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2020 Volume 37 Issue 5
2020, 37(5): 489-501
doi: 10.11944/j.issn.1000-0518.2020.05.190248
Abstract:
Due to its unique surface effects, volume effects and quantum effects, nanomaterials have broad applications in the fields of chemical engineering, bioengineering, medicine, and energy. A number of studies have been carried out using simple low-dimensional nanostructures as the main building blocks to assemble into a regular ordered three-dimensional structure, i.e., hierarchical nanostructures, in a specific arrangement. In this paper, the research progress of hierarchical nanostructures is reviewed. The microstructure of graded nanomaterials and the preparation of graded nanostructures are introduced respectively. The applications of graded nanomaterials in wastewater treatment, supercapacitors, solar cells and photocatalysis are also prospected.
Due to its unique surface effects, volume effects and quantum effects, nanomaterials have broad applications in the fields of chemical engineering, bioengineering, medicine, and energy. A number of studies have been carried out using simple low-dimensional nanostructures as the main building blocks to assemble into a regular ordered three-dimensional structure, i.e., hierarchical nanostructures, in a specific arrangement. In this paper, the research progress of hierarchical nanostructures is reviewed. The microstructure of graded nanomaterials and the preparation of graded nanostructures are introduced respectively. The applications of graded nanomaterials in wastewater treatment, supercapacitors, solar cells and photocatalysis are also prospected.
2020, 37(5): 502-511
doi: 10.11944/j.issn.1000-0518.2020.05.190311
Abstract:
Catalytic amount of organic base triethylamine (Et3N) or inorganic base dipotassium hydrogen phosphate (K2HPO4·3H2O) is proved to effectively promote the three components reaction of aromatic aldehyde, malononitrile and phthalhydrazide under conventional heating conditions. As expected, introduction of water is favorable to the reaction. A series of 1H-pyrazole [1, 2-b]pyridazine-5, 10-diones derivatives was synthesized in the yield of 39%~97%. Both catalysts are soluble in water, and introduction of water also facilitate the separation of the catalyst after reaction. This approach also has advantages of mild reaction conditions, green environmental protection, simple operation and convenient post-treatment.
Catalytic amount of organic base triethylamine (Et3N) or inorganic base dipotassium hydrogen phosphate (K2HPO4·3H2O) is proved to effectively promote the three components reaction of aromatic aldehyde, malononitrile and phthalhydrazide under conventional heating conditions. As expected, introduction of water is favorable to the reaction. A series of 1H-pyrazole [1, 2-b]pyridazine-5, 10-diones derivatives was synthesized in the yield of 39%~97%. Both catalysts are soluble in water, and introduction of water also facilitate the separation of the catalyst after reaction. This approach also has advantages of mild reaction conditions, green environmental protection, simple operation and convenient post-treatment.
2020, 37(5): 512-517
doi: 10.11944/j.issn.1000-0518.2020.05.190287
Abstract:
N-Cyanoethyl-N-hydroxyethylaniline is an important dye intermediate with a wide range of applications. A green and efficient protocol for the synthesis of N-cyanoethyl-N-hydroxyethylaniline by reaction of acrylonitrile and N-hydroxyethyl aniline with 1-butyl-3-methylimidazolium hydrosulphates ionic liquid ([Bmim]HSO4) as the catalyst has been developed, eliminating the inert-gas welding and complex operation of traditional methods. The effect of ionic liquid, the amount of ionic liquid, the ratio of substrates, temperature and time were investigated. The optimum reaction conditions were obtained as follow:[BMIM]HSO4 0.8 mmol, n(N-hydroxyethyl aniline):n(acrylonitrile)=1:1.2, reaction time of 12 h, reaction temperature of 90 ℃. The acdic ionic liquid could be easily separated and reused for at least 5 times without significantly decrease in catalytic activity.
