Asian Journal of Organic Chemistry
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2017
·Vol. 7
·期 1
·240-247
·
IF 2.788
Rui Yan,Zhong-Xia Wang
Graphical Oxidative coupling of allylic alcohols : [Cp*RhCl 2 ] 2 was demonstrated to catalyze the oxidative coupling of alkenylpyridines with allylic alcohols through alkenyl C−H activation in the presence of AgOTf and AgOAc to afford β-alkenyl ketones and aldehydes in moderate to good yields. [Cp*RhCl 2 ] 2 was demonstrated to catalyze the oxidative coupling of alkenylpyridines with allylic alcohols through alkenyl C−H activation in the presence of AgOTf and AgOAc to afford β-alkenyl ketones and aldehydes in moderate to good yields. Allylic alcohol, 1-aryl and 1-alkyl allylic alcohols can be coupled with various alkenylpyridines. The reaction occurred at the γ-position of allylic alcohols and the cis -β-position of the alkenylpyridines.
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高影响因子
IONICS
·
2017
·Vol. 24
·期 9
·2555-2563
·
IF 2.062
Zhang Qingtang,Yan Chao,Guo Junhong,Wang Xiaomei
Mesoporous Li 2 FeSiO 4 /C nanocomposites (LFS-FNS and LFS-NS) were prepared from fumed nano silica (FNS) and nano silica (NS) through facile solid-state reactions, respectively. XRD analysis indicates that the crystalline structures of LFS-FNS and LFS-NS are indexed to monoclinic Li 2 FeSiO 4 of P2 1 . SEM results prove that the particle size of LFS-FNS and FNS (25~40 nm) is smaller than that of LFS-NS and NS, revealing the particle size of Li 2 FeSiO 4 /C nanocomposites can be tuned by choosing different silica. TEM further indicates Li 2 FeSiO 4 nanoparticles are uniformly dispersed in the amorphous carbon networking of LFS-FNS. Pore structure analysis indicates the external surface areas of LFS-FNS as well as LFS-NS are 51.4 and 36.1 m 2 g −1 , indicating the pore properties of mesoporous Li 2 FeSiO 4 /C nanocomposites can be controlled by using different silica as silicon resource. The reduced particle size and high external surface area shorten the lithium-ion diffusion path and make LFS-FNS possess better electrochemical performance over LFS-NS. The discharge capacity of LFS-FNS is as high as 172 mA h g −1 at 0.1 C.
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JOURNAL OF POWER SOURCES
·
2018
·
IF 6.945
Chao Wang,Youlong Xu,Xiaofei Sun,Baofeng Zhang,Yanjun Chen,Shengnan He
The Li 2 MnSiO 4 as a novel cathode material for lithium ion batteries, performs high specific capacity, high thermal stability, low cost and etc. However, it suffers from relatively low electronic conductivity and lithium ion diffusion rate. Herein, we successfully introduce fluorine to Li 2 MnSiO 4 (Li 2 MnSiO 4-x F x , x = 0.00, 0.01, 0.03 and 0.05) to overcome these obstacles. The results show that F doping not only enlarges the lattice parameters but also decreases the particle size, synergistically improving the lithium ion diffusion of Li 2 MnSiO 4 . Moreover, F doping increase electronic conductivity of Li 2 MnSiO 4 /C by inhibiting the formation of C-O bonds in the carbon layers . Meanwhile, F doping improves the crystallinity and stabilizes the crystal structure of Li 2 MnSiO 4 . Finally, the Li 2 MnSiO 3.97 F 0.03 /C with the best electrochemical performances delivers the initial specific discharge capacity of 279 mA h g −1 at 25mA g −1 current density from 1.5 V to 4.8 V. Also, it maintains a higher capacity (201 mA h g −1 ) than F-free Li 2 MnSiO 4 (145 mA h g −1 ) after 50 cycles.
