Preparation And Methanol Electrocatalytic Performance Of Pt-based Ordered Micro-nano Arrays

With the rapid development of nanotechnology,scientists have improved the method of synthesizing nanodevices.And nanotechnology has also changed the performance of the device itself.Up to now,nanotechnology has become a very popular field in scientific research.Our research focuses on the synthesis of multi-dimensional,different morphology,superior performance of nanomaterials.At present,two-dimensional ordered array structures have shown good performance(such as in biotechnology,sensors,fuel cells,optoelectronics,magnetic and so on),so the researchers are eager to prepare a large number of novel two-dimensional ordered materials.In this thesis,a large-scale and highly ordered Pt-based porous micro/nano arrays were fabricated with the help of monolayer polystyrene sphere template.The prepared materials,which show bowl-like array structures,are deposited on the ITO\Au electrode by constant current or pulse current deposition.Then,the morphology and structure of the products were characterized,and the activity and stability to the methanol oxidation were evaluated by cyclic voltammetry and chronoamperograms methods.The main study contents are as follows:(1)A large-scale and highly ordered monolayer polystyrene colloidal spheres template was fabricated by self-assembly technique on glass substrate.Then it was observed by SEM.(2)The polystyrene colloidal crystal was used as the template.We investigated the effects of the substrate to the morphology and properties of the nanomaterials.In contrast,the colloidal spheres were transferred to the ITO or the Au electrode respectively.Then,Pt-Ni micro/nano arrays were fabricated on two substrates by the method of constant current deposition.The morphology and structure of Pt-Ni micro/nano arrays were observed by SEM and XRD.Followed by the test of catalytic performance for methanol oxidation,we found that Pt-Ni micro/nano array formed on the Au-substrate had a stronger catalytic performance and the value of peak current was twice as high as the value of that on the ITO-substrate.(3)The Pt-Co micro/nano arrays were deposited on the Au substrate by the same method.Specifically,PS template was firstly transferred to the Au substrate.Then four different electrolytes were prepared by adding CoSO4 and chloroplatinic acid.The concentration of chloroplatinic acid in the solution remained unchanged,while the concentration of cobalt sulfate was changed.Four kinds of porous Pt-Co micro/nano arrays were prepared by constant current deposition method in these different solutions.After that,the performance of catalytic for methanol was tested,and we found that corresponding to the content of 0.06 M CoSO4,the value of the peak current was a maximum with about 19 mA.We conclude that the morphology and properties of the materials would be greatly affected by the concentration of the electrolyte.(4)The Pt-Fe and Pt-Ni micro/nano arrays were deposited on the Au substrate by a pulsed electro-deposition method with the help of monolayer polystyrene sphere template.Similarly,the catalytic performance of two products for methanol fuel cells was studied.After pulsed electro-deposition,the morphologies of two products were observed by scanning electron microscopy.It was found that these arrays were different from those arrays synthesized by direct current electro-deposition.After testing the performance of catalytic for methanol by CHI660 electrochemical workstation,we found that the micro/nano arrays obtained by the pulsed current method could also be a new type of catalyst.The experiment is simple,easy to repeat,economical and environmentally friendly.