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Carbide

About: Carbide is a research topic. Over the lifetime, 36331 publications have been published within this topic receiving 503586 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, high temperature gas sensors based on catalytic metal-insulator-silicon carbide (MISiC) devices are developed both as capacitors and Schottky diodes.
Abstract: High temperature gas sensors based on catalytic metal-insulator-silicon carbide (MISiC) devices are developed both as capacitors and Schottky diodes. A maximum operation temperature of 1000 degrees C is obtained for capacitors based on 4H-SiC, and all sensors work routinely for several weeks at 600 degrees C. Reducing gases like hydrocarbons and hydrogen lower the flat band voltage of the capacitor and the barrier height of the diode. The time constants for the gas response are in the order of milliseconds and because of this good performance the sensors are tested for combustion engine control. For temperatures around 600 degrees C total combustion occurs on the sensor surface and the signal is high for fuel in excess and low for air in excess. At temperatures around 400 degrees C the response is more linear. The high temperature operation causes interdiffusion of the metal and insulator layers in these devices; and this interdiffusion has been studied. At sufficiently high temperatures the inversion capacitance shows different levels for hydrogen free and hydrogen containing ambients, which is suggested to be due to a reversible hydrogen annealing effect at the insulator-silicon carbide interface.

168 citations

Patent
18 Mar 2008
TL;DR: A carbon nanotube hybrid system is a mixture of a carbide compound and a halogen group containing gas to extract elements of the carbide compounds except carbons.
Abstract: A carbon nanotube hybrid system includes: a carbide-derived carbon prepared by reacting a carbide compound and a halogen group containing gas to extract elements of the carbide compound except carbons; metals supported on the carbide-derived carbon or remaining in the carbide-derived carbon; and carbon sources from which carbon nanotubes are grown from the carbide-derived carbon A method of preparing the carbon nanotube hybrid system includes preparing the carbide-derived carbon, extracting elements therefrom, and growing carbon nanotubes from the carbide-derived carbon The carbon nanotube hybrid system has excellent uniformity and a long lifetime An electron emitter having improved electron emitting properties can be inexpensively prepared using the carbon nanotube hybrid system compared to conventional carbon nanotubes An electron emission device having excellent electron emitting properties can be prepared using the electron emitter

168 citations

Journal ArticleDOI
TL;DR: In this article, the authors reviewed the latest research progress on the molybdenum carbide catalyst for hydrogen production and concluded that solid-solid reaction method could provide high surface area and the synthesis process is relatively easy and safe.
Abstract: Hydrogen energy has become an important research area worldwide for environmental-friendly and sustainable energy development. A large number of studies can be found in the literature regarding the development of novel functional catalysts for hydrogen production from various reactions such as hydrocarbon reforming, water gas shift reaction, and water decomposition reaction. Due to the unique surface and electronic properties of molybdenum carbide, it has been attracted more and more attentions as a potential catalyst. This article reviews the latest research progress on the molybdenum carbide catalyst for hydrogen production. Two main parts are included in this review: preparation of molybdenum carbide and application of it in hydrogen production technology. In the first part, various molybdenum carbide preparation methods and the strategies to modify the physicochemical properties of molybdenum carbide are described. It is concluded that solid-solid reaction method could provide high surface area and the synthesis process is relatively easy and safe. Furthermore, the addition of second metal could increase molybdenum carbide surface area and adjust catalyst surface electronic condition. In the second part, the applications of molybdenum carbide based catalysts for various reactions for hydrogen production are described. The catalytic activity, stability, and deactivation and reaction mechanism over molybdenum carbide catalyst are critically reviewed and discussed. It indicates that molybdenum carbide should be an alternative catalyst with high efficiency for hydrogen production.

168 citations

Journal ArticleDOI
TL;DR: In this paper, a simple and direct pyrolysis method using melamine and ferric chloride as the C, N and Fe precursors was used to synthesize Fe3C@NCNT.
Abstract: Nitrogen-doped carbon nanotubes encapsulating iron carbide (Fe3C) nanocrystals (Fe3C@NCNT) were fabricated by a simple and direct pyrolysis method using melamine and ferric chloride as the C, N and Fe precursors. The surface morphology, structure and composition of the Fe3C@NCNT materials were thoroughly investigated. The nanomaterials were employed as novel catalysts for peroxymonosulfate (PMS) activation; outstanding efficiency, high stability and excellent reusability were observed in the catalytic oxidation of organics. The encapsulated Fe3C nanoparticles played a key role in the emerging synergetic effects of the carbide and the protective graphitic layers. In addition, the quaternary N and trace amounts of iron on the CNT surface acted as the active sites. Various quenching experiments were carried out to elucidate the catalytic mechanism of Fe3C@NCNT. It was found that singlet oxygen, superoxide, sulfate and hydroxyl radicals worked together to degrade phenol solutions. Due to their simple synthesis method, low-cost precursors, unique structure and excellent catalytic activity and stability, these novel iron-carbide-based composites have great potential as new strategic materials for environmental catalysis.

168 citations

Journal ArticleDOI
TL;DR: In this paper, a new type of boron-carbon polymer is proposed to serve as a precursor for the synthesis of B 4 C. The polymeric precursor is synthesized by the reaction of boric acid and polyvinyl alcohol that after pyrolysis at 400°C and 800°C gives B 4C.
Abstract: Boron carbide is one of the hardest materials with diamond-like mechanical properties, and is already used for a variety of applications including armor plating, blasting nozzles, and mechanical seal faces, as well as for grinding and cutting tools. It is produced on an industrial scale by classical carbothermal reduction of boric oxides at high temperatures, but the formation of pure boron carbide in processed forms, such as films and fibers, is difficult. As an alternative to high-temperature powder techniques, there is recently great interest in the development of polymer precursors to produce ceramic materials. The aim of the present work is to develop a cost effective and low-temperature manufacturing process to synthesize boron carbide from cheap and easily available raw materials. The initial objective of our research is the design and synthesis of a new type of boron–carbon polymer, which would serve as precursor for boron carbide. The polymeric precursor is synthesized by the reaction of boric acid and polyvinyl alcohol that after pyrolysis at 400 °C and 800 °C gives boron carbide. The polymeric precursor and its pyrolyzed products are characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). X-ray diffraction shows that boron carbide (B 4 C) obtained from this method has an orthorhombic crystal structure. It is a unique low-temperature (∼400 °C) synthetic route for boron carbide.

168 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,218
20222,462
2021994
20201,277
20191,413
20181,471