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Journal of Energy Storage
·
2025
·
IF 9.8
Fuyu Chen,Zhongjie Wang,Xuhong Yin,Xiangdong Cheng,Qiang He,Hui Chen,Qinfang Zhang
The vanadium flow battery (VFB) has garnered significant attention for its potential to enable cost-effective utilization in large-scale energy storage. Nevertheless, the electrochemical activity of electrodes is limited during vanadium redox reactions, which poses a challenge to achieving high-performance VFBs. To address this, we synthesize a catalyst consisting of amorphous carbon, manganese oxide, and cobalt, to enhance VFB performance. Initially, bimetallic metal-organic frameworks with varying Mn Co ratios are synthesized using a hydrothermal method. Subsequently, the bimetallic metal-organic frameworks are carbonized to form the catalysts. The morphology, composition, electrocatalytic activity, and charging-discharging behavior of the prepared catalysts are then systematically investigated. This paper reveals that: i) the composite with a molar ratio of manganese to cobalt of 1:4, exhibits a uniform and fine particle distribution, an abundance of oxygen-containing functional groups, and exceptional electrochemical activities; ii) it enhances the energy efficiency of VFBs by 9 % compared to those utilizing raw carbon felts and by 5 % over those with mono-MnO@C or mono-Co@C electrodes at 100 mA cm −2 ; iii) it offers significant improvements in terms of operating voltages, cell capacities, high current density characteristics, and lifespan. Consequently, this work introduces a novel electrochemical catalyst for VFBs, enhancing their performance and broadening their potential applications.
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ACS Applied Polymer Materials
·
2024
·
IF 4.4
Hao-Jia Guo,Xiaodong Qiao,Ben-Xiang Hu,Shuangquan Liao,Ming-Chao Luo
The recycling of waste rubber (WR) is beneficial to the sustainable development of rubber industries. However, interactions among WR are weak, limiting the recycling of WR. In this work, our group designed bis-diazo compounds to promote interactions among WR for recycling through aliphatic C–H insertion strategies. Specifically, upon hot pressing, bis-diazo compounds produce bis-carbenes which react with C–H on the surface of WR by C–H insertions, and then we obtain recycled WR materials. As a result, stress–strain curves show that the strength of recycled WR increases steadily with the increase of bis-diazo compound loading, which has reached the level of butadiene styrene rubbers. Moreover, the introduced disulfide bonds endow recycled WR with reprocessability. Stress–relaxation experiments at different temperatures show that recycled WR with disulfide bonds have unique vitrimer viscoelastic properties. The feasibility of bis-diazo compounds to enhance interactions among WR through C–H insertions opens opportunities to recycle and reinvent industrial WR.
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ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Hong Li,Zhijian Peng,Jingwen Qian,Meng Wang,Chengbiao Wang,Xiuli Fu
Recently, WSe2 as a typical transition metal dichalcogenide compound has attracted extensive attention due to its potential applications in electronic and optoelectronic devices. However, WSe2 alone cannot be directly used as a photocatalyst due to its inferior performance possibly caused by the strong recombination of photogenerated electron–hole pairs. Here a novel C fibers@WSe2 nanoplates core–shell composite (NPCSC) was successfully synthesized via facile, one-step thermal evaporation, in which numerous WSe2 thin nanoplates were in situ, densely and even vertically grown on the surface of the C fibers. Such composite presents highly solar-driven photocatalytic activity and stability for the degradation of various organic aqueous dyes including methylene blue and rhodamine B, and highly harmful gases like toluene, showing the great potential for environmental remediation by degrading toxic industrial chemicals using sunlight. Under simulated sunlight irradiation, comparing with commercially available WSe2 powder, the as-synthesized C fibers@WSe2 NPCSC presents significantly enhanced reaction rate constants by a factor of approximately 15, 9, and 3 for the degradation of aqueous methylene blue, aqueous rhodamine B, and gaseous toluene, respectively, due to the effective separation of photogenerated electron–hole pairs promoted by the rapid transfer of photogenerated electrons through C fibers. Moreover, this one-step thermal evaporation is an easy-handling, environmentally friendly, and low-cost synthesis method, which is suitable for large-scale production.
