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2015 Volume 32 Issue 7
2015, 32(7): 733-742
doi: 10.11944/j.issn.1000-0518.2015.07.140441
Abstract:
In recent years,the research of ionic liquids in the extraction of metals has attracted widespread attention and mainly focuses on two aspects,one is hydrophobic ionic liquids as ‘green’ solvent for the extraction of metal ions;the second is task-specific ionic liquid with functional group as extractant for metal ion extraction.The later is the hot-topic area currently.This paper reviewed the research about task-specific ionic liquid extraction and separation of radioactive metals,heavy metals and rare earth metals etc.in recent years,and its future development was prospected.
In recent years,the research of ionic liquids in the extraction of metals has attracted widespread attention and mainly focuses on two aspects,one is hydrophobic ionic liquids as ‘green’ solvent for the extraction of metal ions;the second is task-specific ionic liquid with functional group as extractant for metal ion extraction.The later is the hot-topic area currently.This paper reviewed the research about task-specific ionic liquid extraction and separation of radioactive metals,heavy metals and rare earth metals etc.in recent years,and its future development was prospected.
2015, 32(7): 743-747
doi: 10.11944/j.issn.1000-0518.2015.07.140383
Abstract:
A method for direct asymmetric chlorination of aldehydes and 2,3,4,5,6,6-hexachloro-2,4-cyclohexadien-1-one catalyzed by Pro-Trp in the presence of N-methylmorpholine (NMM) and ionic liquid Zn[CO(NH2)2]3Cl2has been developed.This method produces the corresponding optically active chlorinated products with high yields (up to 95%) and good enantioselectivities (up to 92% ee).The approach has advantages in simple isolation and reusablility of catalyst and ionic liquids.
A method for direct asymmetric chlorination of aldehydes and 2,3,4,5,6,6-hexachloro-2,4-cyclohexadien-1-one catalyzed by Pro-Trp in the presence of N-methylmorpholine (NMM) and ionic liquid Zn[CO(NH2)2]3Cl2has been developed.This method produces the corresponding optically active chlorinated products with high yields (up to 95%) and good enantioselectivities (up to 92% ee).The approach has advantages in simple isolation and reusablility of catalyst and ionic liquids.
2015, 32(7): 748-758
doi: 10.11944/j.issn.1000-0518.2015.07.140421
Abstract:
Sixteen title compounds 1,3,4-thiadiazole derivatives 5a~5p and sixteen intermediates 4a~4p were synthesized using 2-amino-5-substituted-1,3,4-thiadiazoles as the starting materials.All of thirty-two compounds are new compounds.The single crystal of compound 5a was obtained by solution crystallization method.X-ray single crystal diffraction analyses show that the crystal is a triclinic crystal system,P-1 space group.The structures of the title compounds and intermediates were characterized by IR,1H NMR and elemental analyses.The antibacterial activity of compound 5 was evaluated with microdilution method.Compound 5h exhibits higher antibacterial activity to Staphylococcus aureus than the others,of which bacteriostasis rate is up to 65.30%.
Sixteen title compounds 1,3,4-thiadiazole derivatives 5a~5p and sixteen intermediates 4a~4p were synthesized using 2-amino-5-substituted-1,3,4-thiadiazoles as the starting materials.All of thirty-two compounds are new compounds.The single crystal of compound 5a was obtained by solution crystallization method.X-ray single crystal diffraction analyses show that the crystal is a triclinic crystal system,P-1 space group.The structures of the title compounds and intermediates were characterized by IR,1H NMR and elemental analyses.The antibacterial activity of compound 5 was evaluated with microdilution method.Compound 5h exhibits higher antibacterial activity to Staphylococcus aureus than the others,of which bacteriostasis rate is up to 65.30%.
2015, 32(7): 759-764
doi: 10.11944/j.issn.1000-0518.2015.07.140371
Abstract:
Ten dimethyl 2-[(indol-3-yl)-methyl] malomate derivatives were synthesized by three-component one-pot reaction of indole with aldehydes and dimethyl malonate under solvent-free condition in the presence of Sn O as the catalyst.The yields ranged from 58% to 74%.The advantages of this method are no solvent pollution and mild reaction conditions.Furthermore,a mechanism for this condensation reaction was proposed and the relationship between reaction rate and substituent groups was also studied.All the compounds synthesized were confirmed by 1 H NMR,13 C NMR and IR.
