COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
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2020
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IF 6.444
Hongsheng Liang,Hui Xing,Ming Qin,Hongjing Wu
In recent years, the development of an electromagnetic wave (EMW) absorbing material with low cost, wide bandwidth and strong absorption strength has been widely explored. In this study, SCFs@Fe 3 O 4 was used as the precursor (S1), and two methods are explored to ameliorate the ultra-high complex permittivity. The method of adding phenolic resin has achieved ideal results, and its bamboo-like SCFs@Fe 3 O 4 @phenolic resin (PR) (S5) has excellent property. In addition, the electromagnetic properties can be improved by calcining the precursor at 700 °C in a tubular furnace protected by Ar gas, and the obtained honeycomb-like porous SCFs@Fe 3 O 4 @FeO (S4) composite has superior EMW absorption performance. The excellent EMW absorption performance comes from its unique porous structure. The sample also has a dual loss mechanism of dielectric and magnetic loss. Among them, conduction loss, interfacial polarization, Debye relaxation, hysteresis loss, natural ferromagnetic resonance and exchange resonance play an important role in the process of EMW absorption. It exhibits an effective absorption bandwidth (EAB) of 6.1 GHz with a thin thickness of 1.9 mm. Noting that, by adjusting the thickness (1–5 mm), reflection loss ( RL ) lower than −10 dB can be achieved in the range of 4–18 GHz, which covers the entire C, X and Ku bands. In this study, we not only successfully prepared honeycomb-like porous SCFs@Fe 3 O 4 @FeO and bamboo-like SCFs@Fe 3 O 4 @PR, but also proposed two simple methods to solve the excessively high complex permittivity of carbon materials. This has important reference value for the subsequent research of EMW absorbing materials.
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Nanomaterials
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2020
·Vol. 10
·期 5
·828
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IF 4.324
Yun Zhou,Qiujie Ding,Yuan Wang,Xiaoping OuYang,Lixin Liu,Junyu Li,Bing Wang
In this paper, TiO2/Ag2V4O11nanoheterojunctions have been synthesized by hydrothermal methods, which show enhanced photocatalytic activity compared to TiO2under visible light. Moreover, the TiO2/Ag2V4O11nanoheterojunction with set molar ratio of 2:1, referred to as TA2, show the highest visible light photocatalytic activity, which could decompose about 100% RhB molecules within 80 min of irradiation with visible light. Specially, the time-resolved photoluminescence spectrum of TA2 demonstrates that the free exciton recombination occurs in approximately 1.7 ns, and the time scale for Shockley–Read–Hall recombination of photogenerated electrons and holes is prolonged to 6.84 ns. The prolonged timescale of TA2 compared to TiO2and Ag2V4O11can be attributed to the carrier separation between nanojunctions and the carrier capture by interfacial defects. Furthermore, the enhanced photocatalytic activity of TiO2/Ag2V4O11nanoheterojunctions also benefits from the synergistic effect of the broadened absorption region, higher photocarrier generation, longer carrier lifetime, and quicker collection dynamics.Keywords:TiO2/Ag2V4O11;nanoheterojunctions;photocatalyst;interface effect;carrier capture;recombination kinetics
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高影响因子
APPLIED SURFACE SCIENCE
·
2020
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IF 6.182
Siyuan Li,Yi Jiang,Wenchao Jiang,Yu Zhang,Kai Pan,Song Wang,Chongyang Hu,Lu-Hua Zhang,Lixin Xia
Constructing a heterojunction photoelectrode is an effective way to promote the photogenerated charge separation in photoelectrochemical (PEC) water oxidation. In this work, we successfully fabricated C 3 N 4 /BiVO 4 hybrid electrodes by integrating g-C 3 N 4 onto the nanoporous BiVO 4 via a simple in-situ synthesis method. The as-prepared C 3 N 4 /BiVO 4 photoanodes were systematically studied by Electrochemical Impedance Spectroscopy, steady-state surface photovoltage (SPV), transient SPV, Open circuit potential and Photoluminescence measurements. With an optimal loading of g-C 3 N 4 , the 2-C 3 N 4 /BiVO 4 electrode showed a high photocurrent density of 4.06 mA/cm 2 at 1.23 V (vs. RHE) for water oxidation, a 2.8 times enhancement over that of the BiVO 4 . It is found that g-C 3 N 4 improved the PEC performance of the photoanodes by simultaneously promoting the charge separation and surface reaction kinetics. When a NiOOH co-catalyst was immobilized onto the 2-C 3 N 4 /BiVO 4 electrode, both the PEC property and stability of the photoanode were enhanced. An extremely high photocurrent density of 5.44 mA/cm 2 at 1.23 V was achieved. The largest half-cell solar energy conversion efficiency for NiOOH/2-C 3 N 4 /BiVO 4 was 1.43% at 0.78 V, corresponding to 8.4 times that of unmodified BiVO 4 (0.17% at 0.97 V). This work brings new insight into the development of C 3 N 4 -based devices for application in solar to fuel conversion.
