| Electrochemical sensors have many applications in the fields of environmental monitoring,information science,process control and detection,and food analysis.Therefore,the novel electrochemical sensors with low cost,simple operation,and high sensitivity have become the research hotspot.The use of metal or metal oxides for the preparation of electrochemical sensors with high catalytic activity and excellent selectivity,has attracted much attention in the field of electrochemical analysis.Au is the main representative of precious metal materials.It has strong electrical conductivity,physicochemical stability and high redox potential.It also can accelerate the transfer of electrons between electrodes.Traditionally,Au is seen as an inert element and it has no catalytic properties,but when Au reaches nanometer size,it has a catalytic reaction to many reactions.The application of Au nanomaterials to the preparation of electrochemical sensors has attracted intense attention because it has many excellent electrochemical properties.but pure Au nanostructures sometimes cannot meet the actual needs.This paper aim to use Au nanostructure as a template,combined with deposition or magnetron sputtering of other metals or metal oxides,to obtain better electrochemical sensor material.Specifically,we used a self assembly method at the air/water interface to make a two-dimensional ordered colloidal sphere template,and then a secondary template was formed by deposition of other materials.A larger specific surface area is grown on Au microarrays,which were conducted morphological appearance by SEM and XRD and TEM composition analysis.Finally,the electrochemical sensing performance was studied by an electrochemical analyzer.The specific research contentsare as follows:(1)Construction of Au micro-nano ordered array and electrochemical sensing performance studyA single-layer polystyrene colloidal sphere template was prepared by liquid surface self-assembly,and its morphology was observed by scanning electron microscopy(SEM),which was found that there was a large-area and ordered hexagonal close-packed arrangement with a colloidal sphere diameter of 500 nm.Electrodeposition method was used to synthesize large-area porous Au micron arrays on colloidal sphere templates.The morphology and composition of the samples were characterized by scanning electron microscopy(SEM)and X-ray diffraction(XRD).The results showed that the sample Au micro nanopore array had an ordered hexagonal close-packed structure over a large area,and its aperture was about 300 nm,the distance between the apertures is 500 nm,which was consistent with the diameter of the colloidal sphere.It was obviously that a template function of the colloidal sphere.Next,the electrochemical sensing performance was studied by an electrochemical working instrument.The results showed that the Au micro-nano ordered array had superior detection performance for dopamine and the detection limit was the detection range.(2)Firstly,a single-layer colloidal crystal template was prepared by a self-assembly method.A colloidal sphere template was prepared on a strictly cleaned glass substrate by a self-assembly method,and the morphology of the template was characterized by SEM electron scanning electron microscope.The template can be known through image observation anda large area of ordered hexagonal close packed arrangement with a diameter of 500 nm.Secondly,Au micro-nano ordered arrays were prepared by galvanostatic deposition method.The morphology and composition analysis were performed by SEM and XRD.Through SEM image analysis,Au nanostructures were known as large-area ordered bowled arrays,and its size and colloidal ball diameter had the same size,indicating that the colloidal ball template played a good template role.In the final experiment,the Pt nano-films were electrodeposited on the Au micro-nano ordered array structure.The morphology of the samples was compared by 1 minute,2minutes,and 3 minutes,and the cyclic voltammograms and chronoamperometric performance of the samples were analyzed by an electrochemical workstation.By contrast,it can be found that the sample had the highest catalytic activity at 2 minutes,because the thickness of the nano-film allowed electrons to be quickly transferred from the electrode to the Au substrate.Based on the electrodeposited Au ordered array on the colloidal ball template,the Au surface was loose.The conductivity was good,the Pt time on the Au electrodeposited for 2 minutes was short,and the grown Pt thickness was very thin,the specific surface area was large,and the electron conduction betweenthe Au was faster.The conductivity of the sample and the catalytic performance of the sensor has been greatly improved,and the stability has been stable.Better performance,cost-effectiveness,and simple fabrication methods,and the sensor had a detection sensitivity of 1686 A mM-1 cm-2 for H2O2,a linear range of 5 A to 6 mM,which had a minimum detection limit of 0.08 M.(3)This paper used self-assembly method to prepare for a single-layer colloidal sphere template.An Au ordered array was grown on a colloidal sphere template.The surface of the bowl-ordered array we prepared was uneven.Due to the loose and rough Au nano-array ZnO was magnetron-sputtered on the surface of this rough-surfaced structure to produce an ZnO/Aucomposite nano-ordered array structure,which resulted in a larger specific surface area than the average nanostructure,which made the intermediate layer Au effectively be improved.In The electron transfer efficiency improved the conductivity of the sample,and through data analysis,the nanoarray prepared by us reproduced the morphologies of the template itself,indicating that the template method had good controllability and reproducibility.In this experiment,in order to find the best experimental optimal performance structure,the thickness of ZnO thin film was controlled by comparing the duration of magnetron-controlled ZnO formation,and the optimal nano-array structure was determined by comparing cyclic voltammetry and chronoamperometric electrochemical performance testing.The sensitivity of the ZnO/Au composite nanoordered bowled array prepared in this paper was as high as1271A·mM-1cm-2,and the detection limit was 2,which indicated that the ZnO/Au composite nano-array was an excellent biosensor,with the simple conductionand good stablity,which has provided a new channel for the detection of H2O2. |
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