Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was inves...Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.展开更多
A novel bimetallic Ni/Co-based metal-organic framework(Ni/Co-MOF) was successfully synthesized via a simple solvothermal method, and used as electrode material for high performance supercapacitors. After doping of Co ...A novel bimetallic Ni/Co-based metal-organic framework(Ni/Co-MOF) was successfully synthesized via a simple solvothermal method, and used as electrode material for high performance supercapacitors. After doping of Co element, the Ni/Co-MOF materials retain the original crystalline topology structure of Ni_3(BTC)_2·12H_2O.The as-obtained Ni/Co-MOF demonstrates an excellent specific capacitance of 1067 and 780 F/g at current density of 1 and 10 A/g, respectively, and can also retain 68.4% of the original capacitance after 2500 cycles. These results suggest that bimetallic Ni/Co-based MOFs are promising materials for the next generation supercapacitance,owing to their excellent electrochemical performance. The synthetic procedure can be applied to synthesize other bimetallic MOFs and enhance their conductive property.展开更多
To reduce microsegregation,a series of homogenization treatments were carried out on a Ni-Co based superalloy prepared through directional solidification(DS).The element segregation characteristics and microstructural...To reduce microsegregation,a series of homogenization treatments were carried out on a Ni-Co based superalloy prepared through directional solidification(DS).The element segregation characteristics and microstructural evolution were investigated by optical microscopy(OM),scanning electron microscopy(SEM),and electron probe microanalysis(EPMA).The results show that the elements are non-uniformly distributed in the solidified superalloy,in which W and Ti have the greatest tendency of microsegregation.Furthermore,severe microsegregation leads to complicated precipitations,includingη-Ni_(3) Ti and eutectic(γ+γ’).EPMA results show that Al and Mo are uniformly distributed between the eutectic(γ+γ’)andγmatrix,whereas Ti is segregated in the eutectic(γ+γ’)andηphases.The positive segregation element Ti,which is continuously rejected into the remaining liquid duringγmatrix solidification,promotes the formation of eutectic(γ+γ’)and the transformation of theηphase.According to the homogenization effect,the optimal single-stage homogenization process of this alloy is 1180℃for 2 h because of the sufficient diffusion segregation of the elements.In the present study,a kinetic diffusion model was built to reflect the degree of element segregation during homogenization,and the diffusion coefficients of W and Ti were estimated.展开更多
Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficien...Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficient nonprecious metal catalysts.Herein,we report for the first time of a facile synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst.The resultant Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100%conversion efficiency and selectivity under mild reaction conditions,surpassing the reported high performance nonprecious HDO catalysts.Impressively,our experimental results also unveil that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100%conversion efficiency and over 90%selectivity.Importantly,our DFT calculations and experimental results confirm that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O,and desorption of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs.The findings of this work affords a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.展开更多