Ten dimethyl 2-[(indol-3-yl)-methyl] malomate derivatives were synthesized by three-component one-pot reaction of indole with aldehydes and dimethyl malonate under solvent-free condition in the presence of Sn O as the catalyst.The yields ranged from 58% to 74%.The advantages of this method are no solvent pollution and mild reaction conditions.Furthermore,a mechanism for this condensation reaction was proposed and the relationship between reaction rate and substituent groups was also studied.All the compounds synthesized were confirmed by 1 H NMR,13 C NMR and IR.
2015, 32(7): 765-770
doi: 10.11944/j.issn.1000-0518.2015.07.140400
Abstract:
The main problems in the use and storage of ferrocene derivatives as burning rate catalysts are the migration and volatility of catalysts.A solution for the problems is to introduce polar groups on ferrocene.This paper reported the synthesis of 2-acryloyloxyethyl ferrocenecarboxylate (AEFC) from ferrocenecarboxylic acid (FCA) and 2-hydroxyethyl acrylate (HEA) with N,N'-dicyclohexylcarbodiimide (DCC) as the dehydration agent in the presence of 4-dimethylaminopyridine (DMAP).Under optimized reaction conditions,the synthesis was conducted with FCA,HEA,DMAP,and DCC in a molar ratio of 20:28:20:24 at 0℃ and addition of DCC solution in 60~75 min to give AEFC in 75.1% yield and 98% purity.
The main problems in the use and storage of ferrocene derivatives as burning rate catalysts are the migration and volatility of catalysts.A solution for the problems is to introduce polar groups on ferrocene.This paper reported the synthesis of 2-acryloyloxyethyl ferrocenecarboxylate (AEFC) from ferrocenecarboxylic acid (FCA) and 2-hydroxyethyl acrylate (HEA) with N,N'-dicyclohexylcarbodiimide (DCC) as the dehydration agent in the presence of 4-dimethylaminopyridine (DMAP).Under optimized reaction conditions,the synthesis was conducted with FCA,HEA,DMAP,and DCC in a molar ratio of 20:28:20:24 at 0℃ and addition of DCC solution in 60~75 min to give AEFC in 75.1% yield and 98% purity.
2015, 32(7): 771-776
doi: 10.11944/j.issn.1000-0518.2015.07.140397
Abstract:
Sulfurized isobutylene was prepared from sulfur and isobutylene via high pressure one-step method at 160~190℃ with n-octylamine as catalyst.GC,FT-IR and 1H NMR analyses of the final products show that it contains chain-like and cyclic polysulfides,chain-like polysulfides are main products,accompanied with the byproducts 4-methyl-3H-1,2-dithiole-3-thione (MDTT),tert-butyl mercaptan,and a small amount of exhaust gas such as H2S.The formation of MDTT and H2S is the result of the hydrogen abstraction reaction from isobutylene catalyzed by alkali in the sulfurization process.H2S then reacts with isobutylene by Markovnikov addition to the formation of tert-butyl mercaptan which is converted to linear polysulfides by reaction with sulfur.
Sulfurized isobutylene was prepared from sulfur and isobutylene via high pressure one-step method at 160~190℃ with n-octylamine as catalyst.GC,FT-IR and 1H NMR analyses of the final products show that it contains chain-like and cyclic polysulfides,chain-like polysulfides are main products,accompanied with the byproducts 4-methyl-3H-1,2-dithiole-3-thione (MDTT),tert-butyl mercaptan,and a small amount of exhaust gas such as H2S.The formation of MDTT and H2S is the result of the hydrogen abstraction reaction from isobutylene catalyzed by alkali in the sulfurization process.H2S then reacts with isobutylene by Markovnikov addition to the formation of tert-butyl mercaptan which is converted to linear polysulfides by reaction with sulfur.
