Preparation And Electrochemical Performance Of Pt-based High-index Crystal Face Nanocatalyst

Nowadays,the world is faced with a series of serious problems such as energy depletion,environmental pollution and so on.Therefore,how to solve these problems becomes particularly important.Direct ethanol fuel cells(DEFC)have attracted much attention because of their advantages such as easy availability of fuel,green efficiency and so on.However,the promotion of fuel cells is greatly hindered due to the influence of catalysts in the development process.At present,the active ingredients of catalysts in fuel cells mainly rely on precious metals such as Pt.However,such precious metals catalysts have problems such as high price,low catalytic performance and poor stability.Therefore,it is a major problem to find new and efficient catalysts.According to the research findings,the catalysts with a large number of steps and twisted atoms on the surface of the h igh index crystal plane show very high catalytic activity.However,it is difficult to synthesize catalyst with high index plane,so it is very important to find a simple and convenient method to synthesize catalyst with high index plane.The effect of PVP and glycine on the synthesis of Pt high index planar catalyst was studied by using XRD,TEM,SEM and so on.The electrocatalytic performance of the prepared catalyst was tested by electrochemical workstation.It was found that the performance of the prepared catalyst was better than that of the commercial catalyst.When the mass ratio of PVP to Pt was 50:1 and the molar ratio of Glycine to Pt was 24:1,the Pt nanocrystals with{310},{520}and{830}crystal planes with high exponent were prepared.Electrochemical test results showed that the peak current density for ethanol oxidation was 2.194 m~2/g,and the steady-state current density was 0.241 mA/cm~2,which was 5.7 times higher than that of commercial catalyst.In order to further improve the catalytic activity and stability of the catalysts,a series of Pt-Ni high index facet nanocrystals were prepared by hydrothermal method.By adjusting the molar ratio of Pt to Ni,a series of Pt-Ni high index facet nanocrystals were prepared and characterized by XRD,SEM,TEM,XPS and so on.The electrocatalytic performance of the prepared catalyst was tested by electrochemical workstation.The results showed that the catalytic activity and stability of the prepared catalyst were better than those of commercial catalysts.When Pt:Ni=1:1,the prepared catalyst showed the best catalytic performance.Its electrochemical active surface area is 8.546 m~2/g,and the peak current density for ethanol oxidation is 4.544 mA/cm~2.The results showed that the doping of Ni could not only reduce the amount of Pt but also improve the catalytic efficiency of the catalyst for ethanol.In order to further improve the activity of the catalyst,the prepared PtNi high index crystal face nano-catalyst was acid etched.The effects of different etching time on microstructure and electrocatalytic performance were investigated.The results showed that when the etching time was 48 hours,the catalyst exhibited the best catalytic performance,with the electrochemical active surface area of 11.572 m~2/g and the oxidation peak current density of6.397 mA/cm~2 for ethanol,which indicated that the catalytic performance of the catalyst could be enhanced by the etching treatment.