Preparation And Methanol Electrocatalytic Performance Of Pt-based Nanostructures On Ni Foam

The direct methanol fuel cell?DMFC?has attracted much attention as a green and clean energy source in the fields of hybrid electrical vehicles and portable electronics.To achieve a wider range of use in commercialization,highly active electrocatalysts for oxidation of methanol are desired to be obtained.As for methanol oxidation reaction,Pt catalyst is currently the most investigated due to its high electrocatalystic activity.But,apart from its high cost and scare,Pt is prone to poisoning by CO species,intermediates formed during the dehydrogenation of methanol,which limiting its practical application seriously.To resolve these problems,Pt-based alloys are often used to increase the catalyst performance of MOR,which can also decrease the noble metal wastage.As a porous metal,Ni foam has three-dimensional full through mesh structure and excellent performance.Its skeleton is hollow and connected to each other in a metal state,which make Ni foam has the advantages of good stability,high porosity,thermal shock resistance,small bulk density and large specific surface area and make it has a great potential for application as a catalyst base.In this thesis,Pt-based nanostructures were fabricated on Ni foam by electrochemical deposition method with the control of deposition parameters.The morphology and structure of the Pt-based nanostructures were characterized by scanning electron microscopy and energy dispersive spectrometer.Then,the activity and stability of the Pt-based nanostructures on Ni foam electrode to the methanol oxidation were evaluated by cyclic voltammetry and chronoamperograms methods.The results indicated that the Pt-based nanostructures on Ni foam were a promising new class of catalyst for methanol oxidation and for direct methanol fuel cell applications.The main contents of this paper are as follows:1.Constant voltage deposition is carried out at different voltages?0.6V,0.8V,1.3V?in H₂PtCl₆ solution on Ni foam and we found that different deposition voltages lead to the different coverage of Pt on the surface of Ni foam,which leads the different catalytic performance of the prepared samples.2.Constant voltage deposition is carried out at different voltages?0.6V,0.8V,1.3V?in H₂PtCl₆/CoCl₂/CoSO₄ solution based on Ni foam and we found that Pt/Co alloy can further improve the catalyst against CO poisoning and resistance to CO poisoning is related to the content of Co.3.On the basis of the above experiments,we found a method to improve the Co content of Co-Pt alloy catalyst.Constant voltage deposition is carried out at different voltages?1V,1.5V,2V?in NiCl₂/NiSO₄/CoCl₂ solution based on Ni foam for a long time and then soak them in H₂PtCl₆ solution for replacement reaction and finally synthesized Pt-Ni-Co nano catalyst on Ni foam.The experiment results show that Pt-Ni-Co nano catalyst on Ni foam performs a better catalyst properties.