2015, 32(7): 777-787
doi: 10.11944/j.issn.1000-0518.2015.07.140408
Abstract:
A novel water-soluble phosphorus-containing tripod ligand[L:N-bis (pyridine-aminoacetyl) methyl phosphate]and its europium complexes was synthesized and characterized by elemental analysis,TG-DSC,IR spectroscopy,UV spectroscopy and molar conductance analysis.In addition,the interaction between bovine serum albumin (BSA) and complexes was investigated with fluorescence spectra at room temperature.The experimental results show that the ligand forms the 1:1 complex Eu (pic)3L with europium picrate.There exists a strong combination action between complexes and BSA.The acting forces between the complexes and BSA are hydrogen bonding and van der Waals interaction.The quenching of BSA by complexes follows the static quenching mechanism.The influence of Fe3+ and Cu2+ on the combination process of the complexes with BSA was investigated.It is found that Fe3+ and Cu2+ can strengthen the interaction of the complex with BSA through the formation a metal bridge bond with the complex.According to Foster type dipole-dipole nonradiative energy transfer mechanism,there is no radiation energy transfer between complexes and BSA by dipole-dipole.
A novel water-soluble phosphorus-containing tripod ligand[L:N-bis (pyridine-aminoacetyl) methyl phosphate]and its europium complexes was synthesized and characterized by elemental analysis,TG-DSC,IR spectroscopy,UV spectroscopy and molar conductance analysis.In addition,the interaction between bovine serum albumin (BSA) and complexes was investigated with fluorescence spectra at room temperature.The experimental results show that the ligand forms the 1:1 complex Eu (pic)3L with europium picrate.There exists a strong combination action between complexes and BSA.The acting forces between the complexes and BSA are hydrogen bonding and van der Waals interaction.The quenching of BSA by complexes follows the static quenching mechanism.The influence of Fe3+ and Cu2+ on the combination process of the complexes with BSA was investigated.It is found that Fe3+ and Cu2+ can strengthen the interaction of the complex with BSA through the formation a metal bridge bond with the complex.According to Foster type dipole-dipole nonradiative energy transfer mechanism,there is no radiation energy transfer between complexes and BSA by dipole-dipole.
2015, 32(7): 788-793
doi: 10.11944/j.issn.1000-0518.2015.07.140390
Abstract:
A series of supported solid-base catalysts (GCK) was prepared by loading KF and Ca O over kaolinite by impregnation.Their activity was investigated for the catalytic transesterification of methyl laurate (ML) with ethylene glycol monomethyl ether (EGME) to produce the novel biodiesel.The catalyst was characterized by X-ray diffraction,scanning electron microscopy and Hammett indicators methods.Moreover,the effect of loading amount of KF and main reaction parameters on the yield of novel biodiesel was examined.The base strength of the GCK (H_value) varies from 7.2 to 18.4.The KCaF3 phase is the main active sites in GCK.The highest yield of novel biodiesel reaches 97.1% under 25% loading of KF over GCK,EGME/ML molar ratio of 3.0,4.5% loading of the catalyst (relative to the ML) and reacting for 2 h at 120℃.At last,the recycle of the catalyst was investigated.
A series of supported solid-base catalysts (GCK) was prepared by loading KF and Ca O over kaolinite by impregnation.Their activity was investigated for the catalytic transesterification of methyl laurate (ML) with ethylene glycol monomethyl ether (EGME) to produce the novel biodiesel.The catalyst was characterized by X-ray diffraction,scanning electron microscopy and Hammett indicators methods.Moreover,the effect of loading amount of KF and main reaction parameters on the yield of novel biodiesel was examined.The base strength of the GCK (H_value) varies from 7.2 to 18.4.The KCaF3 phase is the main active sites in GCK.The highest yield of novel biodiesel reaches 97.1% under 25% loading of KF over GCK,EGME/ML molar ratio of 3.0,4.5% loading of the catalyst (relative to the ML) and reacting for 2 h at 120℃.At last,the recycle of the catalyst was investigated.