N-Cyanoethyl-N-hydroxyethylaniline is an important dye intermediate with a wide range of applications. A green and efficient protocol for the synthesis of N-cyanoethyl-N-hydroxyethylaniline by reaction of acrylonitrile and N-hydroxyethyl aniline with 1-butyl-3-methylimidazolium hydrosulphates ionic liquid ([Bmim]HSO4) as the catalyst has been developed, eliminating the inert-gas welding and complex operation of traditional methods. The effect of ionic liquid, the amount of ionic liquid, the ratio of substrates, temperature and time were investigated. The optimum reaction conditions were obtained as follow:[BMIM]HSO4 0.8 mmol, n(N-hydroxyethyl aniline):n(acrylonitrile)=1:1.2, reaction time of 12 h, reaction temperature of 90 ℃. The acdic ionic liquid could be easily separated and reused for at least 5 times without significantly decrease in catalytic activity.
2020, 37(5): 518-523
doi: 10.11944/j.issn.1000-0518.2020.05.190361
Abstract:
N-Hydroxyphthalimide (NOP) was used as the radical initiator in the melt graft polymerization of linear low density polyethylene (LLDPE) with four N-halamine precursors, methacrylamide (MA), N-tert-butyl acrylamide (N-t-BuA), maleimide (MI) and 2, 4-diamino-6-diallylamino-1, 3, 5-triazine (NDAM). Meanwhile, the traditional peroxide method was conducted for comparison by using dicumyl peroxide (DCP) as the free radical initiator for melt grafting. The grafting efficiency of the NOP initiator is controlled by the molecular structure and the loading level of the monomer based on the quantitative Fourier transform infrared spectrometer (FT-IR) results. N-t-BuA shows the highest grafting efficiency, which is 2.5%~16.0% lower than that in the DCP system, while MI has the least grafting efficiency, about 55% of the DCP method. However, the crosslink side reaction in the NOP system is more controllable than that in the DCP system, as revealed by the real-time torque, the gel content and the melt index data.
N-Hydroxyphthalimide (NOP) was used as the radical initiator in the melt graft polymerization of linear low density polyethylene (LLDPE) with four N-halamine precursors, methacrylamide (MA), N-tert-butyl acrylamide (N-t-BuA), maleimide (MI) and 2, 4-diamino-6-diallylamino-1, 3, 5-triazine (NDAM). Meanwhile, the traditional peroxide method was conducted for comparison by using dicumyl peroxide (DCP) as the free radical initiator for melt grafting. The grafting efficiency of the NOP initiator is controlled by the molecular structure and the loading level of the monomer based on the quantitative Fourier transform infrared spectrometer (FT-IR) results. N-t-BuA shows the highest grafting efficiency, which is 2.5%~16.0% lower than that in the DCP system, while MI has the least grafting efficiency, about 55% of the DCP method. However, the crosslink side reaction in the NOP system is more controllable than that in the DCP system, as revealed by the real-time torque, the gel content and the melt index data.
2020, 37(5): 524-530
doi: 10.11944/j.issn.1000-0518.2020.05.190346
Abstract:
Functional modification of siliceous earth with γ-aminopropyltriethoxysilane, and functionalized siliceous earth was blended into phenolphthalein-based poly(arylene ether sulfone) (PES-C) to prepare composite materials. And its thermal properties, mechanical properties and barrier properties were characterized and analyzed. The results showed that the surface modification of γ-aminopropyltriethoxy increased the layers' pacing of siliceous earth and made the siliceous earth in the state of semi-stripping, and the doping of the surface modified siliceous earth into PES-C through solution blending was more conducive to the insertion of PES-C molecular chains. The 5% mass loss temperature (T-5%), the T-10% and the Tmax of the composites was increased by 10.2 ℃, 10 ℃ and 3.9 ℃, respectively. In addition, the tensile strength of the composite materials increased by 8.4 MPa, the breaking elongation increased by 2.4%, and the modulus increased by 560.7 MPa. The PO2 of composites was reduced by 77.4%.