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PubMed
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2024
·Vol. 31
·期 11
·2508-2517
·
IF 5.6
Zhang Yahong,Zhang Yi,Liu Huimin,Li Dan,Wang Yibo,Xu Chunchao,Tian Yuping,Meng Hongjie
Facing the complex variable high-temperature environment, electromagnetic wave (EMW) absorbing materials maintaining high stability and satisfying absorbing properties is essential. This study focused on the synthesis and EMW absorbing performance evaluation of TiN/Fe 2 N/C composite materials, which were prepared using electrostatic spinning followed by a high-temperature nitridation process. The TiN/Fe 2 N/C fibers constructed a well-developed conductive network that generates considerable conduction loss. The heterogeneous interfaces between different components generated a significant level of interfacial polarization. Thanks to the synergistic effect of stable dielectric loss and optimized impedance matching, the TiN/Fe 2 N/C composite materials demonstrated excellent and stable absorption performance across a wide temperature range (293–453 K). Moreover, TiN/Fe 2 N/C-15 achieved a minimum reflection loss (RL) of −48.01 dB and an effective absorption bandwidth (EAB) of 3.64 GHz at 2.1 mm and 373 K. This work provides new insights into the development of high-efficiency and stabile EMW absorbing materials under complex variable high-temperature conditions.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Lidan Tan,Sheng Zhou,Yi Jin,Hui Zhu,Qin Zhang,Jianguang Guo,Xuanke Li,Zhijun Dong,Nianjun Yang,Ye Cong
Niobium oxides are widely active in the arena of lithium-ion batteries due to their distinctive structure and rapid charging capability, nevertheless facing the serious challenge from their inherently low electrical conductivity. Herein, a molten salt method is proposed to prepare nickel niobate (NiNb 2 O 6 ) anode materials for lithium-ion batteries, and a carbon coating derived from mesophase pitch is fabricated to construct NiNb 2 O 6 @C composites. Importantly, NiNb 2 O 6 @C undergoes spontaneous electrochemical reconstruction to generate metallic Ni and amorphous Nb 2 O 5 during the initial charge/discharge cycle. The presence of the outer carbon layer not only serves as a uniform conductive coating to improve the conductivity and thereby deliver superior rate performance, but also effectively inhibits the stripping of Ni 0 to guarantee a great cycling stability. The synergistic effects of the dual conductive interfaces, consisting of the carbon layer and the Mott-Schottky heterojunction between amorphous Nb 2 O 5 and metallic Ni, culminate in exceptional electrochemical performance. Specifically, NiNb 2 O 6 @C-10% delivers impressive specific capacity of 436.3 mAh g −1 at 0.5C and conspicuous cycling stability, maintaining 86.3% capacity retention after 800 cycles at 10C. This work underscores the substantial potential of nickel niobate anode materials in advancing the development of next-generation lithium-ion batteries.
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Linyun Zhang,Shanxin Li,Xuzhou Jiang,Hongying Yu,Yijing Sun
Metal organic frameworks (MOFs) have been widely used as microwave absorption (MA) materials owing to their varied structures and large specific surface area. However, it is still challenging to endow MOF derivatives with a rational structure to achieve outstanding microwave absorption. In this work, the hollow Co@C nanorods (HCCN) with lots of winding carbon nanotubes on the surface are obtained based on a template-sacrificing method which employs ZnO nanorods as templates and ZIF67 nanoparticles as ornaments. The HCCNs possess large pore size and specific surface area, efficiently improving the impedance matching . The 1D structure, abundant heterointerfaces and defects trigger strong conduction loss, interfacial and dipole polarization, respectively. Therefore, HCCNs exhibits excellent MA properties: the strong reflection loss of −66.8 dB at the thickness of 2.1 mm and the effective absorption bandwidth of 5.68 GHz at 2.5 mm. Radar cross section (RCS) simulation results have confirmed the practicality of HCCNs. This study proposes an inspiration for the structural designing of MOF materials and derivatives to realize amazing MA performance.
