AbstractAqueous dispersions of reduced graphene oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilising compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are maintained. In this study, rGO acts as an effective dispersing agent for MWCNTs and does not affect the solubility or electroactivity of the GOx. Bioelectrodes fabricated from these rGO-MWCNT-GOx dispersions were characterised electrochemically to test their feasibility in facilitating direct electron transfer (DET) from the redox centre of the enzyme to the electrode. The DET results showed that the specific catalytic current generated at an optimised rGO-MWCNT-GOx electrode was 72 uA/ug which is 144 times more efficient than other literature values for similar systems. The remarkable specific catalytic current can be attributed to the use of purified enzyme, the efficiency of charge transfer within the rGO-MWCNT composite and the ability of the electrode to facilitate direct electron transfer. Abstract:Aqueous dispersions of reduced Graphene Oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilizing compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are maintained. In this study, rGO acts as an effective dispersing agent for MWCNTs and does not affect the solubility or electroactivity of the GOx.Bioelectrodes fabricated from these rGO-MWCNT-GOx dispersions were characterised electrochemically to test their feasibility in facilitating direct electron transfer (DET) from the redox centre of the enzyme to the electrode. The DET results showed that the specific catalytic current generated at an optimized rGO-MWCNT-GOx electrode was 72 µA/µg GOx, which is 144 times m...

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“…In addition to this, carbon doping also introduces defects in the sample, which act as pinning centers, leading to improvements in J c (H) and H irr [20]. Recently, the effect of graphene doping on the superconducting properties of MgB 2 has been investigated [21][22][23] [23]. Thus, these recent reports show that graphene doping in MgB 2 provides efficient flux pinning, leading to improvements in J c , and suggest a further detailed investigation on graphene-doped MgB 2 using a wider range of compositions of graphene would help to understand the pinning mechanism and effects of doping on superconducting properties such as T c , H c2 and H irr .…”

Section: Introductionmentioning

confidence: 99%

Effect of graphene oxide doping on superconducting properties of bulk MgB₂

Sudesh

Kumar

Das

et al. 2013

Supercond. Sci. Technol.

319

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In the present paper we report the effect of graphene oxide (GO) doping on the structural and superconducting properties of MgB 2 . Bulk polycrystalline samples have been synthesized via a solid state reaction route with compositions MgB 2 + x wt% of GO (x = 0, 1, 2, 3, 5, 7 and 10) by sintering at ∼850 • C in a reducing atmosphere of Ar/H 2 (9:1). The x-ray diffraction results confirm the formation of the MgB 2 phase in all samples, together with traces of a MgO impurity phase. The XRD data results also show substitution of carbon for boron, but in the present case the actual amount of carbon substituting for boron is very small as compared to other carbon sources. A substantial improvement in the critical current density, J c (H), has been observed in the entire magnetic field range (0-8 T) for samples x = 1, 2 and 3 as compared to the undoped sample. In addition to J c (H), marginal improvements in the upper critical field (H c2 ) and the irreversibility field (H irr ) have been observed for the doped samples x = 1, 2 and 3 with respect to pristine MgB 2 . Furthermore, a curious result of the present investigation is that there is no change in the superconducting transition temperature (T c ) up to a doping level of 10 wt%. The possible mechanisms of flux pinning and correlations between the observed superconducting properties and structural characteristics of the samples have been described and discussed in this paper.

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The effect of reduced graphene oxide addition on the superconductivity of MgB2

Cited by 45 publications

References 30 publications

Transmission characteristic of graphene/TiO2 paper measured at Ka-band

Transmission characteristic of graphene/TiO2 paper measured at Ka-band

Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance

Effect of graphene oxide doping on superconducting properties of bulk MgB₂

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The effect of reduced graphene oxide addition on the superconductivity of MgB2

Cited by 45 publications

References 30 publications

Transmission characteristic of graphene/TiO2 paper measured at Ka-band

Transmission characteristic of graphene/TiO2 paper measured at Ka-band

Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance

Effect of graphene oxide doping on superconducting properties of bulk MgB2

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Effect of graphene oxide doping on superconducting properties of bulk MgB₂