Design,Synthesis Of Functionalized Nanocarbon-based Composites And Their Electrochemical Catalytic Performance

In the recent years,the government has been devoting lots of efforts in developing high efficient,high stability and low cost catalytic materials in the field of new generation power sources.However,the traditional carbon support materials for electrocatalysts could not satisfy the recent high standard requests.There are two ways to improve the performance of carbon supported electrocatalysts.One of them is to modify the surface of carbon materials.The other way is to apply new designs and new structures to enhance the electrocatalytic performance.In this dissertation,functionalized porous carbon composites were designed and synthesized by novel soft chemistry method.The catalytic performance on alcohols electrooxidation reaction and electrocatalytic oxygen evolution reaction was also studied.1)Design of palladium nanoparticles supported on g-C3N4 modified carbon black nanocomposite and its electrocatalytic performance.In this section,g-C3N4 modified carbon black composite support materials(g-C3N4/CB)were synthesized by soft chemistry method.Then Pd nanoparticles were later supported on the g-C3N4/CB by liquid phase nucleation and Pd/g-C3N4/CB nanocomposites were obtained.In the composite,the carbon black can enhance the electron conductivity and acts as the structure support of the whole composite.The g-C3N4 layer on the carbon black can protect the carbon from the electrochemical corrosion.Besides,the g-C3N4 on carbon can also enhance the interactions between the supported metal nanoparticles and the carbon support.Moreover,the nano-sized Pd particles are the active component for electrooxidizing.From the electrochemical measurement results,the Pd/g-C3N4/CB nanocomposites were able to take full advantage of each component,and possessed extraordinary electrocatalytic properties for both formic acid oxidation and methanol oxidation than commercial Pd-C catalysts.2)Design of platinum-palladium bimetallic nanoparticles supported on g-C3N4 modified carbon black nanocomposite and its electrocatalytic performance.Inspired by the former project of Pd nanoparticles supported on the g-C3N4/CB support,in this section Pt-Pd bimetallic nanoparticles were supported on the g-C3N4/CB support.In the Pt-Pd/g-C3N4/CB composite,the g-C3N4 can contribute to uniform distribution of Pt-Pd bimetallic nanoparticles.Moreover,the unique structural characteristics and the concerted effects between Pt and Pd atoms endow the Pt-Pd/g-C3N4/CB composite with excellent catalytic activity and durability for electrooxidation of alcohols than commercial Pt/C or Pd/C catalysts.3)Design of platinum nanoparticles supported on the inner wall of hollow nitrogen doped mesoporous carbon spheres and its electrocatalytic performance.The platinum nanoparticles supported on the inner wall of hollow nitrogen doped mesoporous carbon spheres composite(Pt@C-meso)was synthesized by hard template method.The unique structure of Pt@C-meso is mainly consisted of Pt nanoparticles supported on the inner wall of carbon hollow spheres with mesopores.The structure can decrease the number of the inaccessible Pt nanoparticles buried in the carbon layers.Besides,the porous carbon wall can not only protect the Pt nanoparticles inside the carbon spheres from colliding with other Pt particles from different carbon spheres,but also increase the diffusion rate of electrolyte(including the reactant and products)through the catalyst layer,which as a result the catalytic activity and stability of Pt@C-meso could be enhanced.This project came up with a simple method to enhance the catalytic performance of a Pt/C catalyst by simply designing and modifying its structure.4)Design of sulfur doped porous carbon coated cobalt sulfide composite and its electrocatalytic performance.Cobalt sulfide is efficient in catalyzing oxygen evolution reaction(OER).However,the stability and conductivity of cobalt sulfide can not satisfy the industrial application.In this section,the cobalt sulfide was combined with sulfur doped porous carbon(Co9S8/S-C).Benefiting from the coating of sulfur doped carbon layer which can protect the cobalt sulfide particles,the stability of Co9S8/S-C composite for OER is enhanced.Moreover,the carbon layer between different cobalt sulfide particles can increase the conductivity of the composite,which resulted in high current density in OER.The Co9S8/S-C composite also had improved activity and stability than commercial RuO2 catalyst in alkaline electrolyte.