The Synthesis Of Novel Noble Metallic Nanomaterials Supported On Carbon And Their Performance Study Toward Methanol Electro-oxidation

Direct alcohol fuel cell as a kind of no pollution,wide source of fuel,high energy conversion rate,easy storage and transportation of green energy technology,has become the research hotspot in the field of new energy.In order to improve the performance of the fuel cell and promote the commercialization of alcohol fuel cell,how to reduce the cost and optimize the performance of the electrode catalyst is the important and difficult item.At present,precious metal Pt is still considered to be the most effective catalyst for methanol.While its expensive price,low storage and easy poisoning by intermediate CO in the process of application,greatly restricted the commercialization of fuel cells.Therefore,improving the utilization of precious metals and catalytic efficiency has become one of the current research focuses in fuel cell.The present works will focus on the effect of composition,structure and synthesis methods of carbon carrier materials loading Pt or Pd based catalyst for the methanol electrocatalytic performance.The main contents are as following:Graphite nanoplates were prepared by the modified Hummers method and mechanical stripping method for the first time.Pd nanoparticles supported on graphite nanoplates were successfully synthesized by a simple one-step reduction methold,in which sodium borohydride is acted as reducing agent.The experimental results show that the graphite nanoplates producing by this new preparation method is not only simple and fast,but also high yield.Pd nanoparticles with the average size of 11.5 nm can be well dispersed on graphite nanoplates.These composite materials exhibited excellent catalytic activity and poison resistance toward methanol electrooxidation in alkaline conditions,which is much better than Pd load on the reduced graphene oxide prepared by traditional modified Hummer's method and commercial carbon black Vulcan XC-72,respectively.To further improve the catalytic performance of the catalyst.We set our sights on the bimetallic catalyst.Considering the Au has excellent resistance to CO poison,we synthsize core-shell Au-Pt bimetallic nanoparticles.During the process of preparation,the growth of Pt nanoparticles on the Au core was effectively controlled by changing the reduction time of the reducing agent(ascorbic acid).In the further electrochemical evaluation,the core-shell Au-Pt nanoparticles supported on Vulcan XC-72 show better electrocatalytic activity and poison tolerance toward the oxidation of methanol than those of commercial Pt supported on carbon black.The environmentally friendly synthetic method and the special structure of Au-Pt nanomaterials could be found great potential in the application of new energy materials.Except for the reseach of core-shell structure of bimetallic nanomaterials,we also discuss the structure and properties of alloy nanocatalysts.Bimetallic PtPd nanocrystals with uniform size(7 nm)were successfully fabricated by a clean and facile method in aqueous solution at ambient temperature,in which ascorbic acid acted as soft and green reductant.This PtPd alloy nanoparticles can be evenly dispersed on carbon black through mechanical stirring to form PtPd NPs/V composite nanomaterials.The as-synthesised PtPd NPs/V shows great catalytic activity and super poisoning tolerance for methanol oxidation in alkaline media than those of monometallic Pt NPs/V and Pd NPs/V.