Developing multifunctional electrocatalysts with high catalytic activity,longterm stability,and low cost is essential for electrocatalytic energy conversion.Herein,sea urchinlike NiMoO_(4) nanorod arrays grown on nick...Developing multifunctional electrocatalysts with high catalytic activity,longterm stability,and low cost is essential for electrocatalytic energy conversion.Herein,sea urchinlike NiMoO_(4) nanorod arrays grown on nickel foam has been developed as a bifunctional electrocatalyst for urea oxidation and hydrogen evolution.The NiMoO_(4)‐200/NF catalyst exhibits efficient activity toward hydrogen evolution reaction with a low overpotential of only 68 mV in 1.0 mol/L KOH to gain a current density of 10 mA cm^(–2).The NiMoO_(4)‐300/NF catalyst exhibits a prominent oxygen evolution reaction(OER)catalytic activity with an overpotential of 288 mV at 50 mA cm^(–2),as well as for urea oxidation reaction with an ultralow potential of 1.36 V at 10 mA cm^(–2).The observed difference in electrocatalytic activity and selectivity,derived by temperature variation,is ascribed to different lattice oxygen contents.The lattice oxygen of NiMoO_(4)‐300/NF is more than that of NiMoO_(4)‐200/NF,and the lattice oxygen is conducive to the progress of OER.A urea electrolyzer was assembled with Ni‐MoO_(4)‐200/NF and NiMoO_(4)‐300/NF as cathode and anode respectively,delivering a current density of 10 mA cm^(–2)at a cell voltage of merely 1.38 V.The NiMoO_(4)nanorod arrays has also been successfully applied for photovoltage‐driven urea electrolysis and hydrogen production,revealing its great potential for solar‐driven energy conversion.展开更多
With the increasingly urgent demand for clean water resources and the growing emission of oily wastewater,high-flux oil/water separation materials with the special wettability are progressively desired.Cellulose nanoc...With the increasingly urgent demand for clean water resources and the growing emission of oily wastewater,high-flux oil/water separation materials with the special wettability are progressively desired.Cellulose nanocrystal(CNC)from renewable biomass has been utilized to fabricate oil/water separation membranes,but it is limited to enhancing mechanical properties.Herein,a wrinkled structure with abundant–OH is constructed on polyacrylonitrile(PAN)nanofibers via the CNC hybridization process.And then,a super-hydrophilic nano-TiO_(2)shell is anchored tightly on the surface of the fiber by wrinkles and–OH.The CNC promotes significantly the in situ growth of TiO_(2),with the TiO_(2)loading ratio of up to 5.3%.The nano-TiO_(2)shell endows the obtained film with super-hydrophilicity and underwater super-oleophobicity,resulting in a visible increase of the permeation flux for the oil/water mixture from 1483 to 11,023 L m^(−2)h^(−1).Interestingly,the hierarchical structure facilitates the demulsification for oil-in-water emulsion stabilized by surfactant,allowing the obtained membrane to exhibit eminent antifouling property and high emulsion permeability of about 3,278 L m^(−2)h^(−1).This design strategy develops next-generation anchors for targeted modification on the non-reactive substrates and provides a novel pathway for fabricating oil/water separation membranes.展开更多
A label-free and sensitive electrochemical biosensing strategy for a hepatocellular carcinoma biomarker of miRNA-122 has been proposed based on hybridization induced ion-barrier effect on the electroactive sensing int...A label-free and sensitive electrochemical biosensing strategy for a hepatocellular carcinoma biomarker of miRNA-122 has been proposed based on hybridization induced ion-barrier effect on the electroactive sensing interface.First,a bifunctional electroactive electrode with the nanocomposite of Prussian blue(PB)and gold nanoparticles(AuNPs)was prepared through a two-step electrodeposition process.The PB endows the electrode excellent K^(+)-dependent voltammetric signal and the AuNPs