Research On Catalyst Of Directmethanol Fuel Cell: Pt/aniline-graphene

Direct methanol fuel cell(DMFC) has become one of the best solutions to the energy supply of portable electronic devices due to the advantages of high energy density and efficiency, simple structure, lack of pollution, etc. Nevertheless, there are still several challenges impeding the commercialization of DMFCs. As the core of DMFCs, catalysts suffer from the small specific surface area during the electrochemical process, which leads to the low activity of catalysts and the high cost of DMFCs.With its unique two-dimensional structure, graphene has excellent physical and chemical properties and stabilities, making it ideal for the support of catalyst. However, the aggregation between the separated graphene sheets through the force of van der Waals can largely reduce the uniformity of the dispersal of Pt nanoparticles and thus limits the activity of catalyst. In this paper, aniline was utilized to modify graphene nanosheets, which were served as the support of Pt nanoparticles. Electrochemical measurements and several physical characterizations were conducted to study the performance of the catalysts.The catalyst, denoted as Pt/NCL-RGO, was obtained by dispersing Pt nanoparticles on the aniline-modifying graphene sheets. Aniline formed a nitrogen-doped carbon layer between graphene sheets after treatment, which hindered the agglomeration between them. Results of electrochemical tests indicate that Pt/NCL-RGO has a larger electrochemical surface area. The catalytic activity and stability of the catalyst towards methanol oxidation are obviously improved.Further improvement has been made on the basis of previous work. Ethylene diamine tetraacetic acid(EDTA) was introduced to the preparation of catalyst. EDTA, combined with aniline, formed a porous carbon layer and increased the exposed area of Pt particles. The catalyst supported by porous carbon layer functioning graphene, Pt/P-RGO-F, was acquired via freeze-drying. Transmission electron microscopy test shows that Pt nanoparticles were uniformly dispersed on graphene nanosheets, which barely aggregated. The ESA of Pt/P-RGO-F significantly increases to the value of 68.91m2/g. Compared to the catalyst obtained by directly dispersing Pt particles on graphene sheets, the catalytic activity toward methanol electro-oxidation of Pt/P-RGO-F is increased by 74.7%. Besides, it also exhibits much better stability.