石颈镇
黄尾鱼摘要
摘要切眼
中空碳球（HCS）作为一种新型甲醇燃料电池的电催化剂载体，由于其结构可控、密度低、比表面积高和电催化性能良好等性质，受到了国内外科学工作者的广泛关注。模板法作为一种简单的制备可控形状物质的方法，开辟了制备中空碳球的一个全新领域。本论文分别以二氧化硅和聚苯乙烯作为核模板合成中空碳球，同时将Pt纳米粒子催化剂包裹在中空碳球的内部，使中空碳球功能化，合成Pt纳米粒子催化剂核/中空碳壳（Pt@C）微球，并研究了将其用于甲醇燃料电池电极的催化性能。
主要研究工作如下：
1．以二氧化硅为核模板，酚醛树脂为碳源，分别采用聚乙烯吡咯烷酮（PVP）、十六烷基三甲基溴化铵（CTAB）和3-氨丙基三乙氧基硅烷（APTS）对二氧化硅表面进行功能化修饰，合成中空碳球，并通过控制酸催化缩聚反应的作用点，得到了不同形貌的碳材料。用SEM、FT-IR和TGA对所制材料进行了表征。研究结果证明，修饰剂的选择对中空碳球的形貌和稳定性具有很大的影响，APTS作为二氧化硅表面修饰剂，通过氢键与酚醛树脂结合，因此所形成的中空碳球的球形结构和稳定性最好。此外，不同的酸催化活性点对碳材料表面形态也有很大影响。通过改变酸催化缩聚反应的作用点，可以得到单一分散的中空碳球和有序排列的多孔碳材料。假如爱有天意纯音乐
2．以磺化聚苯乙烯球为模板，苯胺为碳源，制备中空碳球。采用SEM、TEM、XRD、FT-IR、TGA和CV对所制的样品进行了表征。研究结果表明，制备的中空碳球壁厚为35nm 且粒径均匀，中空碳球的形貌和壳层厚度受聚苯乙烯模板磺化度的影响。对聚苯乙烯球表面进行磺酸化8h是制备中空碳球最合适的模板。CV研究结果表明，将所制备的中空碳球（HCS）用作催化剂载体，合成Pt/HCS催化剂在甲醇电化学氧化中表现出较Pt/C催化剂更高的催化性能，其甲醇电化学氧化峰电流密度比Pt/C催化剂高了1.86倍。
元旦晚会宣传语幼儿集体游戏3．采用模板法制备了铂纳米核/中空碳壳（Pt@C）微球，作为一种新颖的催化剂，将其应用于甲醇燃料电池催化剂，并用XRD、SEM-EDS、TEM、TGA、N2吸附和CV等手段对材料的催化剂粒径、负载情况及催化性能进行了表征。研究结果表明，中空碳球表面存在介孔结构，铂纳米粒子催化剂均匀的分散在中空碳球内部，并在甲醇燃料电池的甲醇氧化中显现出良好的催化性能。
关键词：模板法；表面功能化；核/壳；中空碳球；甲醇燃料电池
汕头大学硕士学位论文
Abstract
Hollow carbon spheres as a novel electrocatalyst support for direct methanol fuel cell has been attra
cted considerable attention owing to their tailored structures,low density,high surface area,thermal insulation and electronic properties.Template approach has opened a new filed to prepare hollow carbon spheres due to its many advantages,including controllable of structure size and simple to synthesize.In this paper,two common highly disperd templates,the silica and polystyrene particles,are employed to synthesize hollow carbon spheres.To fully exploit the versatile hollow carbon spheres，the fabrication of hollow carbon spheres functionalized with multiple Pt nanoparticles in core and carbon as shell has also been obtained.Further more,its catalytic performance are studied in direct methanol fuel cell electrode.
The main rearch work is as follows:
1.Silica particles as core template,Phenolic Resin(PF)as carbon source,three different surface modified agents, including PVP, CTAB and APTS are employed to functionalize modification of silica and prepare hollow carbon spheres.The synthesis of nanostructured carbon materials with different morphologies has also been demonstrated by simply altering acid-catalyst sites.The as-prepared products are characterized by SEM,FT-IR and TG.A. Experimental results show that the morphology and stability of the hollow carbon spheres are affected by different surface modified agents.APTS as a silane coupling agent could react with PF through hydrogen bonding.Therefore,the hollow structure
s of carbon spheres are much better and stable.By simply regulating the initiation sites of the acid-catalyzed condensation reaction from the same polymer precursor on silica templates,porous carbon materials with highly ordered and3D interconnected spherical voids and hollow carbon spheres with highly monodisperd are prepared,respectively.武汉万国公园
2.Polystyrene(PS)spheres as core template and aniline monomer as carbon source are ud to prepare hollow carbon spheres(HCS).The particles prepared are characterized by SEM,TEM, XRD,FT-IR,TGA,N2and CV.Experimental results indicate that the as-prepared hollow carbon spheres are uniform in diameter with the shell thickness of35nm.The morphology,diameter and thickness of the hollow carbon spheres can be controlled by varying the sulfonation rate of PS core template.Sulfonation modification of PS particles for8h is the most appropriate template to prepare hollow carbon spheres structure.It is also proved by CV result that the Pt/HCS shows peak current density for methanol oxidation is1.86times higher than that on Pt/C electrocatalyst
Abstract
at the same Pt loadings.
国庆节活动总结3.Hollow carbon spheres functionalized with multiple Pt nanoparticles in core and carbon as shell ar
e fabricated via template method.Then,catalytic performance is studied in direct methanol fuel cell electrode.The catalyst particle size,loading and catalytic properties are also investigated by XRD,SEM-EDS,TEM,TGA,N2and CV.The results show that the prence of mesopores on the surface of Pt@C materials.Pt nanoparticles evenly disper in the interior of hollow carbon sphere,and reveal good electrocatalytic activity towards the oxidation of methanol.
Keywords:Template approach;Surface functionalization;Core/shell;Hollow carbon spheres;
Direct methanol fuel cells(DMFC)