act as the matrix for the self-assembly immobilization of the thiolated probe DNA.Upon specific hybridization of probe DNA with the target miRNA-122,the formed double duplex induced the ion-barrier effect,which blocked the diffusion of the K^(+)from the bulk solution to the electrode surface.As a result,the voltammetric signal of the PB on the electrode was surpressed,and thus the target miRNA-122 was monitored.The sensing assay showed that the miRNA-122 could be analyzed in the concentration range from 0.1 fmol/L to 1.0 nmol/L,with a detection limit of 0.021 fmol/L.The practical applicability of the biosensor was also verified by the spiking serum assay.展开更多
The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods.The product was characterized by X-ray diffraction,transmission ele...The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods.The product was characterized by X-ray diffraction,transmission electron microscopy and energy-dispersive X-ray spectroscopy.Then the obtained Au@Bi2S3 nanorods were coated onto glassy carbon electrode to act as a scaffold for fabrication of electrochemical DNA biosensor on the basis of the coordination of-NH2 modified on 5’-end of probe DNA and Au@Bi2S3.Electrochemical characterization assays demonstrate that the Au@Bi2S3 nanorods behave as an excellent electronic transport channel to promote the electron transfer kinetics and increase the effective surface area by their nanosize effect.The hybridization experiments reveal that the Au@Bi2S3 matrix-based DNA biosensor is capable of recognizing complementary DNA over a wide concentration ranging from 10 fmol/L to 1 nmol/L.The limit of detection was estimated to be 2 fmol/L(S/N=3).The biosensor also presents remarkable selectivity to distinguish fully complementa ry sequences from basemismatched and non-complementary ones,showing great promising in practical application.展开更多
In this study,the characteristics and solidification behavior of Ti-48Al-3Nb-1.5Ta powder produced by supreme-speed plasma rotating electrode process(SS-PREP®)were investigated.The microstructure,phase and charac...In this study,the characteristics and solidification behavior of Ti-48Al-3Nb-1.5Ta powder produced by supreme-speed plasma rotating electrode process(SS-PREP®)were investigated.The microstructure,phase and characteristics were analyzed by scanning electron microscopy,X-ray diffraction and other methods.The atomization mechanism is direct drop formation.The relationship between the particle size and cooling rate is vc=3.14×10^(-7)·d^(-2)+1.18×10^(-2)·d^(3/2),and the relationship between secondary dendrite arm space and the particle size isλ=0.028d+0.11,as well as the relationship between SDAS and cooling rate isλ=4.84×10^(-5)·T^(-1.43).With increase in particle size,the surface structure gradually changes from the featureless smooth structure to dendritic and cellular dendritic morphology,and the flow ability becomes better.The carbides mainly exist within 5 nm of the surface and the oxidation layer is about 20 nm thick.Ti-48Al-3Nb-1.5Ta powder was mainly composed ofα2 phase andγphase.With increase in particle size,the content ofγphase increases,and the hardness decreases accordingly.The 106–250μm particles are composed of multiple grains with the grain size of 70–80μm.The microstructure,phase composition and hardness of different TiAl powders with the same size are similar,but the elastic modulus is different.展开更多
