The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to ...The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy (SEM) and energy dispersed X-ray spectroscopy (EDX) were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction (XRD) was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V (vs SCE). The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag+ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2+ and Ag+ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.展开更多
Although surface-enhanced Raman spectroscopy(SERS)substrates have achieved high sensitivity,it is still difficult to apply these SERS protocols to the on-site detection of real samples due to the SERS substrate being ...Although surface-enhanced Raman spectroscopy(SERS)substrates have achieved high sensitivity,it is still difficult to apply these SERS protocols to the on-site detection of real samples due to the SERS substrate being fabrication-complexed,unstable,reproducible,or unable to be applied in batch production.Here,a large-scale ordered two-dimensional array of Au nano-hemispheres was developed through electron beam vaporization of Au onto the easy-available commercialized anodic aluminum oxide(AAO)template with two-layer nanostructures of different diameters.The uniform Au nano-hemisphere is reliable for SERS detection of malachite green(MG)due to the relative standard deviation(RSD)of the SERS intensities at different locations less than 10%.With the optimized excitation wavelength,solvent effect and pH environment,the linear range of MG detection spans from 10^(-10) to 10^(-6) mol/L with a limit of detection(LOD)of 4×10^(-10) mol/L.The enhancement factor can reach 1.2×10^(6).After extraction with acetonitrile and dichloromethane,MG in the spiked tilapia was detected with satisfactory recovery.The results indicate that the Au nano-hemisphere array can be expected to greatly facilitate SERS practical applications in detecting harmful food additives and chemicals due to the advantages of chemical inertness,physical robustness,simple fabrication,controllability,large-area uniformity,and large-batch production.展开更多
An electroless deposition(ELD) method is introduced to fabricate a metal nanoplug for its advantages of simplicity,low cost and auto-selectivity.It was demonstrated that nanoplugs of less than 50 nm in diameter can ...An electroless deposition(ELD) method is introduced to fabricate a metal nanoplug for its advantages of simplicity,low cost and auto-selectivity.It was demonstrated that nanoplugs of less than 50 nm in diameter can be fabricated by ELD nickel on various substrates,such as silicon,tungsten and titanium nitride.The main composition of the ELD nanoplug was characterized as nickel by an energy dispersive X-ray microanalyzer.A functional vertical phase-change random access memory(PCRAM) device with a heater diameter of around 9μm was fabricated by using the ELD method.TheⅠ-Ⅴcharacteristics demonstrated that the threshold current is only 90.8μA.This showed that the ELD process can satisfy the demands of PCRAM device application,as well as device performance improvement.The ELD process provides a promising method for the simple and low-cost fabrication of metal nanoplugs.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.20373015the Hunan Education Office under Grant No.04C033.
文摘The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy (SEM) and energy dispersed X-ray spectroscopy (EDX) were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction (XRD) was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V (vs SCE). The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag+ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2+ and Ag+ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.
基金the National Natural Science Foundation of China(32272417)the National Key Research and Development Program of China(2018YFC1602802)+1 种基金the Natural Science Foundation of Fujian Province,China(2020J01681)the Open Project of PCOSS,Xiamen University,China(201926).
文摘Although surface-enhanced Raman spectroscopy(SERS)substrates have achieved high sensitivity,it is still difficult to apply these SERS protocols to the on-site detection of real samples due to the SERS substrate being fabrication-complexed,unstable,reproducible,or unable to be applied in batch production.Here,a large-scale ordered two-dimensional array of Au nano-hemispheres was developed through electron beam vaporization of Au onto the easy-available commercialized anodic aluminum oxide(AAO)template with two-layer nanostructures of different diameters.The uniform Au nano-hemisphere is reliable for SERS detection of malachite green(MG)due to the relative standard deviation(RSD)of the SERS intensities at different locations less than 10%.With the optimized excitation wavelength,solvent effect and pH environment,the linear range of MG detection spans from 10^(-10) to 10^(-6) mol/L with a limit of detection(LOD)of 4×10^(-10) mol/L.The enhancement factor can reach 1.2×10^(6).After extraction with acetonitrile and dichloromethane,MG in the spiked tilapia was detected with satisfactory recovery.The results indicate that the Au nano-hemisphere array can be expected to greatly facilitate SERS practical applications in detecting harmful food additives and chemicals due to the advantages of chemical inertness,physical robustness,simple fabrication,controllability,large-area uniformity,and large-batch production.
基金Project supported by the National High-Tech Research and Development Program of China(No2008AA031402)the National Natural Science Foundation of China(Nos60606024,61076077)
文摘An electroless deposition(ELD) method is introduced to fabricate a metal nanoplug for its advantages of simplicity,low cost and auto-selectivity.It was demonstrated that nanoplugs of less than 50 nm in diameter can be fabricated by ELD nickel on various substrates,such as silicon,tungsten and titanium nitride.The main composition of the ELD nanoplug was characterized as nickel by an energy dispersive X-ray microanalyzer.A functional vertical phase-change random access memory(PCRAM) device with a heater diameter of around 9μm was fabricated by using the ELD method.TheⅠ-Ⅴcharacteristics demonstrated that the threshold current is only 90.8μA.This showed that the ELD process can satisfy the demands of PCRAM device application,as well as device performance improvement.The ELD process provides a promising method for the simple and low-cost fabrication of metal nanoplugs.