Synthesis And Study On The Pt/CeO₂/r-NGO Composite Catalysts For Fuel Cells

Recent years, fuel cells has increasingly become the focus of the researchers,because of its advantages of highly efficient, green, safe and so on. While the anodecatalyst not only affect the overall performance of the fuel cell, but also has closelycontaction with the commercial cost of the fuel cells. So the anode catalyst plays apivotal position in the fuel cell system. At present,the main research direction focus onaspects of catalytic activity, CO tolerance, stability, and reduce the amount of preciousmetals used. Considering the above, in this paper we synthesized a catalyst withthree-dimensional structure, by self-assembled of graphene materials and CeO₂microspheres and characterized the catalytic performance and catalytic mechanismsystematically.Reduced state nanoscale graphene layer and CeO₂nanoparticles are used as thepreliminary materials, through the ethylene glycol step reduction methed synthesizedPt/CeO₂/r-NGO （reduced nanoscale graphite oxide） catalysts with a specific structure,high-resolution transmission electron microscopy and linear sweep of the catalystreveals Pt/CeO₂/r-NGO catalyst take the CeO₂microspheres as core, and its diameter isabout77.3nm, r-NGO cladding as shell, the effective thickness is5⁶nm, with Ptnanoparticles which particle size is2³nm mixed therein, it is core/shell structure onthe degree of three-dimensional space. CO stripping experiments showed that most ofthe Pt nanocrystals are in CeO₂and r-NGO border region, and a small part Pt in ther-NGO shell interior and surface position.The electrochemically active area （ESA） of the Pt/CeO₂/r-NGO catalyst is up to100.7m2g-1（Pt）, it shows remarkable catalytic activity, as the anode catalyst. For formicacid anodizing, its being swept PIpeak is3times of general Pt/C catalyst, and PIIpeakis nearly4times of general Pt/C catalyst. For methanol anodizing, its being swept peaksis2.65times of general Pt/C catalyst. In addition, after2000segment cycles, the ESA ofthe Pt/CeO₂/r-NGO catalyst maintains84.4%of the original. The excellentelectrochemical properties benefit from the strong support of the rare earth oxide CeO₂and r-NGO material, the Nucleus-structured CeO₂microspheres greatly reduce theeffect of the corrosion of the carrier, and the "through put" effect of the lattice oxygen inthe structure promotes the CO oxidation, the CO tolerance of catalyst is improved, thethin carbon layer shell of r-NGO compensate the disadvantage of CeO₂that poorconductivity, and promoted the electron transfer rate in three phase of Pt, CeO₂, r-NGO.