Although many plasmonic nanosenosrs have been established for the detection of mercury(Ⅱ)(Hg^(2+)),few of them is feasible for analyzing natural samples with very complex matrices because of insufficient method selec...Although many plasmonic nanosenosrs have been established for the detection of mercury(Ⅱ)(Hg^(2+)),few of them is feasible for analyzing natural samples with very complex matrices because of insufficient method selectivity.To address this challenge,we propose an epitaxial and lattice-mismatch approach to the synthesis of a unique Au/Ag_(2)S dimeric nanostructure,which consists of an Au segment with excellent plasmonic characteristics,and a highly stable Ag_(2)S portion with minimum solubility product (K_(sp)(Ag_(2)S)=6.3×10^(-50)).The detection relies on the chemical conversion of Ag_(2)S to HgS when reacting with Hg^(2+),resulting in a red shift in the absorption band of the connecting Au NPs.The concurrent color changes of the solution from gray purple to dark green and finally to navy correlate well with Hg^(2+)concentration,thus enables UV-vis quantitation and a naked-eye readout of the Hg^(2+)concentration.This method exhibits superior selectivity towards Hg^(2+) over other interfering ions tested because Hg^(2+) is the only ion that can react with Ag_(2)S to form HgS with even smaller solubility product (K_(sp)(HgS)=4×10^(-53)).The detection limit of this method is 1.21μmol/L,calculated by the signal-to-noise of 3.The practicability of the method was verified by analyzing the Hg^(2+)in sewage water samples without sample pretreatment with satisfactory recoveries (93.1%-102.8%) and relative standard deviations (1.38%-2.89%).We believe this method holds great potential for on-the-spot detection of Hg^(2+) in environmental water samples with complex matrices.展开更多
Oxygen evolution reaction(OER)is one of the most important issues for hydrogen production from water splitting.During the OER process,electrochemical reconstruction is widely observed for the majority of electrocataly...Oxygen evolution reaction(OER)is one of the most important issues for hydrogen production from water splitting.During the OER process,electrochemical reconstruction is widely observed for the majority of electrocatalysts,which is strongly related to the formation and evolution of real active species.Herein,bimetal metal-organic framework(MOF)with an equal ratio of Co and Fe sites is screened to exhibit the superior OER property.An obvious reconstruction is observed to transform single MOF phase into the heterostructure composed of active CoOOH and FeOOH.Meanwhile,the generation of Co^(3+)species is more reliant on the blessing of electricity and electrolyte than that of Fe3+species.As a result,the optimal electrocatalyst shows the overpotential of 267 mV at 10 mA/cm^(2)and ultra-low Tafel slope of 24.7 mV/dec with a stable OER performance.展开更多
文摘Developing multifunctional electrocatalysts with high catalytic activity,longterm stability,and low cost is essential for electrocatalytic energy conversion.Herein,sea urchinlike NiMoO_(4) nanorod arrays grown on nickel foam has been developed as a bifunctional electrocatalyst for urea oxidation and hydrogen evolution.The NiMoO_(4)‐200/NF catalyst exhibits efficient activity toward hydrogen evolution reaction with a low overpotential of only 68 mV in 1.0 mol/L KOH to gain a current density of 10 mA cm^(–2).The NiMoO_(4)‐300/NF catalyst exhibits a prominent oxygen evolution reaction(OER)catalytic activity with an overpotential of 288 mV at 50 mA cm^(–2),as well as for urea oxidation reaction with an ultralow potential of 1.36 V at 10 mA cm^(–2).The observed difference in electrocatalytic activity and selectivity,derived by temperature variation,is ascribed to different lattice oxygen contents.The lattice oxygen of NiMoO_(4)‐300/NF is more than that of NiMoO_(4)‐200/NF,and the lattice oxygen is conducive to the progress of OER.A urea electrolyzer was assembled with Ni‐MoO_(4)‐200/NF and NiMoO_(4)‐300/NF as cathode and anode respectively,delivering a current density of 10 mA cm^(–2)at a cell voltage of merely 1.38 V.The NiMoO_(4)nanorod arrays has also been successfully applied for photovoltage‐driven urea electrolysis and hydrogen production,revealing its great potential for solar‐driven energy conversion.
基金the Fundamental Research Funds for the Central Universities(Grant No.2572023AW53)the Natural Science Foundation of Heilongjiang Province,China(Grant No.LH2020C039).