Non Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated w ith an aim of finding high electrocatalytic surface property for the faster electrode reactions.Electrodes w...Non Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated w ith an aim of finding high electrocatalytic surface property for the faster electrode reactions.Electrodes w ere fabricated by electrodeposition on pure Al foil,from an electrolyte of Ni,Co,Fe salts.The optimum condition of electrodeposition w ere found out by a series of experiments,varying the chemistry of the electrolyte,pH valve,temperature,current and cell potential.Polarization study of the coated Ni-Co or Ni-CoFe alloy on pure Al w as found to exhibit high exchange current density,indicating an improved electro catalytic surface w ith faster charge-discharge reactions at anode and cathode and low overvoltage.Electrochemical impedance studies on coated and uncoated surface clearly show ed that the polarization resistance and impedance w ere decreased by Ni-Co or Ni-Co-Fe coating.X-ray diffraction(XRD),energy dispersive X-ray spectroscopy(EDX)and atomic absorption spectroscopy(AAS)studies confirmed the presence of alloying elements and constituents of the alloy.The morphology of the deposits from scanning electron microscope(SEM)images indicated that the electrode surface w as a three dimensional space w hich increased the effective surface area for the electrode reactions to take place.展开更多
A novel precursor of nickel-cobalt alloy powders with an appropriate Ni to Co molar ratio was prepared under selectively synthetic conditions. The composition and morphology of the precursor were characterized by X-ra...A novel precursor of nickel-cobalt alloy powders with an appropriate Ni to Co molar ratio was prepared under selectively synthetic conditions. The composition and morphology of the precursor were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectrometry （FT-IR） and energy dispersive spectrometry （EDS）. The effects of pH value, reaction temperature, metal ion concentrations and surfactant on the morphology and the dispersion of precursor were investigated. The results show that the morphology of precursor depends on ammonia content in the precursor. A fibriform precursor is a complicated ammonia-containing nickel-cobalt oxalate. The uniform shape-controlled fibrous precursor is obtained under the following optimum conditions： ammonia as complex agent as well as pH adjustor, oxalate as coprecipitator, 50-65 °C of reaction temperature, 0.5-0.8 mol/L of total concentration of Ni2＋ and Co2＋, PVP as dispersant, and pH 8.0-8.4.展开更多
In order to obtain more accurate density for molten Ni-(Cr,Co,W)binary alloy,the densities of molten pure Ni and Ni-Cr,Ni-Co,Ni-W alloys were measured with a sessile drop method.It is found that the measured densities...In order to obtain more accurate density for molten Ni-(Cr,Co,W)binary alloy,the densities of molten pure Ni and Ni-Cr,Ni-Co,Ni-W alloys were measured with a sessile drop method.It is found that the measured densities of molten pure Ni and Ni-Cr,Ni-Co,Ni-W alloys decrease with increasing temperature in the experimental temperature range.The density of alloys increases with increasing W and Co concentrations while it decreases with increasing Cr concentration in the alloy at 1 773-1 873 K.The molar volume of Ni-based alloys increases with increasing W concentration while it decreases with increasing Co concentration.The effect of Cr concentration on the molar volume of the alloy is little in the studied concentration range.The accommodation among atomic species was analyzed.The deviation of molar volume from ideal mixing shows an ideal mixing of Ni-(Cr,Co,W)binary alloys.展开更多
Bimetallic catalysts(Ni-Co/AC and Ni-Fe/AC)supported on activated carbon(AC)were prepared via one-step method from coal as AC precursor with the addition of metal salts by KOH activation.The effects of the introductio...Bimetallic catalysts(Ni-Co/AC and Ni-Fe/AC)supported on activated carbon(AC)were prepared via one-step method from coal as AC precursor with the addition of metal salts by KOH activation.The effects of the introduction of second metal(Co or Fe)into Ni/AC on the textural structure of the resultant bimetallic catalysts and their catalytic performances for methane decomposition were investigated.The results showed that active metals can be directly supported on AC by the reaction of metal species with carbon during the activation.The addition of Co or Fe to Ni/AC resulted in the decrease of specific surface area and pore volume.With increasing the loading of Co or Fe,metal alloys were formed and total surface area and pore volume declined,but the mesoporosity was increased.Bimetallic Ni-Co/AC and Ni-Fe/AC catalysts exhibited better catalytic activity and stability for methane decomposition compared than Ni/AC.The introduction of Co mainly improved initial catalytic activity;however,Ni-Fe/AC catalyst showed better behaviors in terms of reducing the deactivation rate of Ni-based catalyst than Ni-Co/AC catalyst,which is relative with the formation of Ni-Fe alloy and carbon fibers over Ni-Fe/AC.This work provides a simple and efficient approach to improve catalytic performances of Ni-based catalyst for methane decomposition.展开更多
