With concerns in energy crisis and global warming, researchers are actively investigating alternative energy renewable solutions. Among the various methods, piezoelectric transduction stands out due to its impressive ...With concerns in energy crisis and global warming, researchers are actively investigating alternative energy renewable solutions. Among the various methods, piezoelectric transduction stands out due to its impressive electromechanical coupling factor and coefficient. As a result, piezoelectric energy harvesting has garnered significant attention from the scientific community. In this study, we explored methods to enhance the piezoelectric properties of polyvinylidene fluoride (PVDF) through two distinct approaches. The first approach involved applying external high voltages at various stages during the mixture reaction. The goal was to determine whether this voltage application could alter or enhance PVDF’s piezoelectric conformation by improving the alignment of polarized dipoles. In the second part of our study, we investigated the effects of incorporating various nanostructures (including Iron Oxide, Magnesium Oxide, and Zinc Oxide) into PVDF. To analyze changes in PVDF’s crystalline structure, we utilized Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) techniques. Additionally, we measured the electric polarization of samples using a Precision LC Meter and examined the morphology of nanofibers through Scanning Electron Microscopy (SEM).展开更多
Li-S batteries have attracted considerable interest as nextgeneration energy storage devices owing to high energy density and the natural abundance of sulfur.However,the practical applications of Li-S batteries are ha...Li-S batteries have attracted considerable interest as nextgeneration energy storage devices owing to high energy density and the natural abundance of sulfur.However,the practical applications of Li-S batteries are hampered by the shuttle effect of soluble lithium polysulfides(LPS),which results in low cycle stability.Herein,a functional interlayer has been developed to efficiently regulate the LPS and enhance the sulfur utilization using hierarchical nanostructure of C3 N4(t-C3 N4)embedded with Fe304 nanospheres.t-C3 N4 exhibits high surface area and strong anchoring of LPS,and the Fe3 O4/t-C3 N4 accelerates the anchoring of LPS and improves the electronic pathways.The combination of these materials leads to remarkable battery performance with 400%improvement in a specific capacity and a low capacity decay per cycle of 0.02%at 2 C over 1000 cycles,and stable cycling at 6.4 mg cm-2 for high-sulfur-loading cathode.展开更多
Exfoliation of bulk graphitic carbon nitride(g‐C3N4)into two‐dimensional(2D)nanosheets is one of the effective strategies to improve its photocatalytic properties so that the 2D g‐C3N4 nanosheets(CN)have larger spe...Exfoliation of bulk graphitic carbon nitride(g‐C3N4)into two‐dimensional(2D)nanosheets is one of the effective strategies to improve its photocatalytic properties so that the 2D g‐C3N4 nanosheets(CN)have larger specific surface areas and more reaction sites.In addition,poly‐o‐phenylenediamine(PoPD)can improve the electrical conductivity and photocatalytic activity of semiconductor materials.Here,the novel efficient composite PoPD/AgCl/g‐C3N4 nanosheets was first synthesized by a precipitation reaction and the photoinitiated polymerization approach.The obtained photocatalysts have larger specific surface areas and could achieve better visible‐light response.However,silver chloride(AgCl)is susceptible to agglomeration and photocorrosion.The PoPD/AgCl/CN composite exhibits an extremely high photocurrent density,which is three times that of CN.Obviously enhanced photocatalytic activities of PoPD/AgCl/g‐C3N4 are revealed through the photodegradation of tetracycline.The stability of PoPD/AgCl/CN is demonstrated based on four cycles of experiments that reveal that the degradation rate only decreases slightly.Furthermore,.O2^-and h+are the main active species,which are confirmed through a trapping experiment and ESR spin‐trap technique.Therefore,the prepared PoPD/AgCl/CN can be considered as a stable photocatalyst,in which PoPD is added as a charge carrier and acts a photosensitive protective layer on the surface of the AgCl particles.This provides a new technology for preparing highly stable composite photocatalysts that can effectively deal with environmental issues.展开更多
In order to investigate the impedance matching properties of microwave absorbers,the ternary nanocomposites of GO/PANI/Fe3O4（GPF） are prepared via a two-step method,GO/PANI composites are synthesized by dilute polym...In order to investigate the impedance matching properties of microwave absorbers,the ternary nanocomposites of GO/PANI/Fe3O4（GPF） are prepared via a two-step method,GO/PANI composites are synthesized by dilute polymerization in the presence of aniline monomer and GO,and GO/PANI/Fe3O4 is prepared via a co-precipitation method.The obtained nanocomposites are characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD）,and Fourier transform infrared spectroscopy（FTIR）,respectively.The microwave absorbability reveals enhanced microwave absorption properties compared with GO,PANI,and GO/PANI.The maximum reflection loss of GO/PANI/Fe3O4 is up to-27 dB at 14 GHz with its thickness being 2 mm,and its absorption bandwidths exceeding-10 dB are more than 11.2 GHz with its thickness values being in the range from 1.5 mm-4 mm.It provides that GO/PANI/Fe3O4 can be used as an attractive candidate for microwave absorbers.展开更多
文摘With concerns in energy crisis and global warming, researchers are actively investigating alternative energy renewable solutions. Among the various methods, piezoelectric transduction stands out due to its impressive electromechanical coupling factor and coefficient. As a result, piezoelectric energy harvesting has garnered significant attention from the scientific community. In this study, we explored methods to enhance the piezoelectric properties of polyvinylidene fluoride (PVDF) through two distinct approaches. The first approach involved applying external high voltages at various stages during the mixture reaction. The goal was to determine whether this voltage application could alter or enhance PVDF’s piezoelectric conformation by improving the alignment of polarized dipoles. In the second part of our study, we investigated the effects of incorporating various nanostructures (including Iron Oxide, Magnesium Oxide, and Zinc Oxide) into PVDF. To analyze changes in PVDF’s crystalline structure, we utilized Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) techniques. Additionally, we measured the electric polarization of samples using a Precision LC Meter and examined the morphology of nanofibers through Scanning Electron Microscopy (SEM).