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Journal of Nanomaterials
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2020
·
IF 1.98
Yuan Xu,Jian-Wei Zhu,Jun-Bo Fang,Xiao Li,Miao Yu,Yun-Ze Long
Separators are key materials to ensure the safety of lithium-ion batteries and improve their performance. Currently, commercial lithium-ion battery separators are mainly polyolefin organic diaphragms, but their temperature instability leads to battery short circuit and fire risk. A flexible SiO2 nanofiber membrane combined with a poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) nanofiber membrane is prepared by an electrospinning method. The mechanical strength of the SiO2/PVDF-HFP composite nanofiber membrane (SPF) is twice as high as the pure SiO2 nanofiber membrane and at 200°C, there are almost no dimensional changes of the SPF separators. Compared to commercial polyethylene (PE) separators, SPF shows excellent thermal stability and large-area closed cells at 180°C when used in lithium-ion battery separators. The porosity of SPF is 89.7%, which is more than twice than that of an ordinary PE separator. The liquid absorption rate of SPF is much higher than an ordinary PE separator and has reached 483%. Furthermore, the cycle and rate performance of lithium-ion batteries prepared by SPF has been improved significantly. These excellent properties, as well as the potential for large-scale production of electrospinning technology, make SPF an ideal choice for high-power battery separators.
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CHINESE CHEMICAL LETTERS
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2021
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IF 6.779
Decai Yang,Yachao Xu,Kai Pan,Chuanxin Yu,Jiaxing Wu,Mingxia Li,Fan Yang,Yang Qu,Wei Zhou
Surface oxygen vacancy defects of mesoporous CeO 2 nanosheets assembled microspheres (D-CeO 2 ) are engineered by polymer precipitation, hydrothermal and surface hydrogenation strategies. The resultant D-CeO 2 with a main pore diameter of 9.3 nm has a large specific surface area (~102.3 m 2 /g) and high thermal stability. The mesoporous nanosheets assembled microsphere structure prevents the nanosheets from aggregation, which is beneficial to effective mass transfer and shortens the migration distance of charge carriers. After surface hydrogenation, the photoresponse extends to long wavelength region, combing with the band gap from 2.63 eV reduced to 2.39 eV. Under AM 1.5 G radiation, the photocatalytic degradation rate of tetracycline (TC) can be up to 99.99%, which is three times as high as that of pristine CeO 2 microspheres . The excellent solar-driven photocatalytic performance can be attributed to the efficient surface oxygen vacancy engineering and the mesoporous nanosheets assembled microsphere structure, which narrows the band gap, shortens the migration distance of carriers, promotes the spatial separation of photogenerated electron-hole pairs and favors mass transfer. The strategy provides new insights for fabricating other high-efficient oxide photocatalysts .
