Preparation Of Hollow Carbon Spheres And Their Appliation In Direct Methanol Fuel Cells

Hollow carbon spheres as a novel electrocatalyst support for direct methanol fuel cell hasbeen attracted considerable attention owing to their tailored structures, low density, high surfacearea, thermal insulation and electronic properties. Template approach has opened a new filed toprepare hollow carbon spheres due to its many advantages, including controllable of structuresize and simple to synthesize. In this paper, two common highly dispersed templates, the silicaand polystyrene particles, are employed to synthesize hollow carbon spheres. To fully exploit theversatile hollow carbon spheres,the fabrication of hollow carbon spheres functionalized withmultiple Pt nanoparticles in core and carbon as shell has also been obtained. Further more, itscatalytic performance are studied in direct methanol fuel cell electrode.The main research work is as follows:1. Silica particles as core template, Phenolic Resin (PF) as carbon source, three differentsurface modified agents, including PVP, CTAB and APTS are employed to functionalizemodification of silica and prepare hollow carbon spheres. The synthesis of nanostructuredcarbon materials with different morphologies has also been demonstrated by simply alteringacid-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 areaffected by different surface modified agents. APTS as a silane coupling agent could react withPF through hydrogen bonding. Therefore, the hollow structures of carbon spheres are muchbetter and stable. By simply regulating the initiation sites of the acid-catalyzed condensationreaction from the same polymer precursor on silica templates, porous carbon materials withhighly ordered and 3D interconnected spherical voids and hollow carbon spheres with highlymonodispersed are prepared, respectively.2. Polystyrene (PS) spheres as core template and aniline monomer as carbon source are usedto prepare hollow carbon spheres (HCS). The particles prepared are characterized by SEM, TEM,XRD, FT-IR, TGA, N2 and CV. Experimental results indicate that the as-prepared hollow carbonspheres are uniform in diameter with the shell thickness of 35nm. The morphology, diameter andthickness of the hollow carbon spheres can be controlled by varying the sulfonation rate of PScore template. Sulfonation modification of PS particles for 8 h is the most appropriate templateto prepare hollow carbon spheres structure. It is also proved by CV result that the Pt/HCS showspeak current density for methanol oxidation is 1.86 times higher than that on Pt/C electrocatalyst atthesamePtloadings.3. Hollow carbon spheres functionalized with multiple Pt nanoparticles in core and carbonas shell are fabricated via template method. Then, catalytic performance is studied in directmethanol fuel cell electrode. The catalyst particle size, loading and catalytic properties are alsoinvestigated byXRD, SEM-EDS, TEM, TGA, N₂and CV. The results show that the presence ofmesopores on the surface of Pt@C materials. Pt nanoparticles evenly disperse in the interior ofhollow carbon sphere, and reveal good electrocatalytic activity towards the oxidation ofmethanol.