Researches On The Effect Of Noncovalent Modification Of Graphite Nanosheets To The Properties Of The Catalysts

Direct methanol fuel cell(DMFC) has advantages of low operating temperature,high energy density, easy carrying, simple structure and good safety, and has wide application prospect in portable electronic devices and automotive fields. The electrocatalyst for methanol oxidation is an important component in direct methanol fuel cell. In order to improve the catalytic activity and decrease the electrocatalyst cost, people have made lots of researches. One focus of the research in the field is using graphene as carriers of catalysts. However, ultra-thin graphene is not stable in acidic medium, and it is not easy to be anchored by catalyst particles because of its sp2 hybrid plane. How to use new catalysts carriers to overcome the above disadvantages, is a topic worthy of study. This paper adopted the method of non covalently and modified graphite microsheets with graphene structure by chemical modification, then Pt based electrocatalysts were prepared by the method of ethylene glycol liquid phase reduction. XRD, SEM or other physical characterization and CV, EIS or other electrochemical methods were used to study the electrochemical behavior of self-made catalysts, also the differences of the performance were in preliminary discussion.In this paper, organic small molecule modification graphite nanosheet supported Pt catalysts, aminopyrene and cationic modified graphite nanosheet supported Pt catalysts, and aminopyrene modified graphite nanosheets supported on Pt Pd catalysts were prepared by ethylene glycol solution phase reduction method. By physical test(TEM?XRD?XPS?Raman spectroscopy)and electrochemical test(CV?EIS?CA) we investigated the effect of structure, morphology, surface chemical state to electrocatalytic performance in different systems of catalysts supported on graphite nanosheet modified with different quality and kinds of small organic molecules, at the same time investigated the effect of the morphology and catalytic properties of the catalysts with cation or different PtPd ratio, also the reason for the difference of their performance were also discussed. The results showed that the small organic molecules with different contents, catalytic activity and stability of catalysts were significantly different. In acidic system when the organic small molecule was aminopyrene, catalysts had the best catalytic properties to the oxidation of methanol; In acidic system when the organic small molecule was PTCDI, catalystshad the best catalytic properties to the oxidation of ethanol. With different cations adding on catalysts, the catalysts had different catalytic properties, and when the cation was Al3+, the catalytic activity and stability of catalysts were best. However,according to the synergistic effect of Al3+ and the amino pyrene, the catalyst particles formed micro three-dimensional structure, and changed the content of Pt0, Pt with high state, furthermore improve the performance of electrocatalysts. When the content of amino pyrenequality or the ratio of Pd and Pt was different in binary alloy catalysts, electrocatalytic properties of catalyst were different.