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434 results on '"Xi, Jingyu"'

113. Carbon Microtube Textile with MoS2 Nanosheets Grown on Both Outer and Inner Walls as Multifunctional Interlayer for Lithium–Sulfur Batteries.

Author

Yang, Jiaye, Yu, Lihong, Zheng, Bangbei, Li, Narui, Xi, Jingyu, and Qiu, Xinping

Subjects
LITHIUM sulfur batteries, COTTON textiles, MOLYBDENUM disulfide, POLYSULFIDES, TEXTILES, HYDROGEN evolution reactions, LITHIUM cells
Abstract

The shuttle effect of soluble lithium polysulfides during the charge/discharge process is the key bottleneck hindering the practical application of lithium–sulfur batteries. Herein, a multifunctional interlayer is developed by growing metallic molybdenum disulfide nanosheets on both outer and inner walls of cotton cloth derived carbon microtube textile (MoS2@CMT). The hollow structure of CMT provides channels to favor electrolyte penetration, Li+ diffusion and restrains polysulfides via physical confinement. The hydrophilic and conductive 1T‐MoS2 nanosheets facilitate chemisorption and kinetic behavior of polysulfides. The synergic effect of 1T‐MoS2 nanosheets and CMT affords the MoS2@CMT interlayer with an efficient trapping‐diffusion‐conversion ability toward polysulfides. Therefore, the cell with the MoS2@CMT interlayer exhibits enhanced cycling life (765 mAh g−1 after 500 cycles at 0.5 C) and rate performance (974 mAh g−1 at 2 C and 740 mAh g−1 at 5 C). This study presents a pathway to develop low‐cost multifunctional interlayers for advanced lithium–sulfur batteries. [ABSTRACT FROM AUTHOR]

Published
2020
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126. Simultaneously Providing Iron Source toward Electro-Fenton Process and Enhancing Hydrogen Peroxide Production via a Fe3O4Nanoparticles Embedded Graphite Felt Electrode

Author

Lian, Tingting, Huang, Chao, Liang, Feng, Li, Xinyong, and Xi, Jingyu

Abstract

Electro-reduction of O2to generate H2O2is an attractive alternative to the current anthraquinone process and quite necessary for chemical industries and environmental remediation. In general, sufficient porous structure contributes to expose more catalytic active sites and shorten diffusion paths for the heterogeneous catalysis of O2. In this work, initially the Fe3O4nanoparticles embedded graphite felt (Fe3O4@GF) is prepared through a mild hydrothermal following with thermal reduction method. This special combination not only provides iron source for the electro-Fenton reaction but also supplies rich active sites from the Fe3O4embedded structure with abundant cracks, which are beneficial to increase the reaction rate. Compared with raw graphite felt (RGF), fresh Fe3O4@GF exhibits superior pollutant degradation kinetics with more than 400% increase and approximately 37.8% improvement to the removal of total organic carbon. A 98% decolorization of rhodamine B (RhB) can be achieved in just 5 min and quickly completes 100% removal of RhB in the next few seconds. As the electro-Fenton reaction progresses, Fe3O4dissolves in the electrolyte, leaving a porous structure on the surface of the GF to form a porous GF (PGF), and the rapid radical reaction activates the GF surface. Both the chemical etching of Fe3O4and the electro-Fenton process can further increase the specific surface area, defects, and actives sites of the electrode. As expected, the active PGF exhibits favorable performance of H2O2production in electrolytes of different pHs: 1 (320.0 ± 36.5 mg L–1), 3 (301.9 ± 13.2 mg L–1), and 7 (320.4 ± 21.2 mg L–1). The degradation performance of PGF does not significantly decay even after 20 cycles of repeated use, indicating the good structural stability and long-term durability. The superiority of the in situ Fe source and fast reaction kinetics for electro-Fenton of Fe3O4@GF is confirmed, and this holey engineered strategy also provides the possibility to achieve swift water purification and open up a new way for developing efficient carbon-based electrodes.

Published
2019
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135. Synthesis of highly active SnO2-CNTs supported Pt-on-Au composite catalysts through site-selective electrodeposition for HCOOH electrooxidation

Author

Zhang Lei, Wang Liu-cheng, Song Cheng-ying, Guo Xun, Zhao Jian-hong, Wang Jianshe, Xi Jingyu, and Zhang Jiujun

Subjects
Materials science, X ray diffraction, General Chemical Engineering, Composite number, Inorganic chemistry, Nanoparticle, Morphology and composition, Formic acid, High resolution transmission electron microscopy, Carbon nanotube, Electrochemistry, Redox, Catalysis, law.invention, law, Site selective, Electrochemical measurements, High-resolution transmission electron microscopy, Gold deposits, Platinum, Thermal transformations, Glassy carbon electrodes, Tin, Synthesis (chemical), High performance composites, Excitons, Glass membrane electrodes
Abstract

