Carbon Structures Grown by Direct Current Microplasma: Diamonds, Single-Wall Nanotubes, and Graphene

Ghezzi, F.; Cacciamani, G.; Caniello, R.; Toncu, Dana Cristina; Causa, F.; Dellasega, David; Russo, Valeria; Passoni, M.

doi:10.1021/jp501440b

Cited by 11 publications

(8 citation statements)

References 40 publications

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“…In the microwave-activated plasma, the H 2 molecule could be converted to atomic hydrogen (H*). , The energetic H* atoms could displace carbon atoms in both graphite and diamond. Because the displacement energy of graphite is smaller than that of diamond, the reactive H* etches the graphite phase twenty times as fast as it etches diamond. − Therefore, energetic H* atoms could work as an effective “chemical pump” to transform sp 2 -bonded carbon derived from CNWs to sp 3 -bonded carbon in the diamond. , First, the atomic H* could not only add to vacant surface carbon sites and passivate them but also abstract the hydrogen from the surface −C–H sites on the thin hydrogen-terminated diamond nanoplatelets and create reactive surface carbon sites . Because of the dynamic interaction between atomic H* and the surface, the reactive carbon sites would remain at a steady-state concentration .…”

Section: Discussionmentioning

confidence: 99%

“…In the microwave-activated plasma, the H 2 molecule could be converted to atomic hydrogen (H*). 41,42 The energetic H* atoms could displace carbon atoms in both graphite and diamond. Because the displacement energy of graphite is smaller than that of diamond, 43 the reactive H* etches the graphite phase twenty times as fast as it etches diamond.…”

Section: Conversion Mechanism From the Hybrid C/dmentioning

confidence: 99%

“…44−46 Therefore, energetic H* atoms could work as an effective "chemical pump" to transform sp 2 -bonded carbon derived from CNWs to sp 3 -bonded carbon in the diamond. 42,47 First, the atomic H* could not only add to vacant surface carbon sites and passivate them but also abstract the hydrogen from the surface −C−H sites on the thin hydrogen-terminated diamond nanoplatelets and create reactive surface carbon sites. 44 Because of the dynamic interaction between atomic H* and the surface, the reactive carbon sites would remain at a steady-state concentration.…”

Section: Conversion Mechanism From the Hybrid C/dmentioning

confidence: 99%

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In Situ Construction of Hierarchical Diamond Supported on Carbon Nanowalls/Diamond for Enhanced Electron Field Emission

Zhai

Huang

Yang

et al. 2020

ACS Appl. Mater. Interfaces

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The integration of sp2-/sp3-bonded carbon has aroused increasing attention on attaining a great electron field emission (EFE) performance. Herein, a novel hierarchical diamond@carbon nanowalls/diamond (D@C/D) architecture is facilely prepared through the growth of the hybrid carbon nanowalls/diamond (C/D) film followed by the in situ hydrogen plasma treatment using microwave plasma chemical vapor deposition. The hierarchical D@C/D architecture is composed of thin diamond nanoplatelets sandwiched into carbon nanowalls (CNWs) as the bottom layer and the thickened nanoplatelets constituted by diamond nanograins as the upper layer. The hydrogen plasma plays an effective role in the transformation of sacrificial sp2-bonded CNWs to sp3-bonded diamond, eventually leading to the template thickening of diamond nanoplatelets in the upper layer. Impressively, the D@C/D-90 film demonstrates much better EFE behaviors of low turn-on potential (E o = 4.3 V μm–1), high current density (J e@8 V μm–1 = 20.81 mA cm–1), and superior long-term stability, in comparison with the pristine C/D film (E o = 6 V μm–1, J e@8 V μm–1 = 0.33 mA cm–1). The enhanced EFE performance of the hierarchical D@C/D film is ascribed to the well-established graphite pathway for electrons transported from the bottom to the top and the increased diamond emitting sites with negative electron-affinity and robust nature at the top. This work will promote the development of the high-performance cathode EFE material based on hybrid sp2/sp3-bonded carbon, and the method proposed here also provides an effective strategy to construct a diamond nanostructure for various applications.