Comprehensive Summary A novel electrocatalyst,Ni-Co/β-Mo2C@C,was rationally designed to enhance the efficiency of the hydrogen evolution reaction(HER)in this work.Assembled with two-dimensional Ni-Co nanosheets onto ...Comprehensive Summary A novel electrocatalyst,Ni-Co/β-Mo2C@C,was rationally designed to enhance the efficiency of the hydrogen evolution reaction(HER)in this work.Assembled with two-dimensional Ni-Co nanosheets onto Mo2C nanorods coated with a thin carbon shell,the catalyst demonstrates remarkable performance,including low overpotential(η10=57 mV)and reduced Tafel slope(63 mV·dec^(–1))in 0.5 mol·L^(–1)H2SO4 electrolyte.This innovative design strategy provides abundant active sites and efficient electron/ion transport pathways,effectively shortening reactant diffusion distances and enhancing electrocatalytic activity.Additionally,the carbon shell coating protects the catalyst from etching and agglomeration,ensuring its durability.This work presents a promising approach for engineering highly efficient metal carbide-based HER catalysts through tailored composition and nanostructure design.展开更多
通过在镍钴双金属氢氧化物(Ni-Co LDH)的合成体系中引入胺修饰板钛矿TiO2得到了Ni-Co LDH/TiO2复合光催化材料,并对其光催化降解环丙沙星(CIP)抗生素的活性进行了研究。扫描电子显微镜(SEM)显示Ni-Co LDH将棒状的板钛矿TiO2完全包裹,增...通过在镍钴双金属氢氧化物(Ni-Co LDH)的合成体系中引入胺修饰板钛矿TiO2得到了Ni-Co LDH/TiO2复合光催化材料,并对其光催化降解环丙沙星(CIP)抗生素的活性进行了研究。扫描电子显微镜(SEM)显示Ni-Co LDH将棒状的板钛矿TiO2完全包裹,增大了材料与环丙沙星分子的接触面积。当TiO2与LDH的摩尔比为1:4时,复合材料表现出最佳的催化活性且Ni-Co LDH/TiO2(1:4)在四次循环实验后仍未出现明显的活性下降,说明其具有优异的稳定性。光电化学结果证明这种结构为光催化环丙沙星降解提供了更多的活性位点,其优异的光生电子与空穴的分离和传输效率是其具有最佳催化活性的主要原因。Ni-Co LDH/brookite TiO2 composite is prepared by adding amine-modified TiO2 into the fabrication system of Ni-Co layered bimetallic hydroxide (Ni-Co LDH), and its photocatalytic degradation of ciprofloxacin (CIP) antibiotic is studied. Scanning electron microscopy (SEM) images show that Ni-Co LDH wrapped on the brookite TiO2 increases the contact area between the catalyst and ciprofloxacin molecules. It is found that when the mole ratio of TiO2 to Ni-Co LDH is 1:4, the composite exhibits the best catalytic activity, and the activity of Ni-Co LDH/TiO2(1:4) has no decrease significantly after four cycles tests, indicating that it has excellent stability. The photochemical results show that this structure provides more active sites for photocatalytic ciprofloxacin degradation, and its excellent separation and transfer efficiency of photogenerated electrons and holes are the main reason for its optimal catalytic activity.展开更多
The urgent need of high-performance of energy storage devices triggers us to design newly class of materials.Generally,the materials feature with high conductivity,abundant pore s and excellent stability.Here,a sandwi...The urgent need of high-performance of energy storage devices triggers us to design newly class of materials.Generally,the materials feature with high conductivity,abundant pore s and excellent stability.Here,a sandwiched hybrid composite containing reduced graphene oxide,polypyrrole and Ni-Co layered double hydroxides(RGO/PPy/NiCo-LDH) was prepared in a facile way.The polypyrrole was incorporated in the two dimensional(2D) nanosheets,which not only serve as the spacer to increase the surface area,but also enhance the conductivity of the nanocomposite.The obtained architecture was employed as an advanced electrode in a supercapacitor.The electrode shows an ultrahigh specific capacitance(2534 F g^-1 at 1 A g^-1) and good cycling efficiency(78 % after 5000 cycles).Moreover,an asymmetric cell based RGO/PPy/NiCo-LDH composite demonstrates excellent electrochemical properties and good prospect of practical use.展开更多
基金supported by the National Natural Science Foundation of China(11075113)
文摘Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.
