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Palmer, Richard A.; Doan, Thanh-Hoa; Lloyd, P.G.; Jarvis, B.L.; Ahmed, Nazia

doi:10.1023/a:1015378931111

Cited by 36 publications

(7 citation statements)

References 7 publications

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“…TiO 2 can be easily reduced to Ti by appropriate treatment under hydrogen plasma , and a hydrogen atmosphere. , Therefore, to study graphene synthesis on Ti, TiO 2 was reduced to Ti under a hydrogen atmosphere before initiating graphene synthesis. The CVD system consisted of a two heating zone for reduction of TiO 2 to Ti.…”

Section: Methodsmentioning

confidence: 99%

Defect-Free Graphene Synthesized Directly at 150 °C via Chemical Vapor Deposition with No Transfer

et al. 2018

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Direct graphene synthesis on substrates via chemical vapor deposition (CVD) is an attractive approach for manufacturing flexible electronic devices. The temperature for graphene synthesis must be below ∼200 °C to prevent substrate deformation while fabricating flexible devices on plastic substrates. Herein, we report a process whereby defect-free graphene is directly synthesized on a variety of substrates via the introduction of an ultrathin Ti catalytic layer, due to the strong affinity of Ti to carbon. Ti with a thickness of 10 nm was naturally oxidized by exposure to air before and after the graphene synthesis, and the various functions of neither the substrates nor the graphene were influenced. This report offers experimental evidence of high-quality graphene synthesis on Ti-coated substrates at 150 °C via CVD. The proposed methodology was applied to the fabrication of flexible and transparent thin-film capacitors with top electrodes of high-quality graphene.

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Section: Methodsmentioning

confidence: 99%

Defect-Free Graphene Synthesized Directly at 150 °C via Chemical Vapor Deposition with No Transfer

et al. 2018

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“…49 Unlike CuO, the reduction of TiO 2 , our passive film here, by H is not so easy; it requires special conditions of hydrogen discharge and temperature. [52][53][54] For example, Zhang et al 53 reduced some oxidized Ti coupons under a hydrogen discharge in a reaction tube with a constant, 100% hydrogen flow of 1L/min. The discharge was created by two pure tungsten electrodes connected to a spark generator, which supplied sparks of 12 kV at 8 A with approximately 0.3 J per spark, at rates up to 200 Hz.…”

Section: Morphologies and Compositions Of The Ti-aunps Modifiedmentioning

confidence: 99%

Activation of Titanium for Synthesis of Supported and Unsupported Metallic Nanoparticles

Amin

Fadlallah

Alosaimi

2014

J. Electrochem. Soc.

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Titanium (Ti) resists corrosion due to spontaneous passivation and subsequent formation of a stable, substantially inert oxide film. This passive film limits the reducing ability of Ti in wet chemical synthesis. Aggressive anions are applied here to destabilize Ti passivity, with the objective of activating Ti as a reducing agent for wet-chemical synthesis, through the formation of unsupported and supported metallic nanoparticles (MNPs). For instance, within the first minute of Ti immersion in a standard gold solution (SGS), 1000 ± 3 μg Au/mL in 2% HCl, gold nanoparticles (AuNPs) in solution (unsupported) and a considerable population of highly dispersed AuNPs on Ti (Ti-supported AuNPs) are obtained. This occurs at room temperature, without using reducing agents, stabilizers, or any chemical pre-treatments. Electrochemical measurements revealed that the passivity of Ti was destabilized (oxide thinning/dissolution) in the SGS. The addition of F − to the SGS promoted destabilization of the passive film, and hence activated the reducing ability of Ti. This in turn resulted in significant increase in the population of AuNPs on Ti. Reduction of cations in solution by the active nascent (atomic) hydrogen (H) generated by substrate (Ti) dissolution, promoted by the addition of F − , in acidic medium is confirmed here and discussed vs. conductivity of the oxide (passive) film and solution pH. Experimental findings reveal that the relevance of H as the actual reducing agent is limited to instantaneous and non-conductive passive films. Solution pH studies on such passive films show that the Nernst equation (dE H/H + /d(pH) = −0.059 V) controls the wet chemical synthesis of MNPs rather than E o reduction of the base metal (the substrate). Based on polarization measurements, the prepared Ti-supported AuNPs are demonstrated here as highly active electrocatalysts (better than Pt) for the hydrogen evolution reaction (HER) in 0.1 M HCl solution.Nanoparticles constitute a key area of research and development in the burgeoning field of nanotechnology. The attraction of nanoparticles lies in the myriad of attractive characteristics which can be achieved by reducing suitable materials from the bulk to the nanometer size, these characteristics ranging from increased surface/volume ratio to novel quantum confinement effects. 1 Examples of property enhancements include magnetic, optical, biosensing, thermoelectric, semiconducting, catalytic, energy storage and thermal properties. 2-7 An interesting aspect of nanoparticles is the wide range of material classes in which nanoparticles are useful, including semiconductor, dielectric, metallic, ceramic, composite and polymer nanoparticles. For these reasons, metal nanoparticles have attracted a high interest in scientific research and industrial applications. [8][9][10] Metal nanoparticles (MNPs) can be produced by reducing metal salts with reducing agents and stabilizing them with capping ligands, 11 and they can be subsequently attached to another metal. However, it is more desirable to d...

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“…In the process of thermal spraying, the molten TiO 2 particles caused lattice anoxia in the high-temperature flame flow under low oxygen partial pressure [26]. In addition, hydrogen plasma has a strong reduction effect on TiO 2 , promoting the formation of anoxic phase in the coating during the spraying process [27]. Diffraction peaks of MgAl 2 O 4 could be detected in both coatings and powders, but no peaks of other phases of Mg and Al elements.…”

Section: Performance Characterization Of Coatingsmentioning

confidence: 97%

Property of TiO2-15MgAl2O4 Electrical-Heating Coating Prepared by Atmospheric Plasma Spraying and Hydrogen Heat Treatment

Yang

Wang

et al. 2020

Coatings

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Using TiO 2 -15MgAl 2 O 4 mixed powder as spray-feed, an electrical-heating coating was successfully fabricated by atmospheric plasma spraying technology. The phase composition, microstructure, and electrical-heating performance of the coating were characterized by XRD, SEM, and cyclic electrification tests, respectively. The coating samples were heat-treated at 350 • C in a hydrogen atmosphere. The results show that TiO 2 -15MgAl 2 O 4 coating can be heated over 300 • C within 30 m at 55.1 V which preserves heat for a long time. Before heat treatment, the available heating temperature of the coating decreases significantly with electrification cycles. The resistivity of coating rises rapidly during the cyclic electricity test. After hydrogen heat treatment, the electrical-heating property of coatings is significantly enhanced.

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Untitled

Cited by 36 publications

References 7 publications

Defect-Free Graphene Synthesized Directly at 150 °C via Chemical Vapor Deposition with No Transfer

Defect-Free Graphene Synthesized Directly at 150 °C via Chemical Vapor Deposition with No Transfer

Activation of Titanium for Synthesis of Supported and Unsupported Metallic Nanoparticles

Property of TiO2-15MgAl2O4 Electrical-Heating Coating Prepared by Atmospheric Plasma Spraying and Hydrogen Heat Treatment

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