Functional modification of siliceous earth with γ-aminopropyltriethoxysilane, and functionalized siliceous earth was blended into phenolphthalein-based poly(arylene ether sulfone) (PES-C) to prepare composite materials. And its thermal properties, mechanical properties and barrier properties were characterized and analyzed. The results showed that the surface modification of γ-aminopropyltriethoxy increased the layers' pacing of siliceous earth and made the siliceous earth in the state of semi-stripping, and the doping of the surface modified siliceous earth into PES-C through solution blending was more conducive to the insertion of PES-C molecular chains. The 5% mass loss temperature (T-5%), the T-10% and the Tmax of the composites was increased by 10.2 ℃, 10 ℃ and 3.9 ℃, respectively. In addition, the tensile strength of the composite materials increased by 8.4 MPa, the breaking elongation increased by 2.4%, and the modulus increased by 560.7 MPa. The PO2 of composites was reduced by 77.4%.
2020, 37(5): 531-540
doi: 10.11944/j.issn.1000-0518.2020.05.190293
Abstract:
The rheological properties of xanthan (XG) /guar gum (GG) mixed solutions and their borax-crosslinked systems were investigated at a total solution concentration of 2.00 g/L. The synergistic interaction viscosification efficiency between XG and GG as well as the influence of solution composition, pH, and electrolytes (NaCl and CaCl2) on the rheological properties were discussed. Under the studied conditions, all solution systems including pure XG, pure GG, and mixed XG/GG solutions as well as their borax-crosslinked systems behave as pseudoplastic fluids, and the rheological curves can be described by the Herschel-Bulkley and Casson models. The mixing of XG and GG exhibits a significant "synergistic viscosification effect". When the mass fraction of XG in the two polymers (w(XG)) is 20% and 90%, maximum values of the synergistic viscosification rate (Rm) are observed, which are 42% and 34%, respectively. The XG/GG mixed solutions can be crosslinked by borax, and the crosslinking effect is enhanced with a decrease in w(XG) or an increase in borax mass concentration (ρ(B)). At w(XG)=50% and ρ(B)=1.00 g/L, the crosslinking viscosification rate (R) is up to 85%. In the studied pH range (6.2~10.0), there is no obvious change in the rheological properties for XG/GG mixed solutions, while for the borax-crosslinked systems (w(XG)=50% and ρ(B)=0.75~1.00 g/L), the apparent viscosity initially increases and then decreases, showing a maximum value at pH=9.0, and the corresponding R is up to ~107%. The addition of electrolytes (NaCl and CaCl2) leads to a significant decrease in the viscosity for the crosslinked XG/GG/B solution (w(XG)=10% and ρ(B)=0.50 g/L), and the influence of CaCl2 is more obvious than that of NaCl. These results may deepen the understanding of rheological behavior of XG/GG mixed solutions and provide important information for their practical applications such as in the enhanced oil recovery.
The rheological properties of xanthan (XG) /guar gum (GG) mixed solutions and their borax-crosslinked systems were investigated at a total solution concentration of 2.00 g/L. The synergistic interaction viscosification efficiency between XG and GG as well as the influence of solution composition, pH, and electrolytes (NaCl and CaCl2) on the rheological properties were discussed. Under the studied conditions, all solution systems including pure XG, pure GG, and mixed XG/GG solutions as well as their borax-crosslinked systems behave as pseudoplastic fluids, and the rheological curves can be described by the Herschel-Bulkley and Casson models. The mixing of XG and GG exhibits a significant "synergistic viscosification effect". When the mass fraction of XG in the two polymers (w(XG)) is 20% and 90%, maximum values of the synergistic viscosification rate (Rm) are observed, which are 42% and 34%, respectively. The XG/GG mixed solutions can be crosslinked by borax, and the crosslinking effect is enhanced with a decrease in w(XG) or an increase in borax mass concentration (ρ(B)). At w(XG)=50% and ρ(B)=1.00 g/L, the crosslinking viscosification rate (R) is up to 85%. In the studied pH range (6.2~10.0), there is no obvious change in the rheological properties for XG/GG mixed solutions, while for the borax-crosslinked systems (w(XG)=50% and ρ(B)=0.75~1.00 g/L), the apparent viscosity initially increases and then decreases, showing a maximum value at pH=9.0, and the corresponding R is up to ~107%. The addition of electrolytes (NaCl and CaCl2) leads to a significant decrease in the viscosity for the crosslinked XG/GG/B solution (w(XG)=10% and ρ(B)=0.50 g/L), and the influence of CaCl2 is more obvious than that of NaCl. These results may deepen the understanding of rheological behavior of XG/GG mixed solutions and provide important information for their practical applications such as in the enhanced oil recovery.