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高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Zhijiao Huang,Yong Liu,Lungang Chen,Xinghua Zhang,Jianguo Liu,Chenguang Wang,Qi Zhang,Longlong Ma
2,5-dimethylfuran (DMF), a promising biomass-derived fuel, is synthesized via the hydrodeoxygenation of 5-hydroxymethylfurfural (HMF). This study focuses on the inherent activity of a 5Pt5Fe/C catalyst for HMF hydrodeoxygenation to DMF. The catalyst exhibited exceptional performance, achieving a remarkable DMF yield of 99.6 %. It displayed specific selectivity for C = O bond hydrogenation and C O bond cleavage in diverse substrates, producing high yield of 2-methylfuran from furfural and furfury alcohol, and high yield of toluene from benzaldehyde, benzyl alcohol. In-depth characterizations unveiled valuable insights into the 5Pt5Fe/C catalyst's properties, emphasizing a harmonious balance between metal and acid sites due to the interactive synergy between Pt and Fe species, enhancing hydrodeoxygenation activity. Additionally, the catalyst demonstrated satisfactory stability, maintaining a commendable DMF yield over five reaction cycles despite observed changes.
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DIAMOND AND RELATED MATERIALS
·
2025
·
IF 5.1
Yingying Zhou,Chenyu Zhu,Haonan Du,Jinlei Wu,Chaoqun Yang,Shanshan Xiao,Wen Zheng,Rui Xin,Yikun Yang,Enyuan Zhen,Zhaowen Ren,Hui Xie
Magneto-carbon composites are promising materials for mitigating electromagnetic pollution due to combined dielectric and magnetic loss mechanisms. However, such absorbers often have unsatisfactory wave-absorbing properties due to the difficulty in matching the magnetic permeability with the dielectric properties. The multilayered hollow carbon cubes anchored to a ternary FeCoNi alloy were fabricated using a self-tempered engineering strategy. The multilayer structures are formed in two steps and have an iron cobalt-nickel alloy core encapsulated in a hollow cubic carbon shell. Initially, a phenolic resin (PR)-coated FeCoNi-Prussian blue analogue (PBA) was prepared, followed by high-temperature vacuum pyrolysis. The inner carbon layer, derived from PBA, exhibits high crystallinity, while the outer PR-derived carbon layer is amorphous, preventing agglomeration of the carbonized FeCoNi alloy particles. The amorphous outer layer enables electromagnetic waves to be better absorbed and consumed within the absorber due to its ability to effectively modulate conductivity and impedance matching. By leveraging heterogeneous interface polarization and modulating electrical conductivity through control of graphite crystallinity, a minimum reflection loss (RL min ) of −74.2 dB and an effective absorption bandwidth (EAB) of 5.8 GHz across the 2–18 GHz range were achieved. The study provides an effective approach to broaden the application prospects of advanced magneto-carbon composite absorbers by using a multilayer structure to achieve a balance between magnetic loss and dielectric properties.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Wei Ling,Peng Liao,Jiawei Zhu,Jianxin Wu,Caiwei Hu,Xianke Zhang,Jujun Yuan,Zuzhou Xiong,Xiurong Zhu,Chuicai Rong
Metal–organic framework (MOF) derivatives have emerged as promising candidates for designing lightweight, high-performance electromagnetic wave absorption (EMWA) materials owing to their tunable porosity, compositional diversity, and structural flexibility. In this study, a hybrid material (Nd/Fe-MOF) comprising Nd- and Fe-based MOFs was constructed via ion-exchange engineering based on an MOF-plus-MOF strategy, involving partial exchange between Nd³⁺ and Fe³⁺ ions. The subsequent pyrolysis of Nd/Fe-MOF yielded a particle-decorated bundle-like Nd 2 O 3 /Fe@C nanocomposite, which exhibited an exceptional EMWA performance with a minimum reflection loss (RL min )of −60.13 dB and an effective absorption bandwidth (EAB) of 5.0 GHz at a thin thickness of 1.8 mm. Moreover, Nd 2 O 3 /Fe@C also displayed an enhanced absorption with an EAB of 2.1 GHz (5.2–7.3 GHz) at low-frequency C band. This outstanding EMWA behavior can be attributed to the optimized impedance matching induced by the introduction of Nd 2 O 3 , and the prolonged propagation paths of EMW caused by the bundle-like structure. In order to present the practical application, CST simulation showed that the reduction value of radar cross section (RCS) of Nd 2 O 3 /Fe@C could reach up to 32.6 dB m² compared to the pure perfect electric conductor (PEC) substrate. Therefore, this study demonstrates the feasibility of employing ion-exchange engineering for the optimization of electromagnetic parameters and the subsequent development of high-efficiency rare earth–based absorbers.
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