2015, 32(7): 794-800
doi: 10.11944/j.issn.1000-0518.2015.07.140414
Abstract:
The products of wheat straw treated with hydrochloric acid,nitric acid,and phosphoric acid were analyzed and the kinetics of production of xylose and furfural during depolymerization were studied.The results show that the products in the depolymerized wheat straw are glucose,xylose,arabinose,acetic acid,cellobiose,furfural,and 5-hydroxymethyl furfural.The rate constants of xylan hydrolysis,xylose conversion and furfural formation at different temperatures were obtained using the modified Saeman model by introducing a variable (α,the ratio of xylose and arabinose).The activation energies of xylose formation with the tested acids (HCl,HNO3,and H3PO4) are 55.5 k J/mol,46.3 k J/mol,and 59.8 k J/mol,respectively.Combined with reaction temperature,time,the reaction rate,and the concentration of xylose and furfural,the optimized acid treatment for wheat straw is HNO3 depolymerization at 130℃ for 95 min.
The products of wheat straw treated with hydrochloric acid,nitric acid,and phosphoric acid were analyzed and the kinetics of production of xylose and furfural during depolymerization were studied.The results show that the products in the depolymerized wheat straw are glucose,xylose,arabinose,acetic acid,cellobiose,furfural,and 5-hydroxymethyl furfural.The rate constants of xylan hydrolysis,xylose conversion and furfural formation at different temperatures were obtained using the modified Saeman model by introducing a variable (α,the ratio of xylose and arabinose).The activation energies of xylose formation with the tested acids (HCl,HNO3,and H3PO4) are 55.5 k J/mol,46.3 k J/mol,and 59.8 k J/mol,respectively.Combined with reaction temperature,time,the reaction rate,and the concentration of xylose and furfural,the optimized acid treatment for wheat straw is HNO3 depolymerization at 130℃ for 95 min.
2015, 32(7): 801-807
doi: 10.11944/j.issn.1000-0518.2015.07.140412
Abstract:
CeO2/TiO2 photocatalyst was synthesized by sol-gel processing and dip-doping technique.Its physicochemical structure and properties were characterized.With pyridine n-octane system as the nitrogen source of simulative oil,the denitrification behavior of this photocatalyst under visible light was studied.The optimal photocatalysis reaction conditions were also explored.The doped cerium component in CeO2 enhances the adsorption of catalyst in the visible light region.When the illumination time is 150 min under visible light,the amount of cerium doped is 8%,the dosage of the CeO2/TiO2 photocatalyst is 1.0 g/L,the denitrification percent of pyridine in the simulative oil reaches up to 76.45%.
CeO2/TiO2 photocatalyst was synthesized by sol-gel processing and dip-doping technique.Its physicochemical structure and properties were characterized.With pyridine n-octane system as the nitrogen source of simulative oil,the denitrification behavior of this photocatalyst under visible light was studied.The optimal photocatalysis reaction conditions were also explored.The doped cerium component in CeO2 enhances the adsorption of catalyst in the visible light region.When the illumination time is 150 min under visible light,the amount of cerium doped is 8%,the dosage of the CeO2/TiO2 photocatalyst is 1.0 g/L,the denitrification percent of pyridine in the simulative oil reaches up to 76.45%.
2015, 32(7): 808-815
doi: 10.11944/j.issn.1000-0518.2015.07.140419
Abstract:
It was found that ionic liquid-like polyoxometalates (IL-POM) functionalized by sulfonic acid possess reversible photochromic properties.Detailed photochromism of [PyPS]nH3-nPW12(n=1,3),[PyPS]4SiW12 and [TEAPS]3PW12 samples were investigated.IL-POMs functionalized by sulfonic acid are a class of salts with weak charge-transfer effect.Under UV irradiation,however,electron interaction between organic cations and POM anions results in the reduction of W6+ to W5+.The formation of a stable chargetransfer complex leads to the coloration.The photochromic ability of tungstophosphate is stronger than that of tungstosilicate.The decoloration occurred in air when the colored sample was placed in dark.But the sample is easily fatigued and a coloration-decoloration cycle with poor reproducibility is observed.A study on photochromic mechanism shows that-SO3H group in organic cation is involved in photochromic process as an electron donor.This reveals the donor property of sulfonic acid and provides a new strategy for designing charge-transfer polyoxometalates and POM-based photochromic materials.
