Designed Synthesis Of Special Nano-assembly Materials Support Noble Matel Electrocatalysts And Its Performance Investigation

As one of the low-temperature fuel cells,direct alcohols fuel cells(DAFCs)are environmentally friendly.DAFCs possess some features such as high energy conversion efficiency,clean environmental fuel and simple battery structure,so that they have great potential for future mainstream energy equipment.However,the performance and efficiency of fuel cell system is essentially governed by the electro-catalyst which includes metal nanoparticles and support materials.Among the electro-catalyst,the support materials can directly affect the particles size,dispersion,catalytic efficiency and stability of metal nanoparticles catalyst.Therefore,more and more researchers devote themselves to explore new support materials,to improve the utilization rate of noble metal nanoparticles and stability as far as possible through morphology effect,supports effect and synergy.In this paper,we seriously studied the special structures and morphology of support materials,and designed as well as synthesized a series of new composite catalysts.To further evaluate the electro-catalytic performance of as-prepared catalysts,the effect of special nano-assembly support materials on electrocatalytic performance of noble metal nanoparticles was discussed.These studies might provide a new idea and a basic theoretical reference for designing suitable catalyst support materials.The main contents of this paper were summarized as follows:Firstly,the novel Ag@C nanocables were successfully synthesized and employed as the Pt nanocrystal catalyst support material for the first time.The Pt nanoparticles were in-site reduced supported on this Ag@C nanocable materials showed uniform dispersion.We also investigated the influence of Ag core on the morphology,particle size and electro-catalytic properties of Pt nanoparticles.According to the results of morphology and structure,Ag@C supports were 1D nanocables with Ag nanowires as the cores and carbon as sheath.The platinum nanocrystals were highly dispersed in supports surface with a mean size of 4.4 nm.Electrochemical measurements demonstrated that this Pt/Ag@C catalyst could have both superior electro-catalytic activity and stability for alcohols oxidation.Theoretical calculation was also carried out for fundamental understanding of the Pt/Ag@C catalyst.It strongly demonstrated that Ag@C supports were attributed to Pt nanoparticles anchoring,catalytic performance and COads poison tolerance.Secondly,a two-step strategy was employed to preparation Ag@C nanocables supported Pd nanocrystals catalysts(Pd/Ag@C).In the synthesised of catalysts,Ag@C nanocables were employed as the support materials and ammonia was employed as addition agent.The results showed that the as-prepared Pd nanoparticles were well-dispersed on the surface of Ag@C nanocables and exhibited obvious increase in electro-catalytic activity and stability towards alcohols oxidation.It demonstrated that the presence of Ag nanowires is a key factor in controlling and regulating the shape and size of the Pd nanoparticles,and might contribute to the good electro-catalytic activity.Electrochemical analysis showed that the Ag@C nanocables may be a better potential candidate to be used as the supports of catalyst in DAFCs.Thirdly,the ternary heterogeneous structure Pt-Pd Co catalyst was supported on Ag@C nanocables by using the glutamic acid was used as modifier for supports through simply alloy and partial displacement reaction.According to transmission electron microscopy(TEM)and energy dispersive spectrum analysis(EDS)measurements,the as-prepared Pt-Pd Co catalyst had special cluster structures,and Pt nanoparticles were deposited on the surface of the PdCo alloy.Cyclic voltammetry and chronoamperometry measurements demonstrated that the as-prepared Pt-Pd Co/Ag@C catalyst exhibited superior electro-catalytic activity and stability for alcohol oxidation compared with commercial 20% Pt/C catalysts.Fourthly,we synthesized flower-like copper and copper oxide composite materials supported Pt catalyst(Pt/F-Cu/Cu O)for alcohols electro-oxidation.Glucose and copper chloride was used as carbon and copper source,respectively.The flower-like Cu/CuO support materials(F-Cu/CuO)were successfully synthesized through nano-assembly by the template-free pyrolysis and corrosion method.The resulting of F-Cu/CuO nanostructures and none flower-like Cu/CuO(N-Cu/CuO)were characterized by X-ray diffraction(XRD),field emission scanning electron microscope(FESEM)and transmission electron microscope(TEM).The electrocatalytic properties of the Pt/F-Cu/CuO catalysts for alcohols oxidation had been systematically investigated by typical electrochemical methods.The Pt/F-Cu/CuO catalyst showed higher electrocatalytic activity,better long-term stability and stonger COads resistance.In conclusion,based on the synthesis and application of new type supports,we synthesized nano-assembly support materials with special morphology and used them to support noble metal catalyst,based on the synthesis and application of new type supports.The performance of the synthesized catalysts was remarkable.At the same time,we studied the effects of morphology,supports and synergy on catalystsactivity through scientific characterization methods.