Thermal decomposition and structural variation by heating on hydrogenated amorphous carbon films

Akasaka, Hiroki; Tunmee, Sarayut; Rittihong, Ukit; Tomidokoro, Masashi; Euaruksakul, Chanan; Norizuki, Souta; Supruangnet, Ratchadaporn; Nakajima, Hideki; Hirata, Yuki; Ohtake, Naoto

doi:10.1016/j.diamond.2019.107609

Cited by 8 publications

(5 citation statements)

References 23 publications

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“…The near-edge X-ray absorption fine structure spectroscopy (NEXAFS) was measured at BL3.2 of the Synchrotron Light Research Institute (SLRI), Thailand. The K-edge NEXAFS spectra of carbon, oxygen, and nitrogen were obtained using an energy resolution of 0.5 eV (fwhm) in the total electron yield (TEY) mode. , The C K edge spectra were normalized with standard gold and calibrated with highly ordered pyrolytic graphite (HOPG) at 291.65 eV.…”

Section: Methodsmentioning

confidence: 99%

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Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H₂O₂ from O₂ Reduction

Chakthranont

Nitrathorn

Thongratkaew

et al. 2021

ACS Appl. Energy Mater.

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Electroreduction of O2 is a promising method for decentralized H2O2 production. Due to their high selectivity, low cost, and highly tunable properties, O- and N-doped carbon catalysts are appealing for this process. However, the relative effects of O and N dopants on the catalytic performances of carbon are not well understood. In this work, we present highly active and selective 2e– O2 reduction catalysts based on doped carbon nanohorns (CNH) synthesized by the gas-injected arc-in-water (GI-AIW) method. The effects of O and N dopants incorporated during the synthesis and the post-treatment are investigated. We discovered that the selectivity of CNH may be more sensitive to changes in N dopant than to changes in O dopant. Our doped CNH catalyst exhibits an early onset potential of 0.85 V vs RHE, >80% selectivity, and excellent stability even after 5,000 cycles and 12 h of flow electrolysis. Our gas diffusion device can generate H2O2 at a practical concentration of 56 mM per hour, corresponding to a production rate of 0.74 mol h–1 gcat –1. These results suggest that regulating both O and N dopants is an effective design strategy for an efficient carbon catalyst, which is essential in the electrosynthesis of H2O2 from O2.

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Section: Methodsmentioning

confidence: 99%

“…The K-edge NEXAFS spectra of carbon, oxygen, and nitrogen were obtained using an energy resolution of 0.5 eV (fwhm) in the total electron yield (TEY) mode. 37,38 The C K edge spectra were normalized with standard gold and calibrated with highly ordered pyrolytic graphite (HOPG) at 291.65 eV.…”

Section: ■ Introductionmentioning

confidence: 99%

Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H₂O₂ from O₂ Reduction

Chakthranont

Nitrathorn

Thongratkaew

et al. 2021

ACS Appl. Energy Mater.

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“…6 Typical mass spectra of alkene and alkane generated from the DLC film heated to 400 °C obtained by TDS-GC/MS and alkanes are shown in Fig. 7 [26,27]. However, these studies did not obtain hydrocarbons with carbon numbers larger than that of hexane (C 8 H 16 ), which were observed in this study.…”

Section: Tds-gc/ms Resultsmentioning

confidence: 57%

“…The thermal decomposition of hydrogenated DLC films has only been empirically established, and the corresponding heat resistance is expected to be dependent on the structure of the film. Akasaka et al used thermal desorption spectroscopy (TDS) with QMS to confirm that the hydrocarbons were decomposed into C 2 H 4 and C 3 H 8 [26,27]. Ristein et al performed a comparative analysis of quantitative infrared absorption spectra and mass-selected thermal effusion transients for a large number of hydrogenated amorphous carbon films [28].…”