2020, 37(5): 541-546
doi: 10.11944/j.issn.1000-0518.2020.05.190267
Abstract:
In this paper, polyvinyl alcohol/polyaniline/polypyrrole/TiO2(PVA/PANI/PPy/TiO2) hybrid hydrogels were synthesized by the combination of sol-gel technique, in-situ oxidation polymerization and freezing-thawing method with polyvinyl alcohol (PVA), aniline (ANI) and pyrrole (Py) and butyl titanate (TBOT) as raw materials. It is found that the hybrid hydrogel has excellent mechanical properties and electrical conductivity. When n(ANI):n(Py) is 8:2 and the volume of TBOT is 100 μL, the maximum compressive stress of the hybrid hydrogel is 2.45 MPa. Meanwhile, the hybrid hydrogel has good conductivity. Under the action of external electrical source, the bulb could be lighted. When n(ANI):n(Py) is 2:8 and the volume of TBOT is 150 μL, the hybrid hydrogel has the highest conductivity of 0.25 S/m. The hybrid hydrogel is expected to have wide applications in the fields of flexible wearable electronic devices, safe ion batteries, sensors and biological devices.
In this paper, polyvinyl alcohol/polyaniline/polypyrrole/TiO2(PVA/PANI/PPy/TiO2) hybrid hydrogels were synthesized by the combination of sol-gel technique, in-situ oxidation polymerization and freezing-thawing method with polyvinyl alcohol (PVA), aniline (ANI) and pyrrole (Py) and butyl titanate (TBOT) as raw materials. It is found that the hybrid hydrogel has excellent mechanical properties and electrical conductivity. When n(ANI):n(Py) is 8:2 and the volume of TBOT is 100 μL, the maximum compressive stress of the hybrid hydrogel is 2.45 MPa. Meanwhile, the hybrid hydrogel has good conductivity. Under the action of external electrical source, the bulb could be lighted. When n(ANI):n(Py) is 2:8 and the volume of TBOT is 150 μL, the hybrid hydrogel has the highest conductivity of 0.25 S/m. The hybrid hydrogel is expected to have wide applications in the fields of flexible wearable electronic devices, safe ion batteries, sensors and biological devices.
2020, 37(5): 547-554
doi: 10.11944/j.issn.1000-0518.2020.05.190327
Abstract:
A cellulose gel electrolyte (XWD-NaOH) was obtained through static hydration and crosslinking of cellulose pulp viscose solution, followed by introducing potassium ferrocyanide into XWD-NaOH to give a gel electrolyte (XWD-NaOH-K4[Fe(CN)6]). XWD-NaOH-K4[Fe(CN)6] has excellent redox activity and ionic conductivity (15.3 mS/cm). At 0.5 A/g current density, XWD-NaOH-K4[Fe(CN)6] electrolyte supercapacitor exhibits an increase of the electrode specific capacitance, power density and energy density by 57%, 111% and 214% compared to those of XWD-NaOH system. The XWD-NaOH-K4[Fe(CN)6] system has low internal resistance, charge transfer resistance and high cycle stability
A cellulose gel electrolyte (XWD-NaOH) was obtained through static hydration and crosslinking of cellulose pulp viscose solution, followed by introducing potassium ferrocyanide into XWD-NaOH to give a gel electrolyte (XWD-NaOH-K4[Fe(CN)6]). XWD-NaOH-K4[Fe(CN)6] has excellent redox activity and ionic conductivity (15.3 mS/cm). At 0.5 A/g current density, XWD-NaOH-K4[Fe(CN)6] electrolyte supercapacitor exhibits an increase of the electrode specific capacitance, power density and energy density by 57%, 111% and 214% compared to those of XWD-NaOH system. The XWD-NaOH-K4[Fe(CN)6] system has low internal resistance, charge transfer resistance and high cycle stability
2020, 37(5): 555-561
doi: 10.11944/j.issn.1000-0518.2020.05.190304
Abstract:
Flexible lithium-ion batteries with high-performance play a significant role in the development of wearable electronics. Pyrrole was polymerized in situ on polyethylene terephthalate (PET) non-woven fabric substrate through chemical oxidation method. By controlling the reaction conditions, PET-based polypyrrole(PPy) flexible electrode (PPy/PET) with different morphologies can be obtained. When the shearing force is low, the morphology of resulting PPy was nanowires (NW), vice versa, nanoparticles (NP). The mean diameter of PPy-NW is 460 nm. PET is covered with the interconnected PPy-NW, forming three-dimensional netlike conducting pathways. The as-prepared samples are directly used as binder-free flexible electrodes. The results of electrochemical tests demonstrate that PPy-NW/PET is favorable for enhancing lithium storage performance. It delivers an initial discharge and charge capacity of 124 and 98 mA·h/g with superior flexibility and stability. This paper offers a strategy for the fabrication of flexible and lightweight electrode materials and their application in energy storage.
Flexible lithium-ion batteries with high-performance play a significant role in the development of wearable electronics. Pyrrole was polymerized in situ on polyethylene terephthalate (PET) non-woven fabric substrate through chemical oxidation method. By controlling the reaction conditions, PET-based polypyrrole(PPy) flexible electrode (PPy/PET) with different morphologies can be obtained. When the shearing force is low, the morphology of resulting PPy was nanowires (NW), vice versa, nanoparticles (NP). The mean diameter of PPy-NW is 460 nm. PET is covered with the interconnected PPy-NW, forming three-dimensional netlike conducting pathways. The as-prepared samples are directly used as binder-free flexible electrodes. The results of electrochemical tests demonstrate that PPy-NW/PET is favorable for enhancing lithium storage performance. It delivers an initial discharge and charge capacity of 124 and 98 mA·h/g with superior flexibility and stability. This paper offers a strategy for the fabrication of flexible and lightweight electrode materials and their application in energy storage.
2020, 37(5): 562-569
doi: 10.11944/j.issn.1000-0518.2020.05.190306
Abstract:
Silicon/carbon (Si/C/C) composites based on the coal pitch was successfully prepared by a two-step method. Commercially available nano-silicon and coal pitch with low softening point, high carbon ratio and low price were used as the silicon and carbon sources, respectively. The electrochemical properties of the as-obtained composites as the negative electrode of the lithium ion batteries were systematically investigated. The results show that the obtained composite has a particle size in the range of 300 to 350 nm. The Si nanoparticles coated with C are bonded to each other to form a C-Si-C network structure, in which the silicon(27% mass fraction)/carbon composite (Si/C/C-27%) exhibits good lithium storage performance as a lithium battery electrode material. In addition, the Si/C/C-27% composite has a specific discharge capacity of 1281 mA·h/g at a current density of 0.1 A/g; at a current density of 3 A/g, the composite has a specific discharge capacity of 582 mA·h/g, showing good rate performance. The cycle efficiency retention of the product is 76.61% after 100 cycling times at the current density of 2 A/g, which also demonstrates its high stability. Compared with the one-step carbon-coated silicon(Si/C) material, Si/C/C material not only effectively improves the conductivity but inhibits the volume expansion of Si particles during lithiation and de-lithiation. This new proposed method provides a new research idea for preparing lithium ion battery anode materials with excellent electrochemical performance.