In this paper, site-selective electrodeposition method is developed to prepare Pt-on-Au composite catalysts for HCOOH electrooxidation. In the synthesis, Au nanoparticles are prepared through reduction of NaAuCl 4 by Sn(OH) 2 supported on carbon nanotubes and after thermal transformation of Sn(OH) 2 to SnO 2 , composite supports (Au/SnO 2 -CNTs) were obtained. By adjusting the potential of Au/SnO 2 -CNTs coated glassy carbon electrode, Pt entities are selectively deposited on Au particles to form SnO 2 -CNTs supported Pt-on-Au composite catalysts. The morphology and composition of the formed composite catalysts are characterized by instrument techniques such as X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The site-selectivity of Pt electrodeposition on Au is confirmed by electrochemical measurements. The composite catalysts are tested to have high Pt mass activity toward HCOOH oxidation reaction, demonstrating that the synthesis method developed in this paper has promising potential for developing high performance composite catalysts. The Pt content effect on the catalytic activity is also tested for catalyst performance optimization.

Published
2013

136. Nickel–Copper Alloy Encapsulated in Graphitic Carbon Shells as Electrocatalysts for Hydrogen Evolution Reaction.

Author

Shen, Yi, Zhou, Yongfang, Wang, Duo, Wu, Xi, Li, Jia, and Xi, Jingyu

Subjects
COPPER-nickel alloys, MICROENCAPSULATION, GRAPHITE, CARBON, ELECTROCATALYSTS, HYDROGEN evolution reactions
Abstract

Abstract: Searching for cost‐effective and high‐performance electrocatalysts for hydrogen production is of paramount importance. Herein, nickel‐copper (NiCu) alloy nanoparticles are encapsulated into graphitic shells via an ambient‐pressure chemical vapor deposition process. The resulting carbon‐encapsulated NiCu (denoted as NiCu@C) composite possesses a well‐defined core–shell structure with tunable thicknesses of the shells and is examined as electrocatalysts for the hydrogen evolution reaction (HER) in acidic, neutral, and alkaline solutions. Electrochemical measurements indicate that the activity of the NiCu@C highly depends on the thickness of the shell. Single‐layered graphene encapsulated NiCu nanoparticles show remarkable HER activity and durability. To obtain a current density of 10 mA cm−2, overpotentials of 48, 164, and 74 mV are needed in electrolyte solutions with pH = 0, 7, and 14, respectively. Such low overpotentials render the composite as one of the most active nonprecious electrocatalysts. Accelerated durability tests demonstrate that the NiCu@C catalysts exhibit excellent stability. Density function theory calculations are conducted to investigate the electronic structures of the NiCu@C. It is found that the representative Ni43Cu12@C240 model shows an ideal adsorption energy of hydrogen (−0.03 eV), manifesting its high HER activity. [ABSTRACT FROM AUTHOR]

Published
2018
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144. Broad temperature adaptability of vanadium redox flow battery–part 4: Unraveling wide temperature promotion mechanism of bismuth for V2+/V3+couple

Author

Liu, Yuchen, Liang, Feng, Zhao, Yang, Yu, Lihong, Liu, Le, and Xi, Jingyu

Abstract

Image, graphical abstractBismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range, while promote the V2+/V3+redox reaction, resulting in outstanding rate performance, excellent durability and broad temperature adaptability of vanadium flow batteries.

Published
2018
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145. Holey-engineered electrodes for advanced vanadium flow batteries

Author

Liu, Yuchen, Shen, Yi, Yu, Lihong, Liu, Le, Liang, Feng, Qiu, Xinping, and Xi, Jingyu

Abstract

Vanadium flow battery (VFB) has received tremendous attention because of its advantages such as long lifespan, easy to scale and flexible operation. Fabricating novel electrodes with high power density and wide operating temperature is critical to promote the practical application of VFB for all-climate energy storage. In this work, we describe a well-controlled method to prepare holey-engineered porous graphite felt (PGF) electrodes, in which nanosized pores are evenly distributed on the microscale graphite fibers of the graphite felt. Owing to its excellent electrolyte wettability and greatly enhanced surface area, the as-prepared PGF electrode exhibits high electrochemical activity towards VO2+/VO2+and V2+/V3+redox couples. As a result, the VFB single cell assembled with PGF electrodes demonstrates outstanding rate performance under current density up to 300mAcm−2. The resulting PGF electrode also exhibits superior long-term stability over 3000 charging-discharging cycles at a high current density of 150mAcm−2, and wide temperature adaptability from − 20°C to 60°C.

Published
2018
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