The Experts below are selected from a list of 5157 Experts worldwide ranked by ideXlab platform
Xining Zang - One of the best experts on this subject based on the ideXlab platform.
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laser sculptured ultrathin Transition Metal Carbide layers for energy storage and energy harvesting applications
Nature Communications, 2019Co-Authors: Xining Zang, Cuiying Jian, Wanlin Wang, Buxuan Li, Mateo Follmar Diaz, Paul D Ashby, Zhengmao Lu, Zizhao Wang, Xinrui DingAbstract:Ultrathin Transition Metal Carbides with high capacity, high surface area, and high conductivity are a promising family of materials for applications from energy storage to catalysis. However, large-scale, cost-effective, and precursor-free methods to prepare ultrathin Carbides are lacking. Here, we demonstrate a direct pattern method to manufacture ultrathin Carbides (MoCx, WCx, and CoCx) on versatile substrates using a CO2 laser. The laser-sculptured polycrystalline Carbides (macroporous, ~10–20 nm wall thickness, ~10 nm crystallinity) show high energy storage capability, hierarchical porous structure, and higher thermal resilience than MXenes and other laser-ablated carbon materials. A flexible supercapacitor made of MoCx demonstrates a wide temperature range (−50 to 300 °C). Furthermore, the sculptured microstructures endow the Carbide network with enhanced visible light absorption, providing high solar energy harvesting efficiency (~72 %) for steam generation. The laser-based, scalable, resilient, and low-cost manufacturing process presents an approach for construction of Carbides and their subsequent applications. Transition Metal Carbides are attractive for electrochemical energy storage and catalysis, but cost effective preparation on a large scale is challenging. Here the authors use a direct pattern method to fabricate Transition Metal Carbides for supercapacitors and solar energy harvesting for steam generation.
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laser sculptured ultrathin Transition Metal Carbide layers for energy storage and energy harvesting applications
Nature Communications, 2019Co-Authors: Xining Zang, Cuiying Jian, Wanlin Wang, Mateo Follmar Diaz, Paul D Ashby, Taishan Zhu, Zheng Fan, Minsong Wei, Yao ChuAbstract:Ultrathin Transition Metal Carbides with high capacity, high surface area, and high conductivity are a promising family of materials for applications from energy storage to catalysis. However, large-scale, cost-effective, and precursor-free methods to prepare ultrathin Carbides are lacking. Here, we demonstrate a direct pattern method to manufacture ultrathin Carbides (MoCx, WCx, and CoCx) on versatile substrates using a CO2 laser. The laser-sculptured polycrystalline Carbides (macroporous, ~10-20 nm wall thickness, ~10 nm crystallinity) show high energy storage capability, hierarchical porous structure, and higher thermal resilience than MXenes and other laser-ablated carbon materials. A flexible supercapacitor made of MoCx demonstrates a wide temperature range (-50 to 300 °C). Furthermore, the sculptured microstructures endow the Carbide network with enhanced visible light absorption, providing high solar energy harvesting efficiency (~72 %) for steam generation. The laser-based, scalable, resilient, and low-cost manufacturing process presents an approach for construction of Carbides and their subsequent applications.
Michel W. Barsoum - One of the best experts on this subject based on the ideXlab platform.
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Overview of the synthesis of MXenes and other ultrathin 2D Transition Metal Carbides and nitrides
Current Opinion in Solid State and Materials Science, 2019Co-Authors: Louisiane Verger, Varun Natu, Hui-ming Cheng, Wencai Ren, Chuan Xu, Michel W. BarsoumAbstract:In 2011, a new family of two dimensional (2D) Carbides, carbonitrides and nitrides – labeled MXenes – was discovered. Since then the number of papers on these materials has increased exponentially for several reasons amongst them: their hydrophilic nature, excellent electronic conductivities and ease of synthesizing large quantities in water. This unique combination of properties and ease of processing has positioned them as enabling materials for a large, and quite varied, host of applications from energy storage to electromagnetic shielding, transparent conductive electrodes, electrocatalysis, to name a few. Since the initial synthesis of Ti 3 C 2 in hydrofluoric acid, many more compositions were discovered, and different synthesis pathways were explored. Most of the work done so far has been conducted on top-down synthesis where a layered parent compound is etched and then exfoliated. Three bottom-up synthesis methods, chemical vapor deposition, a template method and plasma enhanced pulsed laser deposition have been reported. The latter methods enable the synthesis of not only high-quality ultrathin 2D Transition Metal Carbide and nitride films, but also those that could not be synthesized by selective etching. This article reviews and summarizes the most important breakthroughs in the synthesis of MXenes and high-quality ultrathin 2D Transition Metal Carbide and nitride films.
