Synthesis Of One-Dimensional Palladium-based Nanocatalysts And Research For Their Application In Direct Alcohol Fuel Cells

Direct alcohol fuel cell has a wide application prospect in the field of fuel cell because of its wide range of fuel sources,ease of storage and transport,high energy conversion efficiency and being environmentally friendly.As catalyst is one of the important factors that affect its energy conversion efficiency and cost,it is extremely important and urgent for the development of direct alcohol fuel cell to solve the problem of reducing the amount of the catalysts with the improve of the catalytic properties.Focused on the design of fuel cell catalyst with high efficiency and low cost,this paper regulated and tuned the nanomaterials from the four aspects below: composition,morphology,structure and support.Several different types of one dimensional palladium-based hollow nanocatalysts have been synthesized,and their electrocatalytic properties in direct alkaline alcohol fuel cells have been investigated.The main contents and results are as follows:1.By using graphene oxide（GO）as the stabilizing and dispersing agent,Te nanowires as templates,a method for the synthesis of one-dimensional Pd-based nanotubes/ GO composites was developed.Through adding different metal salt precursors,the nanotubes/ GO composites of three different components（PdTe,PdPtTe and PdAuTe）were successfully synthesized by the method.The obtained GO-supported one-dimensional（1D）Pd-based NTs have a uniform morphology and good dispersity.The catalytical properties of PdAuTe NTs/ reduced GO（rGO）nanocomposites with different metal ratios were investigated after electrochemical reduction process.The mass activities of the obtained Pd47Au33Te20,Pd31Au49Te20 and Pd62Au17Te21 NTs/ rGO composites were5.31 mA ug^-1Pd,4.87 mA ug^-1Pd and 2.94 mA ug^-1Pd,which were 5.16,4.59 and 2.77-fold that of commercial Pd/C catalyst,respectively.This method provides a robust method and new idea for the design and synthesis of graphene-based nanocatalysts with specific morphologies.2.By using Te nanowires and Ag nanoparticles as dual templates,the novel hollow Pt nanospheres/ PdPt nanotube structure was synthesized,and the catalytic properties in ethylene glycol and glycerol electrooxidation were investigated.The obtained nanocatalyst showed the remarkable mass activity(5.21 A mg^-1metal)for the electrooxidation of ethylene glycol,which was 2.29 and 5.15-fold that of commercialPt/C and Pd/C catalyst.As for glycerol electrooxidation,it possessed the mass activity of1.60 A mg^-1metal,which was 1.46 and 3.96-fold that of commercial Pt/C and Pd/C catalyst.The as-prepared hollow Pt nanospheres/ PdPt nanotube also exhibited the greatest catalytic stability in the process of electrochemical tests.The enhanced catalytic properties should be attributed to the structure stability of one dimensional nanomaterials,the confinement of the cage effect in the zero dimensional nanostructure and the synergistic effect between Pd and Pt.The study provides constructive method and thought for template-directed synthesis of hollow nanostructures and shape-controlled nanocrystals.