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Section: Discussionmentioning

confidence: 99%

Section: Conversion Mechanism From the Hybrid C/dmentioning

confidence: 99%

Section: Conversion Mechanism From the Hybrid C/dmentioning

confidence: 99%

See 1 more Smart Citation

In Situ Construction of Hierarchical Diamond Supported on Carbon Nanowalls/Diamond for Enhanced Electron Field Emission

Zhai

Huang

Yang

et al. 2020

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

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“…The generated gas discharges contain a high density of energetic electrons (>10 eV) that allows efficient material synthesis and processing. The previous reports also have demonstrated the feasibility of the microplasma-based process to produce metal ( Chiang & Sankaran, 2009 ; Chiang & Sankaran, 2008 ) and semiconductor nanoparticles ( Sankaran et al, 2005 ), oxides ( Mariotti, Bose & Ostrikov, 2009 ), and carbon nanostructures ( Ghezzi et al, 2014 ; Luo et al, 2016 ).…”

Section: Introductionmentioning

confidence: 96%

Microplasma-assisted hydrogel fabrication: A novel method for gelatin-graphene oxide nano composite hydrogel synthesis for biomedical application

Satapathy

Chiang

Chuang

et al. 2017

PeerJ

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Toxicity issues and biocompatibility concerns with traditional classical chemical cross-linking processes prevent them from being universal approaches for hydrogel fabrication for tissue engineering. Physical cross-linking methods are non-toxic and widely used to obtain cross-linked polymers in a tunable manner. Therefore, in the current study, argon micro-plasma was introduced as a neutral energy source for cross-linking in fabrication of the desired gelatin-graphene oxide (gel-GO) nanocomposite hydrogel scaffolds. Argon microplasma was used to treat purified gelatin (8% w/v) containing 0.1∼1 wt% of high-functionality nano-graphene oxide (GO). Optimized plasma conditions (2,500 V and 8.7 mA) for 15 min with a gas flow rate of 100 standard cm3/min was found to be most suitable for producing the gel-GO nanocomposite hydrogels. The developed hydrogel was characterized by the degree of cross-linking, FTIR spectroscopy, SEM, confocal microscopy, swelling behavior, contact angle measurement, and rheology. The cell viability was examined by an MTT assay and a live/dead assay. The pore size of the hydrogel was found to be 287 ± 27 µm with a contact angle of 78° ± 3.7°. Rheological data revealed improved storage as well as a loss modulus of up to 50% with tunable viscoelasticity, gel strength, and mechanical properties at 37 °C temperature in the microplasma-treated groups. The swelling behavior demonstrated a better water-holding capacity of the gel-GO hydrogels for cell growth and proliferation. Results of the MTT assay, microscopy, and live/dead assay exhibited better cell viability at 1% (w/w) of high-functionality GO in gelatin. The highlight of the present study is the first successful attempt of microplasma-assisted gelatin-GO nano composite hydrogel fabrication that offers great promise and optimism for further biomedical tissue engineering applications.

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“…The Chemical Vapor Deposition (CVD) method [9] allows one to obtain diamonds by depositing carbon on an initial diamond plate in a hydrogen-methane-based plasma. There are three main ways to create plasma in CVD reactors-hot filament [10], direct current [11], and microwave-referred to as HF-, DC-, and M-CVD [12,13]. Generally, M-CVD demands less electric power to grow single-crystal diamonds, and we have therefore used it in this study as a low-rate energy benchmark for all CVD sub-methods.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Analysis of Energy and Water Consumption of Mined versus Synthetic Diamonds

et al. 2021

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In our research, we analyzed the energy and water consumption in diamond mining and laboratory synthesis operations. We used publicly available reports issued by two market leaders, DeBeers and ALROSA, to estimate water and energy use per carat of a rough diamond. The efficiency of the two most popular synthesis technologies for artificial diamonds—High-Pressure-High-Temperature (HPHT) and Microwave-assisted Chemical Vapor Deposition (M-CVD)—was examined. We found that the modern HPHT presses, with open cooling circuits, consume about 36 kWh/ct when producing gem-quality and average-sized (near-) colorless diamonds. ALROSA and DeBeers use about 96 kWh/ct and 150 kWh/ct, respectively, including all energy required to mine. Energy consumption of M-CVD processes can be different and depends on technological conditions. Our M-CVD machine is the least energy-efficient, requiring about 215 kWh/ct in the single-crystal regime, using 2.45-GHz magnetron for the support synthesis. The M-CVD methods of individual synthetic companies IIa Technology and Ekati Mine are different from our results and equal 77 and 143 kWh/ct, respectively. Water consumption for the HPHT and M-CVD methods was insignificant: approximately zero and 0.002 m3/ct, respectively, and below 0.077 m3/ct for ALROSA-mined diamonds. This study touches upon the impact of the diamond production methods used on the carbon footprint.

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Carbon Structures Grown by Direct Current Microplasma: Diamonds, Single-Wall Nanotubes, and Graphene

Cited by 11 publications

References 40 publications

In Situ Construction of Hierarchical Diamond Supported on Carbon Nanowalls/Diamond for Enhanced Electron Field Emission

In Situ Construction of Hierarchical Diamond Supported on Carbon Nanowalls/Diamond for Enhanced Electron Field Emission

Microplasma-assisted hydrogel fabrication: A novel method for gelatin-graphene oxide nano composite hydrogel synthesis for biomedical application

A Comparative Analysis of Energy and Water Consumption of Mined versus Synthetic Diamonds

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