It was found that ionic liquid-like polyoxometalates (IL-POM) functionalized by sulfonic acid possess reversible photochromic properties.Detailed photochromism of [PyPS]nH3-nPW12(n=1,3),[PyPS]4SiW12 and [TEAPS]3PW12 samples were investigated.IL-POMs functionalized by sulfonic acid are a class of salts with weak charge-transfer effect.Under UV irradiation,however,electron interaction between organic cations and POM anions results in the reduction of W6+ to W5+.The formation of a stable chargetransfer complex leads to the coloration.The photochromic ability of tungstophosphate is stronger than that of tungstosilicate.The decoloration occurred in air when the colored sample was placed in dark.But the sample is easily fatigued and a coloration-decoloration cycle with poor reproducibility is observed.A study on photochromic mechanism shows that-SO3H group in organic cation is involved in photochromic process as an electron donor.This reveals the donor property of sulfonic acid and provides a new strategy for designing charge-transfer polyoxometalates and POM-based photochromic materials.
2015, 32(7): 816-824
doi: 10.11944/j.issn.1000-0518.2015.07.140444
Abstract:
A novel type of adsorptive material,dodecylbenzenesulfonate (DBS)-citrate (Cit)-layered double hydroxide (LDHs),DBS-Cit-LDHs,was synthesized by modifying Mg-Al LDHs with both DBS- and citrate3- anions using ion-exchange method.DBS-Cit-LDHs was characterized by powder X-ray diffraction,Fourier transform infrared spectroscopy,low-temperature N2 adsorption,and elemental analysis.The surface property and structure of DBS-Cit-LDHs are significantly altered from Mg-Al LDHs.Batch adsorption experiments indicate that DBS-Cit-LDHs can simultaneously adsorb biphenol A (BPA) and Cu2+ from the mixed solution.The adsorption kinetics of Cu2+ and BPA can be well fitted with the pseudo-second order kinetic model and pseudo-first order kinetic model,respectively.The adsorption isotherm of Cu2+ and BPA can be well fitted with the Freundlich and Linear equations,respectively.BPA adsorption is attributed to a partition retention mechanism.Cu2+ adsorption is dominated by the formation of complexes between Cu2+ and citrate3-anions in the interlayer of DBS-Cit-LDHs.The negative values of ΔGo and ΔHo observed for BPA and Cu2+ adsorption confirm the spontaneity and exothermic nature,respectively.These results indicate the potential application of DBS-Cit-LDHs in treating wastewater containing both organic compounds and heavy metals.
A novel type of adsorptive material,dodecylbenzenesulfonate (DBS)-citrate (Cit)-layered double hydroxide (LDHs),DBS-Cit-LDHs,was synthesized by modifying Mg-Al LDHs with both DBS- and citrate3- anions using ion-exchange method.DBS-Cit-LDHs was characterized by powder X-ray diffraction,Fourier transform infrared spectroscopy,low-temperature N2 adsorption,and elemental analysis.The surface property and structure of DBS-Cit-LDHs are significantly altered from Mg-Al LDHs.Batch adsorption experiments indicate that DBS-Cit-LDHs can simultaneously adsorb biphenol A (BPA) and Cu2+ from the mixed solution.The adsorption kinetics of Cu2+ and BPA can be well fitted with the pseudo-second order kinetic model and pseudo-first order kinetic model,respectively.The adsorption isotherm of Cu2+ and BPA can be well fitted with the Freundlich and Linear equations,respectively.BPA adsorption is attributed to a partition retention mechanism.Cu2+ adsorption is dominated by the formation of complexes between Cu2+ and citrate3-anions in the interlayer of DBS-Cit-LDHs.The negative values of ΔGo and ΔHo observed for BPA and Cu2+ adsorption confirm the spontaneity and exothermic nature,respectively.These results indicate the potential application of DBS-Cit-LDHs in treating wastewater containing both organic compounds and heavy metals.