文摘With the increasingly urgent demand for clean water resources and the growing emission of oily wastewater,high-flux oil/water separation materials with the special wettability are progressively desired.Cellulose nanocrystal(CNC)from renewable biomass has been utilized to fabricate oil/water separation membranes,but it is limited to enhancing mechanical properties.Herein,a wrinkled structure with abundant–OH is constructed on polyacrylonitrile(PAN)nanofibers via the CNC hybridization process.And then,a super-hydrophilic nano-TiO_(2)shell is anchored tightly on the surface of the fiber by wrinkles and–OH.The CNC promotes significantly the in situ growth of TiO_(2),with the TiO_(2)loading ratio of up to 5.3%.The nano-TiO_(2)shell endows the obtained film with super-hydrophilicity and underwater super-oleophobicity,resulting in a visible increase of the permeation flux for the oil/water mixture from 1483 to 11,023 L m^(−2)h^(−1).Interestingly,the hierarchical structure facilitates the demulsification for oil-in-water emulsion stabilized by surfactant,allowing the obtained membrane to exhibit eminent antifouling property and high emulsion permeability of about 3,278 L m^(−2)h^(−1).This design strategy develops next-generation anchors for targeted modification on the non-reactive substrates and provides a novel pathway for fabricating oil/water separation membranes.
基金supported by the National Natural Science Foundation of China(Nos.21802064,81873978)Natural Science Foundation of Fujian Province(Nos.2018J01435,2019J05108)。
文摘A label-free and sensitive electrochemical biosensing strategy for a hepatocellular carcinoma biomarker of miRNA-122 has been proposed based on hybridization induced ion-barrier effect on the electroactive sensing interface.First,a bifunctional electroactive electrode with the nanocomposite of Prussian blue(PB)and gold nanoparticles(AuNPs)was prepared through a two-step electrodeposition process.The PB endows the electrode excellent K^(+)-dependent voltammetric signal and the AuNPs act as the matrix for the self-assembly immobilization of the thiolated probe DNA.Upon specific hybridization of probe DNA with the target miRNA-122,the formed double duplex induced the ion-barrier effect,which blocked the diffusion of the K^(+)from the bulk solution to the electrode surface.As a result,the voltammetric signal of the PB on the electrode was surpressed,and thus the target miRNA-122 was monitored.The sensing assay showed that the miRNA-122 could be analyzed in the concentration range from 0.1 fmol/L to 1.0 nmol/L,with a detection limit of 0.021 fmol/L.The practical applicability of the biosensor was also verified by the spiking serum assay.
基金supported by the National Natural Science Foundation of China (Nos.21802064,21275127)Natural Science Foundation of Fujian Province,China (Nos.2018J01435,2017J01419)Foundation of Key Laboratory of Sensor Analysis of Tumor Marker,Ministry of Education,Qingdao University of Science and Technology
文摘The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods.The product was characterized by X-ray diffraction,transmission electron microscopy and energy-dispersive X-ray spectroscopy.Then the obtained Au@Bi2S3 nanorods were coated onto glassy carbon electrode to act as a scaffold for fabrication of electrochemical DNA biosensor on the basis of the coordination of-NH2 modified on 5’-end of probe DNA and Au@Bi2S3.Electrochemical characterization assays demonstrate that the Au@Bi2S3 nanorods behave as an excellent electronic transport channel to promote the electron transfer kinetics and increase the effective surface area by their nanosize effect.The hybridization experiments reveal that the Au@Bi2S3 matrix-based DNA biosensor is capable of recognizing complementary DNA over a wide concentration ranging from 10 fmol/L to 1 nmol/L.The limit of detection was estimated to be 2 fmol/L(S/N=3).The biosensor also presents remarkable selectivity to distinguish fully complementa ry sequences from basemismatched and non-complementary ones,showing great promising in practical application.
基金financially supported by the Key R&D Program of Shaanxi(Program No.2022GY-388).