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porous two dimensional Transition Metal Carbide mxene flakes for high performance li ion storage
ChemElectroChem, 2016Co-Authors: Chang E Ren, Sankalp Kota, Joseph Halim, Taron Makaryan, Babak Anasori, Mengqiang Zhao, Muhammad Boota, Michel W. BarsoumAbstract:Herein we develop a chemical etching method to produce porous two-dimensional (2D) Ti3C2Tx MXenes at room temperature in aqueous solutions. The as-produced porous Ti3C2Tx (p-Ti3C2Tx) have larger specific surface areas and more open structures than their pristine counterparts, and can be fabricated into flexible films with, or without, the addition of carbon nanotubes (CNTs). The as-fabricated p-Ti3C2Tx/CNT films showed significantly improved lithium ion storage capabilities compared to pristine Ti3C2Tx based films, with a very high capacity of ≈1250 mAh g−1 at 0.1 C, excellent cycling stability, and good rate performance (330 mAh g−1 at 10 C). Using the same chemical etching method, we also made porous Nb2CTx and V2CTx MXenes. Therefore, this study provides a simple, yet effective, procedure to introduce pores into MXenes and possibly other 2D sheets that in turn, can enhance their electrochemical properties.
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kinetics of aluminum extraction from ti3alc2 in hydrofluoric acid
Materials Chemistry and Physics, 2013Co-Authors: Olha Mashtalir, Michael Naguib, Boris Dyatkin, Yury Gogotsi, Michel W. BarsoumAbstract:Abstract Herein we report on the influence of particle size, time and temperature on the kinetics – quantified by X-ray diffraction – of the selective extraction of Al from the ternary layered Transition Metal Carbide, Ti3AlC2, when powders of the latter are immersed in hydrofluoric acid. Transmission and scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermogravimetric analysis were also used to characterize the resulting powders. Increasing the temperature and immersion times, and decreasing the Ti3AlC2 particle size, led to faster conversion of Ti3AlC2 to its 2-D Ti3C2 counterpart. Arch-shaped edges at the ends of some Ti3C2 layers resembled graphene, corroborating the single-sheet structure of exfoliated Ti3C2. The removal of water and/or OH surface groups from Ti3C2 using drying in vacuum was also attempted.
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mxene a promising Transition Metal Carbide anode for lithium ion batteries
Electrochemistry Communications, 2012Co-Authors: Michael Naguib, Jeremy Come, Volker Presser, Boris Dyatkin, Michel W. Barsoum, Pierre-louis Taberna, Patrice Simon, Yury GogotsiAbstract:Herein we report on Li insertion into a new two-dimensional (2-D) layered Ti₂C-based material (MXene) with an oxidized surface, formed by etching Al from Ti₂AlC in HF at room temperature. Nitrogen sorption of treated powders showed desorption hysteresis consistent with the presence of slit-like pores. At 23 m² g-¹, the specific surface area was an order of magnitude higher than untreated Ti₂AlC. Cyclic voltammetry exhibited lithiation and delithiation peaks at 1.6 V and 2 V vs. Li+/Li, respectively. At C/25, the steady state capacity was 225 mAh g-¹; at 1C, it was 110 mAh g-¹ after 80 cycles; at 3C, it was 80 mAh g-¹ after 120 cycles; at 10C, it was 70 mAh g-¹ after 200 cycles. Since Ti₂C is a member of the MXene family - where M is an early Transition Metal and X is C and/or N - that to date includes Ti₃C₂, Ta₄C₃, TiNbC, and (V₀.₅,Cr₀.₅)₃C₂, our results suggest that MXenes are promising as anode materials for Li-ion batteries.
Dinesh D Kumar - One of the best experts on this subject based on the ideXlab platform.
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tribo mechanical properties of reactive magnetron sputtered Transition Metal Carbide coatings
Tribology International, 2017Co-Authors: Dinesh D Kumar, N Kumar, S Kalaiselvam, R Radhika, Arul Maximus Rabel, R JayavelAbstract:Abstract Hard and wear resistant coatings are useful to enhance the functional properties and improve the lifetime of mechanical components. This study proposes a relationship between microstructure and tribo-mechanical properties of TiC, CrC, ZrC and WC Transition Metal Carbide coatings. In these coatings, an amorphous carbon (a-C) matrix phase coexists with a crystalline TMC phase. Superior wear resistance of ZrC coatings followed by the TiC coating was observed and this was explained by improved crystallinity and a-C phase present in coatings. Wear mechanisms were proposed by chemical analysis of wear tracks using micro Raman spectroscopy and energy dispersive X-ray spectroscopy.