Silicon/carbon (Si/C/C) composites based on the coal pitch was successfully prepared by a two-step method. Commercially available nano-silicon and coal pitch with low softening point, high carbon ratio and low price were used as the silicon and carbon sources, respectively. The electrochemical properties of the as-obtained composites as the negative electrode of the lithium ion batteries were systematically investigated. The results show that the obtained composite has a particle size in the range of 300 to 350 nm. The Si nanoparticles coated with C are bonded to each other to form a C-Si-C network structure, in which the silicon(27% mass fraction)/carbon composite (Si/C/C-27%) exhibits good lithium storage performance as a lithium battery electrode material. In addition, the Si/C/C-27% composite has a specific discharge capacity of 1281 mA·h/g at a current density of 0.1 A/g; at a current density of 3 A/g, the composite has a specific discharge capacity of 582 mA·h/g, showing good rate performance. The cycle efficiency retention of the product is 76.61% after 100 cycling times at the current density of 2 A/g, which also demonstrates its high stability. Compared with the one-step carbon-coated silicon(Si/C) material, Si/C/C material not only effectively improves the conductivity but inhibits the volume expansion of Si particles during lithiation and de-lithiation. This new proposed method provides a new research idea for preparing lithium ion battery anode materials with excellent electrochemical performance.
2020, 37(5): 570-578
doi: 10.11944/j.issn.1000-0518.2020.05.190280
Abstract:
Ternary Ho3+-TiO2/Bi plasmonic composite fibers were prepared via hydrothermal method employing electrospun Ho3+-TiO2 nanofibers as the substrate. The composition, morphology and photoelectric properties of the composite fibers were characterized by X-ray diffraction (XRD), X-ray photoelectric spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflection spectrum (UV-Vis DRS) and instantaneous photocurrent. The photocatalytic water splitting for hydrogen evolution was investigated over Ho3+-TiO2/Bi plasmonic composite fibers with triethanolamine as the donor residue. The results showed that Bi nanoparticles formed via reduction of Bi3+ by sodium gluconate during hydrothermal process, meanwhile the heterojunction grew on the Ho3+-TiO2 nanofibers surface. The enhanced photocatalytic activity of the Ho3+-TiO2/Bi plasmonic composites fibers can be further improved, which was mainly attributed to the formation of high-quality heterojunctions between Bi and rare earth Ho3+ doped titanium dioxide. Modification of TiO2 nanofibers effectively improved the photocatalytic activity and stability of the samples under visible light. The highest hydrogen production rate was 43.6 μmol/(g·h).
Ternary Ho3+-TiO2/Bi plasmonic composite fibers were prepared via hydrothermal method employing electrospun Ho3+-TiO2 nanofibers as the substrate. The composition, morphology and photoelectric properties of the composite fibers were characterized by X-ray diffraction (XRD), X-ray photoelectric spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflection spectrum (UV-Vis DRS) and instantaneous photocurrent. The photocatalytic water splitting for hydrogen evolution was investigated over Ho3+-TiO2/Bi plasmonic composite fibers with triethanolamine as the donor residue. The results showed that Bi nanoparticles formed via reduction of Bi3+ by sodium gluconate during hydrothermal process, meanwhile the heterojunction grew on the Ho3+-TiO2 nanofibers surface. The enhanced photocatalytic activity of the Ho3+-TiO2/Bi plasmonic composites fibers can be further improved, which was mainly attributed to the formation of high-quality heterojunctions between Bi and rare earth Ho3+ doped titanium dioxide. Modification of TiO2 nanofibers effectively improved the photocatalytic activity and stability of the samples under visible light. The highest hydrogen production rate was 43.6 μmol/(g·h).
2020, 37(5): 579-586
doi: 10.11944/j.issn.1000-0518.2020.05.190315
Abstract:
In this work, the flake nickel cobalt hydroxide was successfully prepared by the chemical co-precipitation method, and the effect of nickel to cobalt molar ratios on the morphologies and electrochemical properties were explored. The structures and morphologies of samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscope (XPS) and specific surface area and pore size analyzer (BET). The electrochemical properties were analyzed by cyclic voltammetry, galvanostatic charge/discharge, etc. The results show that when nickel cobalt hydroxide (n(Ni):n(Co)=4:1) is directly used as electrode material, it has a high specific capacitance of 1852 F/g at a current density of 0.5 A/g. When the current density is increased by 20 times, it still has a high specific capacitance of 1330 F/g. The asymmetric supercapacitor is assembled with nickel cobalt hydroxide as the positive electrode material and active carbon as the negative electrode material. The asymmetric cell possesses a high energy density of 52 Wh/kg at a power density of 346 W/kg, and superior cycle stability (the capacitance retention of 92% after 10000 cycles). Excellent electrochemical properties indicate that flake nickel cobalt hydroxide is one of the most promising electrode materials.