2015, 32(7): 825-830
doi: 10.11944/j.issn.1000-0518.2015.07.140392
Abstract:
The dry powder of Potamogeton crispus was developed as an efficient biosorbent material for the removal Cr (Ⅵ) from wastewater.The effects of adsorption equilibrium time,grain size of adsorbent particles,initial p H,the dosage of adsorbent,initial concentration of Cr (Ⅵ),and ionic strength on the adsorption performance were investigated by single-factor experiments.The adsorption process follows the pseudo secondorder kinetic with a correlation coefficient (R2) of 0.9998.The experimental data fit with Langmuir isotherm model.The maximum adsorption capacity of Cr (Ⅵ) by Potamogeton crispus is 35.0 mg/g.
The dry powder of Potamogeton crispus was developed as an efficient biosorbent material for the removal Cr (Ⅵ) from wastewater.The effects of adsorption equilibrium time,grain size of adsorbent particles,initial p H,the dosage of adsorbent,initial concentration of Cr (Ⅵ),and ionic strength on the adsorption performance were investigated by single-factor experiments.The adsorption process follows the pseudo secondorder kinetic with a correlation coefficient (R2) of 0.9998.The experimental data fit with Langmuir isotherm model.The maximum adsorption capacity of Cr (Ⅵ) by Potamogeton crispus is 35.0 mg/g.
2015, 32(7): 831-836
doi: 10.11944/j.issn.1000-0518.2015.07.140413
Abstract:
Calcium carbonate with various polymorphs and morphologies was prepared by urea hydrolytic method in this study.The crystals were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis.Uniform needle-like aragonite crystals are obtained in aqueous solution at90℃.In contrast,the addition of sodium citrate results in the formation of novel morphologies of calcite crystals.We also studied the growth of calcium carbonate in the mixed solvent of ethanol/water with sodium citrate as control agent.The results show that sodium citrate also has significant influence on polymorphs and morphologies of calcium carbonate in the ethanol/water mixed solution.Hollow spherical vaterite crystals are obtained in the presence of sodium citrate by changing the volume fraction of ethanol.
Calcium carbonate with various polymorphs and morphologies was prepared by urea hydrolytic method in this study.The crystals were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis.Uniform needle-like aragonite crystals are obtained in aqueous solution at90℃.In contrast,the addition of sodium citrate results in the formation of novel morphologies of calcite crystals.We also studied the growth of calcium carbonate in the mixed solvent of ethanol/water with sodium citrate as control agent.The results show that sodium citrate also has significant influence on polymorphs and morphologies of calcium carbonate in the ethanol/water mixed solution.Hollow spherical vaterite crystals are obtained in the presence of sodium citrate by changing the volume fraction of ethanol.
2015, 32(7): 837-842
doi: 10.11944/j.issn.1000-0518.2015.07.140381
Abstract:
Graphene oxide (GO) and reduced graphene oxide (RGO) were prepared by modified Hummers method and hydrothermal reduction,respectively.They were characterized by transmission electron microscopy (TEM),UV-Vis absorption spectroscopy (UV-Vis),Fourier transform infrared (FTIR) spectroscopy,and photoluminescence emission and excitation spectroscopy (PL,PLE).PL spectra indicate that the broad nearinfrared (NIR) photoluminescence ranging from 600 to 800 nm can be acquired from graphene oxide under excitation of visible light.By comparing PL spectra from GO with that from RGO,and through the analysis of their UV-Vis absorption and FTIR spectra,the oxygen related groups,such as C=O and COOH,are found to be responsible for the NIR PL from GO.NIR fluorescence is favorable for bio-imaging because of its excellent penetrating ability and little damage to tissues.This indictates that GO has great potential applications in bio-imaging.
Graphene oxide (GO) and reduced graphene oxide (RGO) were prepared by modified Hummers method and hydrothermal reduction,respectively.They were characterized by transmission electron microscopy (TEM),UV-Vis absorption spectroscopy (UV-Vis),Fourier transform infrared (FTIR) spectroscopy,and photoluminescence emission and excitation spectroscopy (PL,PLE).PL spectra indicate that the broad nearinfrared (NIR) photoluminescence ranging from 600 to 800 nm can be acquired from graphene oxide under excitation of visible light.By comparing PL spectra from GO with that from RGO,and through the analysis of their UV-Vis absorption and FTIR spectra,the oxygen related groups,such as C=O and COOH,are found to be responsible for the NIR PL from GO.NIR fluorescence is favorable for bio-imaging because of its excellent penetrating ability and little damage to tissues.This indictates that GO has great potential applications in bio-imaging.