Section: Introductionmentioning

confidence: 99%

Low Friction of Diamond-Like Carbon Film Due to Liquid Hydrocarbon Generated by Laser Heating in a Nitrogen Gas Environment

et al. 2020

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In this study, we investigated the low friction mechanism of a diamond-like carbon (DLC) film heated by laser irradiation in a nitrogen gas environment. The friction coefficient decreased from 0.5 to 0.06 when the contact area was heated to 250 °C. Subsequently, we heated the DLC film under non-contact conditions (2 μm distance between DLC film and pin surface) and collected the liquid materials adhered on the pin surface. The adhered materials were revealed to be hydrocarbons with -CH 2 -main-chains, as observed using Raman spectroscopy. On the other hand, thermal desorption gas chromatography with mass spectrometry using helium as a carrier gas demonstrated that hydrocarbons such as alkenes and alkanes with relatively high molecular weight were generated from heated DLC. This agreement between the results of the two analysis techniques suggested that the hydrocarbons in the liquid phase at room temperature were generated from the DLC film heated to a high temperature over 250 °C in an inert gas atmosphere. In addition, we confirmed the reduction in the friction coefficient after pre-heating a different location, as well as the dependence of the friction coefficient on the sliding velocity. The results suggest that hydrocarbons (e.g., alkenes or alkanes) generated upon DLC heating could possibly act as a lubricant to reduce the friction coefficient.

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“…Previously, it has been found that a rapid formation of Pt crystallites start nucleating around 580–650°C [ 47 ] but that, for a different application, weld stability still held up until 890°C [ 48 ]. Also, a study made on amorphous carbon films suggested complete graphitization above 450°C [ 49 ] and some loss of mass due to hydrocarbon desorption if the broken material still contains H [ 50 ] as perhaps hydrocarbon species do appear in the atom probe spectra of decomposed weld material [ 10 ]. This may actually be an issue in a heated hydrogen environment, such as used in both experiments here, which may react with and deplete the amorphous carbon.…”

Section: Discussionmentioning

confidence: 99%

Laser-equipped gas reaction chamber for probing environmentally sensitive materials at near atomic scale

et al. 2022

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Numerous metallurgical and materials science applications depend on quantitative atomic-scale characterizations of environmentally-sensitive materials and their transient states. Studying the effect upon materials subjected to thermochemical treatments in specific gaseous atmospheres is of central importance for specifically studying a material’s resistance to certain oxidative or hydrogen environments. It is also important for investigating catalytic materials, direct reduction of an oxide, particular surface science reactions or nanoparticle fabrication routes. This manuscript realizes such experimental protocols upon a thermochemical reaction chamber called the "Reacthub" and allows for transferring treated materials under cryogenic & ultrahigh vacuum (UHV) workflow conditions for characterisation by either atom probe or scanning Xe+/electron microscopies. Two examples are discussed in the present study. One protocol was in the deuterium gas charging (25 kPa D2 at 200°C) of a high-manganese twinning-induced-plasticity (TWIP) steel and characterization of the ingress and trapping of hydrogen at various features (grain boundaries in particular) in efforts to relate this to the steel’s hydrogen embrittlement susceptibility. Deuterium was successfully detected after gas charging but most contrast originated from the complex ion FeOD+ signal and the feature may be an artefact. The second example considered the direct deuterium reduction (5 kPa D2 at 700°C) of a single crystal wüstite (FeO) sample, demonstrating that under a standard thermochemical treatment causes rapid reduction upon the nanoscale. In each case, further studies are required for complete confidence about these phenomena, but these experiments successfully demonstrate that how an ex-situ thermochemical treatment can be realised that captures environmentally-sensitive transient states that can be analysed by atomic-scale by atom probe microscope.

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Thermal decomposition and structural variation by heating on hydrogenated amorphous carbon films

Cited by 8 publications

References 23 publications

Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H₂O₂ from O₂ Reduction

Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H₂O₂ from O₂ Reduction

Low Friction of Diamond-Like Carbon Film Due to Liquid Hydrocarbon Generated by Laser Heating in a Nitrogen Gas Environment

Laser-equipped gas reaction chamber for probing environmentally sensitive materials at near atomic scale

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Thermal decomposition and structural variation by heating on hydrogenated amorphous carbon films

Cited by 8 publications

References 23 publications

Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H2O2 from O2 Reduction

Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H2O2 from O2 Reduction

Low Friction of Diamond-Like Carbon Film Due to Liquid Hydrocarbon Generated by Laser Heating in a Nitrogen Gas Environment

Laser-equipped gas reaction chamber for probing environmentally sensitive materials at near atomic scale

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Product

Resources

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Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H₂O₂ from O₂ Reduction

Rational Design of Metal-free Doped Carbon Nanohorn Catalysts for Efficient Electrosynthesis of H₂O₂ from O₂ Reduction