基金financially supported by the National Natural Science Foundation of China(Nos. 21306026, 21576054, 51678160)the Scientific Project of Guangdong Province(Nos. 2014A010106030,2014A010105041,2016A010104017, 2016B020241003)the Foundation of Higher Education of Guangdong Province(No. 2015KTSCX027)
文摘A novel bimetallic Ni/Co-based metal-organic framework(Ni/Co-MOF) was successfully synthesized via a simple solvothermal method, and used as electrode material for high performance supercapacitors. After doping of Co element, the Ni/Co-MOF materials retain the original crystalline topology structure of Ni_3(BTC)_2·12H_2O.The as-obtained Ni/Co-MOF demonstrates an excellent specific capacitance of 1067 and 780 F/g at current density of 1 and 10 A/g, respectively, and can also retain 68.4% of the original capacitance after 2500 cycles. These results suggest that bimetallic Ni/Co-based MOFs are promising materials for the next generation supercapacitance,owing to their excellent electrochemical performance. The synthetic procedure can be applied to synthesize other bimetallic MOFs and enhance their conductive property.
基金financially supported by the National Key R&D Program of China(Nos.2019YFA0705304 and 2017YFA0700703)the National Natural Science Foundation of China(No.51671189)+1 种基金Innovation Program of Institute of Metal Research,China Academy of Science(No.2021-PY09)the Doctoral Scientific Research Foundation of Liaoning Province(No.2020-BS-007)。
文摘To reduce microsegregation,a series of homogenization treatments were carried out on a Ni-Co based superalloy prepared through directional solidification(DS).The element segregation characteristics and microstructural evolution were investigated by optical microscopy(OM),scanning electron microscopy(SEM),and electron probe microanalysis(EPMA).The results show that the elements are non-uniformly distributed in the solidified superalloy,in which W and Ti have the greatest tendency of microsegregation.Furthermore,severe microsegregation leads to complicated precipitations,includingη-Ni_(3) Ti and eutectic(γ+γ’).EPMA results show that Al and Mo are uniformly distributed between the eutectic(γ+γ’)andγmatrix,whereas Ti is segregated in the eutectic(γ+γ’)andηphases.The positive segregation element Ti,which is continuously rejected into the remaining liquid duringγmatrix solidification,promotes the formation of eutectic(γ+γ’)and the transformation of theηphase.According to the homogenization effect,the optimal single-stage homogenization process of this alloy is 1180℃for 2 h because of the sufficient diffusion segregation of the elements.In the present study,a kinetic diffusion model was built to reflect the degree of element segregation during homogenization,and the diffusion coefficients of W and Ti were estimated.
文摘Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficient nonprecious metal catalysts.Herein,we report for the first time of a facile synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst.The resultant Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100%conversion efficiency and selectivity under mild reaction conditions,surpassing the reported high performance nonprecious HDO catalysts.Impressively,our experimental results also unveil that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100%conversion efficiency and over 90%selectivity.Importantly,our DFT calculations and experimental results confirm that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O,and desorption of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs.The findings of this work affords a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.
文摘Non Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated w ith an aim of finding high electrocatalytic surface property for the faster electrode reactions.Electrodes w ere fabricated by electrodeposition on pure Al foil,from an electrolyte of Ni,Co,Fe salts.The optimum condition of electrodeposition w ere found out by a series of experiments,varying the chemistry of the electrolyte,pH valve,temperature,current and cell potential.Polarization study of the coated Ni-Co or Ni-CoFe alloy on pure Al w as found to exhibit high exchange current density,indicating an improved electro catalytic surface w ith faster charge-discharge reactions at anode and cathode and low overvoltage.Electrochemical impedance studies on coated and uncoated surface clearly show ed that the polarization resistance and impedance w ere decreased by Ni-Co or Ni-Co-Fe coating.X-ray diffraction(XRD),energy dispersive X-ray spectroscopy(EDX)and atomic absorption spectroscopy(AAS)studies confirmed the presence of alloying elements and constituents of the alloy.The morphology of the deposits from scanning electron microscope(SEM)images indicated that the electrode surface w as a three dimensional space w hich increased the effective surface area for the electrode reactions to take place.