2015, 32(7): 843-848
doi: 10.11944/j.issn.1000-0518.2015.07.140404
Abstract:
The flexible MnO2/graphene composite paper electrode for lithium batteries was prepared by electro-deposition of MnO2,via the oxidation of Mn2+ solution,on the graphene film.The paper electrode structure,appearance and electrochemical performances were studied by X-ray diffraction (XRD),scanning electron microscopy (SEM) and transmission electron microscopy (TEM),cyclic voltammetry (CV) and galvanostatic discharging.The results show that spherical MnO2 particles are homogeneously deposited on the graphene flakes to form a MnO2/graphene composite paper electrode with the thickness of 45 μm.The crystal structure of MnO2 in the composite changes from γ-MnO2 to a mixed structure of γ/β-MnO2 after calcination at380℃.The discharge capacity of MnO2 in the composite can reach 269 m A·h/g at 0.1C at room temperature.The structure of graphene is not damaged at the high calcination temperature.The good flexibility,low impendence and excellent electrochemical performance of the MnO2/graphene paper electrode are profitable for flexible Li/MnO2 batteries.
The flexible MnO2/graphene composite paper electrode for lithium batteries was prepared by electro-deposition of MnO2,via the oxidation of Mn2+ solution,on the graphene film.The paper electrode structure,appearance and electrochemical performances were studied by X-ray diffraction (XRD),scanning electron microscopy (SEM) and transmission electron microscopy (TEM),cyclic voltammetry (CV) and galvanostatic discharging.The results show that spherical MnO2 particles are homogeneously deposited on the graphene flakes to form a MnO2/graphene composite paper electrode with the thickness of 45 μm.The crystal structure of MnO2 in the composite changes from γ-MnO2 to a mixed structure of γ/β-MnO2 after calcination at380℃.The discharge capacity of MnO2 in the composite can reach 269 m A·h/g at 0.1C at room temperature.The structure of graphene is not damaged at the high calcination temperature.The good flexibility,low impendence and excellent electrochemical performance of the MnO2/graphene paper electrode are profitable for flexible Li/MnO2 batteries.
2015, 32(7): 849-854
doi: 10.11944/j.issn.1000-0518.2015.07.140401
Abstract:
Horseradish peroxidase (HRP) and carbon nanotubes (CNTs) were co-immobilized on the base electrode surface during the process of potentiostatic electrodeposition of cobalt-aluminium layered double hydroxide (Co Al-LDH).The as-prepared Co Al-LDH-HRP-CNTs modified electrode was used for the determination of hydrogen peroxide.The morphology of Co Al-LDH-HRP-CNTs was characterized by SEM.The preparation process of the modified electrode was monitored by the electrochemical spectroscopy.The electrochemical behavior of the modified electrode was studied by cyclic voltammetry.The effect of p H and work potential on the catalytic reduction performance of the modified electrode was investigated.The biosensor shows a good linear range of 2.5×10-6~3.35×10-4mol/L for the determination of hydrogen peroxide with the sensitivity of 0.0049 A·L/mol.
Horseradish peroxidase (HRP) and carbon nanotubes (CNTs) were co-immobilized on the base electrode surface during the process of potentiostatic electrodeposition of cobalt-aluminium layered double hydroxide (Co Al-LDH).The as-prepared Co Al-LDH-HRP-CNTs modified electrode was used for the determination of hydrogen peroxide.The morphology of Co Al-LDH-HRP-CNTs was characterized by SEM.The preparation process of the modified electrode was monitored by the electrochemical spectroscopy.The electrochemical behavior of the modified electrode was studied by cyclic voltammetry.The effect of p H and work potential on the catalytic reduction performance of the modified electrode was investigated.The biosensor shows a good linear range of 2.5×10-6~3.35×10-4mol/L for the determination of hydrogen peroxide with the sensitivity of 0.0049 A·L/mol.
