Preparation Of Platinum-based Composite Modified Electrode And Application For Methanol Fuel Cell

The fuel cell as a clean and efficient power generation technology,is expected to solve the current energy probloms for human.Direct methanol fuel cell has been widely studied in the portable power and automotive power due to its high energy efficiency and easy storage.However,the activity and stability of the catalysts have limited their large-scale commercialization.In this paper,Pt was used for the base material which composited several kinds of materials as catalysts,and Pt-based composited modified elcetrods were prepared.The electrocatalytic activity and electrochemical stability of methanol were studied.Firstly,the catalysts of Pt₃Ni/CS-RGO?PtNi/CS-RGO?PtNi₃/CS-RGO and Pt₃Ni/RGO were prepared by impregnation reduction method using graphene oxide modified by chitosan as supporter.The catalysts were characterized by transmission electron microscopy?TEM?,X-ray diffraction?XRD?and X-ray photoelectron spectroscopy?XPS?.The electrocatalytic activity and stability of the catalysts for methanol oxidation were investigated by cyclic voltammetry?CV?,electrochemical impedance spectroscopy?EIS?and Chronoamperometry?CA?.TEM results showed that the addition of chitosan was conducive to loading more platinum-nickel metal particles and increasing the dispersion of metal particles.CV and CA results showed that Pt₃Ni/CS-RGO had the higher activity and stability for methanol electrocatalytic oxidation and the peak current density of Pt₃Ni/CS-RGO reached 189.89mA/mg in the solution of 1.0 mol/L KOH+1.0 mol/LCH₃OH and the value of I_n/I₀ on Pt₃Ni/CS-RGO was 54.48%after 1000 cycles which was higher than the other three catalysts.The results indicated that Pt₃Ni/CS-RGO exhibited higher electrocatalytic activity and better stability.Secondly,the catalysts of PtNi₃/CeO₂/RGO?PtNi/CeO₂/RGO?Pt₃Ni/CeO₂/RGO and PtNi₃/RGO were prepared by impregnation reduction method using graphene oxide modified by cerium oxide as supporter.The catalysts were characterized by TEM,XRD and XPS.The electrocatalytic activity and stability of the catalysts for methanol oxidation were investigated by CV,EIS and CA.TEM results showed that cerium oxide like stick was doped in graphene oxide.CV and CA results showed that PtNi₃/CeO₂/RGO had the higher activity and stability for methanol electrocatalytic oxidation and the peak current density of PtNi3/CeO2/RGO reached 406.62 mA/mg in the solution of 1.0 mol/L KOH+1.0 mol/LCH3OH and the value of I_n/I₀ on PtNi₃/CeO₂/RGO was 64.16%after 1000 cycles which was higher than the other three catalysts.The results indicated that PtNi3/CeO2/RGO exhibited higher electrocatalytic activity and better stability.Pt₃Ni/CS-RGO and PtNi₃/CeO₂/RGO were used to compared for methanol electrocatalytic activity and stability by using the CV method and CA method.The value of I_f/I_b on PtNi₃/CeO₂/RGO was 1.28 times as largr as that on Pt₃Ni/CS-RGO.The value of In/I₀on PtNi3/CeO2/RGO was still 64.16%after 1000 cycles,which was higher than 54.48%of the Pt3Ni/CS-RGO.The results indicated that PtNi3/CeO2/RGO exhibited higher electrocatalytic activity and better long-term cycle stability.