基金Project (20090162120080) supported by Doctoral Fund of Ministry of Education, ChinaProject (20070410989) supported by China Postdoctoral Science FoundationProject(748310000) supported by Central South University Science Foundation for Youths, China
文摘A novel precursor of nickel-cobalt alloy powders with an appropriate Ni to Co molar ratio was prepared under selectively synthetic conditions. The composition and morphology of the precursor were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectrometry （FT-IR） and energy dispersive spectrometry （EDS）. The effects of pH value, reaction temperature, metal ion concentrations and surfactant on the morphology and the dispersion of precursor were investigated. The results show that the morphology of precursor depends on ammonia content in the precursor. A fibriform precursor is a complicated ammonia-containing nickel-cobalt oxalate. The uniform shape-controlled fibrous precursor is obtained under the following optimum conditions： ammonia as complex agent as well as pH adjustor, oxalate as coprecipitator, 50-65 °C of reaction temperature, 0.5-0.8 mol/L of total concentration of Ni2＋ and Co2＋, PVP as dispersant, and pH 8.0-8.4.
基金Project(2000-2005)supported by the New Energy and Industrial Technology Development Organization in JapanProject(2004527)supported by Scientific Research Foundation for the Returned Overseas Chinese Scholar+2 种基金Project(200594)supported by Chongqing Bureau of Personnel,ChinaProject(CSTC2005BA4016-1)supported by the National Scientific Foundation of Chongqing Municipality,ChinaProject(2003ZD31)supported by Chongqing Institute of Technology,China
文摘In order to obtain more accurate density for molten Ni-(Cr,Co,W)binary alloy,the densities of molten pure Ni and Ni-Cr,Ni-Co,Ni-W alloys were measured with a sessile drop method.It is found that the measured densities of molten pure Ni and Ni-Cr,Ni-Co,Ni-W alloys decrease with increasing temperature in the experimental temperature range.The density of alloys increases with increasing W and Co concentrations while it decreases with increasing Cr concentration in the alloy at 1 773-1 873 K.The molar volume of Ni-based alloys increases with increasing W concentration while it decreases with increasing Co concentration.The effect of Cr concentration on the molar volume of the alloy is little in the studied concentration range.The accommodation among atomic species was analyzed.The deviation of molar volume from ideal mixing shows an ideal mixing of Ni-(Cr,Co,W)binary alloys.
基金the National Natural Science Foundation of China(No.21878044,U1503194).
文摘Bimetallic catalysts(Ni-Co/AC and Ni-Fe/AC)supported on activated carbon(AC)were prepared via one-step method from coal as AC precursor with the addition of metal salts by KOH activation.The effects of the introduction of second metal(Co or Fe)into Ni/AC on the textural structure of the resultant bimetallic catalysts and their catalytic performances for methane decomposition were investigated.The results showed that active metals can be directly supported on AC by the reaction of metal species with carbon during the activation.The addition of Co or Fe to Ni/AC resulted in the decrease of specific surface area and pore volume.With increasing the loading of Co or Fe,metal alloys were formed and total surface area and pore volume declined,but the mesoporosity was increased.Bimetallic Ni-Co/AC and Ni-Fe/AC catalysts exhibited better catalytic activity and stability for methane decomposition compared than Ni/AC.The introduction of Co mainly improved initial catalytic activity;however,Ni-Fe/AC catalyst showed better behaviors in terms of reducing the deactivation rate of Ni-based catalyst than Ni-Co/AC catalyst,which is relative with the formation of Ni-Fe alloy and carbon fibers over Ni-Fe/AC.This work provides a simple and efficient approach to improve catalytic performances of Ni-based catalyst for methane decomposition.