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SEPARATION AND PURIFICATION TECHNOLOGY
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2021
·
IF 7.312
Chun Pei,Pi-yu Chen,Si-Cheng Kong,Junlin Wu,Ji-Hua Zhu,Feng Xing
Chemical swelling and electrochemical oxidation are combined to realize the separation and recovery of carbon fibers from carbon fiber-reinforced plastic (CFRP) in dimethyl sulfoxide (DMSO) at normal temperature and pressure. The results showed that the depolymerization rate of epoxy resin in CFRP increased with increasing ammonium acetate concentration and current density, and the influence of the current density was more significant than that of the concentration. Microscopic analysis showed that the recycled carbon fibers had few residual resin on their surfaces and mild electrochemical oxidation etching, and recycled carbon fiber monofilament achieved a tensile strength and an interfacial shear strength that were 93.55% and 118.76% those of the original fibers.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Yuxuan Zhao,Lingzhi Nie,Hongli Yang,Kai Song,Huilin Hou
In present work, we report the fabrication of mesoporous TiO 2 /In 2 O 3 nanofibers photocatalyst via the combination of electrospinning and hydrothermal method , in which In 2 O 3 were uniformly grown on electrospun TiO2 nanofibers. The mass loading of In 2 O 3 nanostructures and mesoporous nanostructure could be easily controlled by adjusting raw materials weight of In 2 O 3 within the hydrothermal solutions. The as-prepared photocatalyst were also employed to study their photocatalytic performance for organic decomposition. It is found that TiO 2 /In 2 O 3 composites showed significantly enhanced photocatalytic efficiency as compared to that of pristine TiO 2 and In 2 O 3 photocatalysts for RhB degradation. The enhanced performance could be attributed to the combined effects of the extended visible-light response range, efficient separation of photo-excited charge carriers and increased reaction active sites.
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CARBON
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2021
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IF 9.594
Chao Zhang,Huifeng Dong,Binling Chen,Tianxu Jin,Jun Nie,Guiping Ma
The development of bifunctional activity and long durability of ORR/OER catalyst is vital for realizing the practical application of Zn–air batteries (ZAB). Herein, 3D-structured bifunctional catalysts , CoFe nanoalloy decorated carbon nanotubes (CNT) anchoring with 2D MXene (Fe/Co-CNT@MXene-T), were prepared and fabricated as the cathode for both aqueous and flexible ZAB. Taking advantages of active sites of CoFe nanoparticles , robust sheath and fast charge transfer provided by CNT and MXene, our optimal catalyst Fe/Co-CNT@MXene-8 exhibited remarkable electroactivities of ORR and OER comparable with the benchmark Platinum carbon (Pt/C) and Ruthenium dioxide (RuO 2 ), respectively. The as-assembled aqueous ZAB with Fe/Co-CNT@MXene-8 as cathode exhibited a high specific capacity of 759 mA h g −1 at a current density of 10 mA cm −2 , and a stable voltage platform in the quick discharge–charge test under a 375h long-lasting operation, superior to those assembled with benchmark commercial catalyst and other reported catalysts. Furthermore, the as-assembled flexible ZAB with Fe/Co-CNT@MXene-8 as cathode also presented excellent durability cycling and showed promising perspectives as future power sources for wearable application. Such high performance was also verified by X-ray absorption near-edge structure (XANES) and supported by density functional theory (DFT) calculation. This work provides a novel view to design highly effective and long-lasting rechargeable ZABs.
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Insect Science
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2021
·Vol. 29
·期 2
·363-378
·
IF 3.262
Jia-Bao Lu,Jian-Sheng Guo,Xuan Chen,Chen Cheng,Xu-Mei Luo,Xiao-Ya Zhang,Bernard Moussian,Jian-Ping Chen,Jun-Min Li,Chuan-Xi Zhang
Many holo- and hemimetabolous insects enhance their eggshells during embryogenesis by forming a serosal cuticle (SC). To date, scholarly understanding of the SC composition and SC-related gene functions has been limited, especially for hemimetabolous insects. In this study, we initially performed transmission electron microscopic (TEM) observation and chitin staining of the SC in Nilaparvata lugens , a hemimetabolous rice pest known as the brown planthopper (BPH). We confirmed that the SC was a chitin-rich lamellar structure deposited gradually during the early embryogenesis. Parental RNA interference (RNAi) against Nilaparvata lugens chitin synthase 1 ( NlCHS1 ) in newly emerged and matured females resulted in decreases of egg hatchability by 100% and 76%, respectively. Ultrastructural analyses revealed loss of the lamellar structure of the SC in ds NlCHS1- treated eggs. According to temporal expression profiles, five cuticle protein coding genes, NlugCpr1/2/3/8/90 , were specifically or highly expressed during the SC formation period, and NlugCpr1/2/3/90 were further detected in 72 h eggshells extract by ultra-performance liquid chromatography-tandem mass spectrometry/mass spectrometry. NlugCpr2/3/90 were likely three SC-specific cuticle proteins. TEM observations of the SC following parental RNAi against NlugCpr1 / 2 / 3 / 8 / 90 demonstrated that NlugCpr3 / 8 / 90 were essential for SC formation. The study provided an understanding of the SC formation process and SC-related cuticle proteins in BPHs, which offer potential targets for pest control in the egg stage as well.