文摘In this study,the characteristics and solidification behavior of Ti-48Al-3Nb-1.5Ta powder produced by supreme-speed plasma rotating electrode process(SS-PREP®)were investigated.The microstructure,phase and characteristics were analyzed by scanning electron microscopy,X-ray diffraction and other methods.The atomization mechanism is direct drop formation.The relationship between the particle size and cooling rate is vc=3.14×10^(-7)·d^(-2)+1.18×10^(-2)·d^(3/2),and the relationship between secondary dendrite arm space and the particle size isλ=0.028d+0.11,as well as the relationship between SDAS and cooling rate isλ=4.84×10^(-5)·T^(-1.43).With increase in particle size,the surface structure gradually changes from the featureless smooth structure to dendritic and cellular dendritic morphology,and the flow ability becomes better.The carbides mainly exist within 5 nm of the surface and the oxidation layer is about 20 nm thick.Ti-48Al-3Nb-1.5Ta powder was mainly composed ofα2 phase andγphase.With increase in particle size,the content ofγphase increases,and the hardness decreases accordingly.The 106–250μm particles are composed of multiple grains with the grain size of 70–80μm.The microstructure,phase composition and hardness of different TiAl powders with the same size are similar,but the elastic modulus is different.
基金supported by the National Natural Science Foundation of China(No.21876206)the Key Fundamental Project of Shandong Natural Science Foundation(No.ZR2020ZD13)+1 种基金the Science and Technology Projects of Qingdao(No.21–1–4-sf-7-nsh)the Youth Innovation and Technology project of Universities in Shandong Province(No.2020KJC007)。
文摘Although many plasmonic nanosenosrs have been established for the detection of mercury(Ⅱ)(Hg^(2+)),few of them is feasible for analyzing natural samples with very complex matrices because of insufficient method selectivity.To address this challenge,we propose an epitaxial and lattice-mismatch approach to the synthesis of a unique Au/Ag_(2)S dimeric nanostructure,which consists of an Au segment with excellent plasmonic characteristics,and a highly stable Ag_(2)S portion with minimum solubility product (K_(sp)(Ag_(2)S)=6.3×10^(-50)).The detection relies on the chemical conversion of Ag_(2)S to HgS when reacting with Hg^(2+),resulting in a red shift in the absorption band of the connecting Au NPs.The concurrent color changes of the solution from gray purple to dark green and finally to navy correlate well with Hg^(2+)concentration,thus enables UV-vis quantitation and a naked-eye readout of the Hg^(2+)concentration.This method exhibits superior selectivity towards Hg^(2+) over other interfering ions tested because Hg^(2+) is the only ion that can react with Ag_(2)S to form HgS with even smaller solubility product (K_(sp)(HgS)=4×10^(-53)).The detection limit of this method is 1.21μmol/L,calculated by the signal-to-noise of 3.The practicability of the method was verified by analyzing the Hg^(2+)in sewage water samples without sample pretreatment with satisfactory recoveries (93.1%-102.8%) and relative standard deviations (1.38%-2.89%).We believe this method holds great potential for on-the-spot detection of Hg^(2+) in environmental water samples with complex matrices.
基金supported by Projects of the Natural Science Foundation of Fujian Province(No.2022J05170)the President’s Found of Minnan Normal University(Nos.KJ2021005,KJ2023002)+1 种基金the Natural Science Foundation of China(No.21275127)the High-level Incubation Program of Minnan Normal University(No.MSGJB2021003).
文摘Oxygen evolution reaction(OER)is one of the most important issues for hydrogen production from water splitting.During the OER process,electrochemical reconstruction is widely observed for the majority of electrocatalysts,which is strongly related to the formation and evolution of real active species.Herein,bimetal metal-organic framework(MOF)with an equal ratio of Co and Fe sites is screened to exhibit the superior OER property.An obvious reconstruction is observed to transform single MOF phase into the heterostructure composed of active CoOOH and FeOOH.Meanwhile,the generation of Co^(3+)species is more reliant on the blessing of electricity and electrolyte than that of Fe3+species.As a result,the optimal electrocatalyst shows the overpotential of 267 mV at 10 mA/cm^(2)and ultra-low Tafel slope of 24.7 mV/dec with a stable OER performance.