In this work, the flake nickel cobalt hydroxide was successfully prepared by the chemical co-precipitation method, and the effect of nickel to cobalt molar ratios on the morphologies and electrochemical properties were explored. The structures and morphologies of samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscope (XPS) and specific surface area and pore size analyzer (BET). The electrochemical properties were analyzed by cyclic voltammetry, galvanostatic charge/discharge, etc. The results show that when nickel cobalt hydroxide (n(Ni):n(Co)=4:1) is directly used as electrode material, it has a high specific capacitance of 1852 F/g at a current density of 0.5 A/g. When the current density is increased by 20 times, it still has a high specific capacitance of 1330 F/g. The asymmetric supercapacitor is assembled with nickel cobalt hydroxide as the positive electrode material and active carbon as the negative electrode material. The asymmetric cell possesses a high energy density of 52 Wh/kg at a power density of 346 W/kg, and superior cycle stability (the capacitance retention of 92% after 10000 cycles). Excellent electrochemical properties indicate that flake nickel cobalt hydroxide is one of the most promising electrode materials.
2020, 37(5): 587-594
doi: 10.11944/j.issn.1000-0518.2020.05.190312
Abstract:
We reported a direct one-pot approach, employing 2-mercaptobenzimidazole as a protective agent, polyvinyl pyrrolidone as a stabilizer and hydrazine hydrate as a reducing agent, for rapid preparation of highly stable, strong fluorescent, large Stokes shift fluorescent copper nanoclusters (Cu NCs) from Cu(NO3)2 in aqueous solution at room temperature. Meanwhile, we studied the possibility of the Cu NCs to detect silver ion in water samples. The structure of Cu NCs was characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The optical performance was studied using fluorescence spectroscopy and UV-visible absorption spectroscopy. The as-prepared Cu NCs exhibit a fluorescence emission at 559 nm, and show colorless and orange fluorescence under sunlight and UV light irradiation, respectively. The Cu NCs were highly dispersed with the size of 2~3 nm. In addition, it exhibits good water solubility, excellent photostability and high stability toward high concentration of sodium chloride. Under optimal reaction conditions, the Cu NCs can be used for the highly sensitive and selective detection of silver ions (Ag+) in aqueous solution. The fluorescence intensity quenches linearly within the range of 1 to 40 μmol/L with high sensitivity (LOD=0.5 μmol/L, S/N=3) and this sensing system has been successfully applied for environmental water sample analysis.
We reported a direct one-pot approach, employing 2-mercaptobenzimidazole as a protective agent, polyvinyl pyrrolidone as a stabilizer and hydrazine hydrate as a reducing agent, for rapid preparation of highly stable, strong fluorescent, large Stokes shift fluorescent copper nanoclusters (Cu NCs) from Cu(NO3)2 in aqueous solution at room temperature. Meanwhile, we studied the possibility of the Cu NCs to detect silver ion in water samples. The structure of Cu NCs was characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The optical performance was studied using fluorescence spectroscopy and UV-visible absorption spectroscopy. The as-prepared Cu NCs exhibit a fluorescence emission at 559 nm, and show colorless and orange fluorescence under sunlight and UV light irradiation, respectively. The Cu NCs were highly dispersed with the size of 2~3 nm. In addition, it exhibits good water solubility, excellent photostability and high stability toward high concentration of sodium chloride. Under optimal reaction conditions, the Cu NCs can be used for the highly sensitive and selective detection of silver ions (Ag+) in aqueous solution. The fluorescence intensity quenches linearly within the range of 1 to 40 μmol/L with high sensitivity (LOD=0.5 μmol/L, S/N=3) and this sensing system has been successfully applied for environmental water sample analysis.