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高影响因子
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 38
·21695-21702
·
IF 12.732
Xiaojie Shen,Guangyu Zhao,Xianbo Yu,Huihuang Huang,Ming Wang,Naiqing Zhang
Undesirable lithium dendrite growth limits the application of lithium metal anodes in high-energy storage batteries. Here, multifunctional SnSe–C composite modified 3D scaffolds are constructed to achieve dendrite-free lithium deposition. During the initial lithiation stage, the porous SnSe–C composite converts into a Li–Sn alloy and Li2Se by lithium reduction. The lithiophilic Li–Sn alloy exhibits a low nucleation barrier and realizes homogeneous lithium nucleation. The reductive product Li2Se with a high ionic conductivity facilitates lithium ion transport, which helps realizing the homogeneous lithium ion flux and reducing concentration polarization. Benefitting from the synergistic effect of the Li–Sn alloy and Li2Se, the Li/SnSe–C anode exhibits an ultralong lifespan over 1100 h with a low overpotential of 18 mV. In full-cell configurations with LiFePO4 cathodes, the Li/SnSe–C anode demonstrates enhanced rate capability and cycle stability with a high-capacity retention of 85% over 750 cycles. This work prepares multifunctional SnSe–C composite modified 3D scaffolds to regulate lithium nucleation and transport, which offers new insights and opportunities for developing dendrite-free lithium metal battery technology.
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CARBON
·
2021
·
IF 9.594
Hongsheng Liang,Hui Xing,Zhenhui Ma,Hongjing Wu
The development of electromagnetic wave (EMW) shielding and absorbing materials for flexible devices with carbon cloth and cotton cloth as the substrate has been widely reported. However, the utilization of incorrect test methods in recent reports led to the test data erroneously exhibits the actual absorption performance of the flexible absorber, which confuses the cognition of shielding and the absorbent. Moreover, previous studies are mostly based on semi-empirical rules and lack data relationships between absorption and characterization. The dominant dissipation mechanism in EMW absorbent materials demands to be resolved. Hence, we compared the EMW absorption capacity of the hierarchical carbon cloth@NiCo 2 O 4 /NiO hybrid via the waveguide method and the coaxial method. Specifically, the flexible absorber with integrated structure is unfavorable for incident waves to enter its interior due to its skin depth and extremely high conductivity. However, the absorbers made into a paraffin ring showed obvious optimization. Enhanced interfacial polarization is confirmed as the dominant mechanism of EMW dissipation via various characterization and analysis of electromagnetic (EM) parameters. This work provides an insight into the misunderstanding of the rational design of flexible absorbent materials for the first time, which is of great significance to the research of flexible electronic countermeasure materials.
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WEAR
·
2021
·
IF 3.892
Tiancheng Ouyang,Wenwu Lei,Wentao Tang,Yudong Shen,Chunlan Mo
The development of eco-friendly lubricant is the requirement of the times. In this paper, the modified IF-WS 2 nanoparticles are added to castor oil as additives to prepare mixed lubricant. The lubrication performances of the mixed oil are investigated by ball-on-disc rotary friction tester, and then the surface scratches are characterized by depth of field digital microscope, scanning electron microscope and Raman spectrometer. Experiments reveal that compared with the base oil, the friction coefficient and worn volume decrease by 27.4% and 47.2% after adding modified IF-WS 2 as additives under 300 rpm and 5 N conditions, respectively. From mechanism analysis, this improvement in lubrication performance is attributed to the polarity of castor oil and the unique pressure bearing structure and dispersion stability of modified IF-WS 2 , which makes that the castor oil molecules can better adsorb around the modified IF-WS 2 to form heavy loading bearing friction oil film so as to reduce friction and wear. In summary, results indicate the mixture of modified IF-WS 2 nanoparticles and vegetable lubricating oil has an attractive prospect in the field of environmentally-friendly products.
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