A strong interface coupling is of vital importance to develop metal oxide/carbon nanocomposite anodes for next-generation lithium ion batteries.Herein,a rational N-doped carb on riveting strategy is designed to boost ...A strong interface coupling is of vital importance to develop metal oxide/carbon nanocomposite anodes for next-generation lithium ion batteries.Herein,a rational N-doped carb on riveting strategy is designed to boost the lithium storage performance of Fe3O4/N-doped carbon tubular structures.Poly pyrrole(PPy)has been used as the precursor for N-doped carbon.N-doped carbon-riveted Fe3O4/N-doped carbon(N-C@Fe3O4@N-C)nanocomposites were obtained by pyrolysis of PPy-coated FeOOH@PPy nanotubes in Ar atmosphere.When tested as an anode for LIBs,the N-C@Fe3O4@N-C displays a high reversible discharge capacity of 675.8 mA h g-1 after 100 cycles at a current density of 100 mA g-1 and very good rate capability(470 mA h g_1 at 2 A g-1),which significantly surpasses the performance of Fe3O4@N-C.TEM analysis reveals that after battery cycling the FeOx particles detached from the carbon fibers for Fe3O4@N-C,while for N-C@Fe3O4@N-C the FeOx particles were still trapped in the carbon matrix,thus preserving good electrical contact.Consequently,the superior performance of N-C@Fe3C)4@N-C is attributed to the synergistic effect between Fe3O4 and N-doped carbon combined with the unique structure properties of the nanocomposites.The strategy reported in this work is expected to be applicable for designing other electrode materials for LIBs.展开更多
In this study, a simple, reliable and accurate method for the simultaneous separation and determination of naringin, hesperidin, neohesperidin, baicalin, wogonoside, baicalein, wogonin, emodin and chrysophanol in ‘Da...In this study, a simple, reliable and accurate method for the simultaneous separation and determination of naringin, hesperidin, neohesperidin, baicalin, wogonoside, baicalein, wogonin, emodin and chrysophanol in ‘Da-Chai-Hu-Tang’ was developed by reverse-phase high-performance liquid chromatography (RP-HPLC). The chromatographic separation was performed on an Agilent ZORBAX C18 column (250 mm × 4.6 mm i.d., 5.0 μm), and the mobile phase composed of methanol and water containing 1% (v/v) acetic acid was used to elute the targets in a gradient elution mode. The flow rate and detection wavelength were set at 0.8 ml/min and 280 nm, respectively. All calibration curves of the nine components expressed good linearities (r2≥0.9992) within the tested ranges. The RSD values demonstrated the intra- and inter-day precisions were less than 2.89%, and the recoveries of the investigated compounds were between 96.22% and 105.28%. The proposed method is simple, precise, specific, sensitive, and successfully applied to determine the nine marker compounds in ‘Da-Chai-Hu-Tang’ for quality control.展开更多
The morphological and structural design provides an efficient protocol to optimize the performance of gas sensing materials.In this work,a gas sensor with high sensitivity for triethylamine(TEA)detection is developed ...The morphological and structural design provides an efficient protocol to optimize the performance of gas sensing materials.In this work,a gas sensor with high sensitivity for triethylamine(TEA)detection is developed based on p-type NiCo2 O4 hierarchical microspheres.The NiCo2 O4 microspheres,synthesized by a hydrothermal route,have a three-dimensional(3 D)urchin-like structure assembled by nanorod building blocks.The structure-property correlation has been investigated by powder X-ray diffraction,X-ray photoelectron spectroscopy,transmission electron microscope,scanning electron microscope,N2 adsorption-desorption tests and comprehensive gas sensing experiments.The influence of calcination temperature on the morphological structure and sensing performances has been investigated.Results reveal that the material annealed at 300℃has a very large specific surface area of 125.27 m2/g,thereby demonstrating the best TEA sensing properties including high response and low limit of detection(145 ppb),good selectivity and stability.The further increase of the calcination temperature leads to the collapse of the 3 D hierarchical structure with significantly decreased surface area,which is found to decline the sensing performances.This work indicates the promise of ternary p-type metal oxide nanostructures for application in highly sensitive gas sensors.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 21601098 and 51602167)Shandong Provincial Science Foundation (ZR2016EMB07 and ZR2017JL021)+1 种基金Key Research and Development Program (2018GGX102033)Qingdao Applied Fundamental Research Project (16-5-1-92-jch and 17-1-1-81-jch)