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(NRF-2019R1A2C1003594 and NRF-2019R1A2C1003551)。
文摘Li-S batteries have attracted considerable interest as nextgeneration energy storage devices owing to high energy density and the natural abundance of sulfur.However,the practical applications of Li-S batteries are hampered by the shuttle effect of soluble lithium polysulfides(LPS),which results in low cycle stability.Herein,a functional interlayer has been developed to efficiently regulate the LPS and enhance the sulfur utilization using hierarchical nanostructure of C3 N4(t-C3 N4)embedded with Fe304 nanospheres.t-C3 N4 exhibits high surface area and strong anchoring of LPS,and the Fe3 O4/t-C3 N4 accelerates the anchoring of LPS and improves the electronic pathways.The combination of these materials leads to remarkable battery performance with 400%improvement in a specific capacity and a low capacity decay per cycle of 0.02%at 2 C over 1000 cycles,and stable cycling at 6.4 mg cm-2 for high-sulfur-loading cathode.
基金supported by the National Natural Science Foundation of China(21576125,21776117)the China Postdoctoral Science Foundation(2017M611716,2017M611734)+1 种基金the Six talent peaks project of Jiangsu Province(XCL-014)the Zhenjiang Science&Technology Program(SH2016012)~~
文摘Exfoliation of bulk graphitic carbon nitride(g‐C3N4)into two‐dimensional(2D)nanosheets is one of the effective strategies to improve its photocatalytic properties so that the 2D g‐C3N4 nanosheets(CN)have larger specific surface areas and more reaction sites.In addition,poly‐o‐phenylenediamine(PoPD)can improve the electrical conductivity and photocatalytic activity of semiconductor materials.Here,the novel efficient composite PoPD/AgCl/g‐C3N4 nanosheets was first synthesized by a precipitation reaction and the photoinitiated polymerization approach.The obtained photocatalysts have larger specific surface areas and could achieve better visible‐light response.However,silver chloride(AgCl)is susceptible to agglomeration and photocorrosion.The PoPD/AgCl/CN composite exhibits an extremely high photocurrent density,which is three times that of CN.Obviously enhanced photocatalytic activities of PoPD/AgCl/g‐C3N4 are revealed through the photodegradation of tetracycline.The stability of PoPD/AgCl/CN is demonstrated based on four cycles of experiments that reveal that the degradation rate only decreases slightly.Furthermore,.O2^-and h+are the main active species,which are confirmed through a trapping experiment and ESR spin‐trap technique.Therefore,the prepared PoPD/AgCl/CN can be considered as a stable photocatalyst,in which PoPD is added as a charge carrier and acts a photosensitive protective layer on the surface of the AgCl particles.This provides a new technology for preparing highly stable composite photocatalysts that can effectively deal with environmental issues.
基金supported by the National Basic Research Program of China(Grant Nos.2011CB932700 and 2011CB932703)the National Natural Science Foundation of China(Grant Nos.61335006,61378073,and 61077044)+1 种基金the Beijing Natural Science Foundation,China(Grant No.4132031)the Fundamental Research Funds for the Central Universities of Beijing Jiaotong University,China(Grant No.2014YJS136)
文摘In order to investigate the impedance matching properties of microwave absorbers,the ternary nanocomposites of GO/PANI/Fe3O4（GPF） are prepared via a two-step method,GO/PANI composites are synthesized by dilute polymerization in the presence of aniline monomer and GO,and GO/PANI/Fe3O4 is prepared via a co-precipitation method.The obtained nanocomposites are characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD）,and Fourier transform infrared spectroscopy（FTIR）,respectively.The microwave absorbability reveals enhanced microwave absorption properties compared with GO,PANI,and GO/PANI.The maximum reflection loss of GO/PANI/Fe3O4 is up to-27 dB at 14 GHz with its thickness being 2 mm,and its absorption bandwidths exceeding-10 dB are more than 11.2 GHz with its thickness values being in the range from 1.5 mm-4 mm.It provides that GO/PANI/Fe3O4 can be used as an attractive candidate for microwave absorbers.