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reactive magnetron sputtered wear resistant multilayer Transition Metal Carbide coatings microstructure and tribo mechanical properties
RSC Advances, 2015Co-Authors: Dinesh D Kumar, N Kumar, S Kalaiselvam, R Radhika, S Dash, A K Tyagi, R JayavelAbstract:To enhance the performance and durability of mechanical components, surface properties need to be modified. In this work, a unique combination of Transition Metal Carbide (TMC) multilayer coatings (TiC/CrC, TiC/ZrC and TiC/WC) were deposited by reactive DC magnetron sputtering on 316LN steel substrates. GIXRD results showed the presence of an amorphous CrC phase in the TiC/CrC multilayer, whereas, crystalline TiC, ZrC and W2C phases were observed in their respective coatings. FESEM analysis indicated the non-columnar structures of TMC layers in all the samples, except the CrC layer in the TiC/CrC multilayer. Solid solutions of the TiC and WC layers at the interface were identified due to the migration of W atoms into the TiC crystal lattices. The poor crystalline nature of the TiC/CrC multilayer led to lower hardness and weak wear resistance. However, enhanced tribo-mechanical properties were observed in TiC/ZrC and TiC/WC multilayer coatings. This is explained by the improved crystallinity and enhanced resistance to plastic deformation. For the selected tribological parameters, abrasive, adhesive and combined abrasive/adhesive wear modes are the major governing factors in determining the wear behaviors of TiC/CrC, TiC/ZrC and TiC/WC coatings, respectively. The chemical stability of deformed wear tracks was observed by Raman spectroscopy.
R Jayavel - One of the best experts on this subject based on the ideXlab platform.
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tribo mechanical properties of reactive magnetron sputtered Transition Metal Carbide coatings
Tribology International, 2017Co-Authors: Dinesh D Kumar, N Kumar, S Kalaiselvam, R Radhika, Arul Maximus Rabel, R JayavelAbstract:Abstract Hard and wear resistant coatings are useful to enhance the functional properties and improve the lifetime of mechanical components. This study proposes a relationship between microstructure and tribo-mechanical properties of TiC, CrC, ZrC and WC Transition Metal Carbide coatings. In these coatings, an amorphous carbon (a-C) matrix phase coexists with a crystalline TMC phase. Superior wear resistance of ZrC coatings followed by the TiC coating was observed and this was explained by improved crystallinity and a-C phase present in coatings. Wear mechanisms were proposed by chemical analysis of wear tracks using micro Raman spectroscopy and energy dispersive X-ray spectroscopy.
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reactive magnetron sputtered wear resistant multilayer Transition Metal Carbide coatings microstructure and tribo mechanical properties
RSC Advances, 2015Co-Authors: Dinesh D Kumar, N Kumar, S Kalaiselvam, R Radhika, S Dash, A K Tyagi, R JayavelAbstract:To enhance the performance and durability of mechanical components, surface properties need to be modified. In this work, a unique combination of Transition Metal Carbide (TMC) multilayer coatings (TiC/CrC, TiC/ZrC and TiC/WC) were deposited by reactive DC magnetron sputtering on 316LN steel substrates. GIXRD results showed the presence of an amorphous CrC phase in the TiC/CrC multilayer, whereas, crystalline TiC, ZrC and W2C phases were observed in their respective coatings. FESEM analysis indicated the non-columnar structures of TMC layers in all the samples, except the CrC layer in the TiC/CrC multilayer. Solid solutions of the TiC and WC layers at the interface were identified due to the migration of W atoms into the TiC crystal lattices. The poor crystalline nature of the TiC/CrC multilayer led to lower hardness and weak wear resistance. However, enhanced tribo-mechanical properties were observed in TiC/ZrC and TiC/WC multilayer coatings. This is explained by the improved crystallinity and enhanced resistance to plastic deformation. For the selected tribological parameters, abrasive, adhesive and combined abrasive/adhesive wear modes are the major governing factors in determining the wear behaviors of TiC/CrC, TiC/ZrC and TiC/WC coatings, respectively. The chemical stability of deformed wear tracks was observed by Raman spectroscopy.
Yao Chu - One of the best experts on this subject based on the ideXlab platform.
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laser sculptured ultrathin Transition Metal Carbide layers for energy storage and energy harvesting applications
Nature Communications, 2019Co-Authors: Xining Zang, Cuiying Jian, Wanlin Wang, Mateo Follmar Diaz, Paul D Ashby, Taishan Zhu, Zheng Fan, Minsong Wei, Yao ChuAbstract:Ultrathin Transition Metal Carbides with high capacity, high surface area, and high conductivity are a promising family of materials for applications from energy storage to catalysis. However, large-scale, cost-effective, and precursor-free methods to prepare ultrathin Carbides are lacking. Here, we demonstrate a direct pattern method to manufacture ultrathin Carbides (MoCx, WCx, and CoCx) on versatile substrates using a CO2 laser. The laser-sculptured polycrystalline Carbides (macroporous, ~10-20 nm wall thickness, ~10 nm crystallinity) show high energy storage capability, hierarchical porous structure, and higher thermal resilience than MXenes and other laser-ablated carbon materials. A flexible supercapacitor made of MoCx demonstrates a wide temperature range (-50 to 300 °C). Furthermore, the sculptured microstructures endow the Carbide network with enhanced visible light absorption, providing high solar energy harvesting efficiency (~72 %) for steam generation. The laser-based, scalable, resilient, and low-cost manufacturing process presents an approach for construction of Carbides and their subsequent applications.