文摘A strong interface coupling is of vital importance to develop metal oxide/carbon nanocomposite anodes for next-generation lithium ion batteries.Herein,a rational N-doped carb on riveting strategy is designed to boost the lithium storage performance of Fe3O4/N-doped carbon tubular structures.Poly pyrrole(PPy)has been used as the precursor for N-doped carbon.N-doped carbon-riveted Fe3O4/N-doped carbon(N-C@Fe3O4@N-C)nanocomposites were obtained by pyrolysis of PPy-coated FeOOH@PPy nanotubes in Ar atmosphere.When tested as an anode for LIBs,the N-C@Fe3O4@N-C displays a high reversible discharge capacity of 675.8 mA h g-1 after 100 cycles at a current density of 100 mA g-1 and very good rate capability(470 mA h g_1 at 2 A g-1),which significantly surpasses the performance of Fe3O4@N-C.TEM analysis reveals that after battery cycling the FeOx particles detached from the carbon fibers for Fe3O4@N-C,while for N-C@Fe3O4@N-C the FeOx particles were still trapped in the carbon matrix,thus preserving good electrical contact.Consequently,the superior performance of N-C@Fe3C)4@N-C is attributed to the synergistic effect between Fe3O4 and N-doped carbon combined with the unique structure properties of the nanocomposites.The strategy reported in this work is expected to be applicable for designing other electrode materials for LIBs.
文摘In this study, a simple, reliable and accurate method for the simultaneous separation and determination of naringin, hesperidin, neohesperidin, baicalin, wogonoside, baicalein, wogonin, emodin and chrysophanol in ‘Da-Chai-Hu-Tang’ was developed by reverse-phase high-performance liquid chromatography (RP-HPLC). The chromatographic separation was performed on an Agilent ZORBAX C18 column (250 mm × 4.6 mm i.d., 5.0 μm), and the mobile phase composed of methanol and water containing 1% (v/v) acetic acid was used to elute the targets in a gradient elution mode. The flow rate and detection wavelength were set at 0.8 ml/min and 280 nm, respectively. All calibration curves of the nine components expressed good linearities (r2≥0.9992) within the tested ranges. The RSD values demonstrated the intra- and inter-day precisions were less than 2.89%, and the recoveries of the investigated compounds were between 96.22% and 105.28%. The proposed method is simple, precise, specific, sensitive, and successfully applied to determine the nine marker compounds in ‘Da-Chai-Hu-Tang’ for quality control.
基金financially supported by the National Natural Science Foundation of China(Nos.61971252,51972182 and 21601098)Shandong Provincial Science Foundation(Nos.ZR2019BF008 and ZR2017JL021)Key Research and Development Program(No.2018GGX102033)。
文摘The morphological and structural design provides an efficient protocol to optimize the performance of gas sensing materials.In this work,a gas sensor with high sensitivity for triethylamine(TEA)detection is developed based on p-type NiCo2 O4 hierarchical microspheres.The NiCo2 O4 microspheres,synthesized by a hydrothermal route,have a three-dimensional(3 D)urchin-like structure assembled by nanorod building blocks.The structure-property correlation has been investigated by powder X-ray diffraction,X-ray photoelectron spectroscopy,transmission electron microscope,scanning electron microscope,N2 adsorption-desorption tests and comprehensive gas sensing experiments.The influence of calcination temperature on the morphological structure and sensing performances has been investigated.Results reveal that the material annealed at 300℃has a very large specific surface area of 125.27 m2/g,thereby demonstrating the best TEA sensing properties including high response and low limit of detection(145 ppb),good selectivity and stability.The further increase of the calcination temperature leads to the collapse of the 3 D hierarchical structure with significantly decreased surface area,which is found to decline the sensing performances.This work indicates the promise of ternary p-type metal oxide nanostructures for application in highly sensitive gas sensors.