2020, 37(5): 595-603
doi: 10.11944/j.issn.1000-0518.2020.05.190299
Abstract:
Polyacrylamide@graphene oxide/nano-palladium composite was prepared on the surface of gold electrode (Au/PAM@GO/Pd) by metal-free visible light-induced atom transfer radical polymerization (MVL ATRP). The Au/PAM@GO/Pd electrode was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that the composite is successfully prepared on the surface of the gold electrode. The Au/PAM@GO/Pd electrode could be used as an electrochemical sensor to detect ethanol by differential pulse voltammetry (DPV). Under the optimal conditions, the linear range is 1.0×10-8~1.0 mol/L, and the detection limit (S/N=3) is 1.3×10-9 mol/ L, with a coefficient of 0.996.
Polyacrylamide@graphene oxide/nano-palladium composite was prepared on the surface of gold electrode (Au/PAM@GO/Pd) by metal-free visible light-induced atom transfer radical polymerization (MVL ATRP). The Au/PAM@GO/Pd electrode was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that the composite is successfully prepared on the surface of the gold electrode. The Au/PAM@GO/Pd electrode could be used as an electrochemical sensor to detect ethanol by differential pulse voltammetry (DPV). Under the optimal conditions, the linear range is 1.0×10-8~1.0 mol/L, and the detection limit (S/N=3) is 1.3×10-9 mol/ L, with a coefficient of 0.996.
2020, 37(5): 604-610
doi: 10.11944/j.issn.1000-0518.2020.05.190303
Abstract:
In this paper, the interaction between thiourea aryl iridium and bovine serum albumin (BSA) was studied by ultraviolet-visible spectroscopy (UV-Vis) and fluorescence spectroscopy under physiological conditions. The mechanism of action was determined, the type of binding force was discussed, and the activation energy of the reaction of thiourea aryl iridium anticancer compound with bovine serum albumin was calculated. The experimental results show that m-methoxybenzaldehyde 4-phenyl-3-thiourea aryl iridium (TSC-Ir-6) complex has a quenching effect on endogenous fluorescence of bovine serum albumin, and the quenching type is static quenching. Through the fixed Stern-Volmer equations and apparent binding constant, the thermodynamic parameters calculated by the formula, it is concluded that the combination of TSC-Ir-6 and BSA is a spontaneous process (ΔG < 0), and the interaction forces are hydrogen bonding and van der Waals force. The number of binding sites is about one. With the presence of coexisting ions, the binding constant between TSC-Ir-6 and BSA is significantly increased, the binding force is stronger, and the retention time of TSC-Ir-6 in plasma is improved, which may lead to a better therapeutic effect.
In this paper, the interaction between thiourea aryl iridium and bovine serum albumin (BSA) was studied by ultraviolet-visible spectroscopy (UV-Vis) and fluorescence spectroscopy under physiological conditions. The mechanism of action was determined, the type of binding force was discussed, and the activation energy of the reaction of thiourea aryl iridium anticancer compound with bovine serum albumin was calculated. The experimental results show that m-methoxybenzaldehyde 4-phenyl-3-thiourea aryl iridium (TSC-Ir-6) complex has a quenching effect on endogenous fluorescence of bovine serum albumin, and the quenching type is static quenching. Through the fixed Stern-Volmer equations and apparent binding constant, the thermodynamic parameters calculated by the formula, it is concluded that the combination of TSC-Ir-6 and BSA is a spontaneous process (ΔG < 0), and the interaction forces are hydrogen bonding and van der Waals force. The number of binding sites is about one. With the presence of coexisting ions, the binding constant between TSC-Ir-6 and BSA is significantly increased, the binding force is stronger, and the retention time of TSC-Ir-6 in plasma is improved, which may lead to a better therapeutic effect.