基金supported by the National Key R&D Program of China(Nos.2021YFA1501102,2023YFA1506602)the National Natural Science Foundation of China(Nos.21932002,22276023 and 21902018)+3 种基金the National High-Level Talents Special Support Program,the Outstanding Young Scientific Talent of Dalian(2023RY011)the Fundamental Research Funds for the Central Universities(DUT20ZD205,DUT22ZD212,DUT21RC(3)095,and DUT22LAB602)Liaoning Binhai Laboratory Project(LBLF-202306)the Star Ocean Outstanding Young Talents Program.
文摘Comprehensive Summary A novel electrocatalyst,Ni-Co/β-Mo2C@C,was rationally designed to enhance the efficiency of the hydrogen evolution reaction(HER)in this work.Assembled with two-dimensional Ni-Co nanosheets onto Mo2C nanorods coated with a thin carbon shell,the catalyst demonstrates remarkable performance,including low overpotential(η10=57 mV)and reduced Tafel slope(63 mV·dec^(–1))in 0.5 mol·L^(–1)H2SO4 electrolyte.This innovative design strategy provides abundant active sites and efficient electron/ion transport pathways,effectively shortening reactant diffusion distances and enhancing electrocatalytic activity.Additionally,the carbon shell coating protects the catalyst from etching and agglomeration,ensuring its durability.This work presents a promising approach for engineering highly efficient metal carbide-based HER catalysts through tailored composition and nanostructure design.
文摘通过在镍钴双金属氢氧化物(Ni-Co LDH)的合成体系中引入胺修饰板钛矿TiO2得到了Ni-Co LDH/TiO2复合光催化材料,并对其光催化降解环丙沙星(CIP)抗生素的活性进行了研究。扫描电子显微镜(SEM)显示Ni-Co LDH将棒状的板钛矿TiO2完全包裹,增大了材料与环丙沙星分子的接触面积。当TiO2与LDH的摩尔比为1:4时,复合材料表现出最佳的催化活性且Ni-Co LDH/TiO2(1:4)在四次循环实验后仍未出现明显的活性下降,说明其具有优异的稳定性。光电化学结果证明这种结构为光催化环丙沙星降解提供了更多的活性位点,其优异的光生电子与空穴的分离和传输效率是其具有最佳催化活性的主要原因。Ni-Co LDH/brookite TiO2 composite is prepared by adding amine-modified TiO2 into the fabrication system of Ni-Co layered bimetallic hydroxide (Ni-Co LDH), and its photocatalytic degradation of ciprofloxacin (CIP) antibiotic is studied. Scanning electron microscopy (SEM) images show that Ni-Co LDH wrapped on the brookite TiO2 increases the contact area between the catalyst and ciprofloxacin molecules. It is found that when the mole ratio of TiO2 to Ni-Co LDH is 1:4, the composite exhibits the best catalytic activity, and the activity of Ni-Co LDH/TiO2(1:4) has no decrease significantly after four cycles tests, indicating that it has excellent stability. The photochemical results show that this structure provides more active sites for photocatalytic ciprofloxacin degradation, and its excellent separation and transfer efficiency of photogenerated electrons and holes are the main reason for its optimal catalytic activity.
基金This work was supported by the National Natural Science Foundation of China(Nos.51861005 and 51861004)the Innovation Project of Guangxi Graduate Education(No.YCSW2019149)Guangxi Natural Science Foundation(No.2017AD23029)。
文摘The urgent need of high-performance of energy storage devices triggers us to design newly class of materials.Generally,the materials feature with high conductivity,abundant pore s and excellent stability.Here,a sandwiched hybrid composite containing reduced graphene oxide,polypyrrole and Ni-Co layered double hydroxides(RGO/PPy/NiCo-LDH) was prepared in a facile way.The polypyrrole was incorporated in the two dimensional(2D) nanosheets,which not only serve as the spacer to increase the surface area,but also enhance the conductivity of the nanocomposite.The obtained architecture was employed as an advanced electrode in a supercapacitor.The electrode shows an ultrahigh specific capacitance(2534 F g^-1 at 1 A g^-1) and good cycling efficiency(78 % after 5000 cycles).Moreover,an asymmetric cell based RGO/PPy/NiCo-LDH composite demonstrates excellent electrochemical properties and good prospect of practical use.
