Preparation Of CeO₂：Nanoparticles And The Catalytic Action On Oxidation Of Methanol

Direct Methanol Fuel Cell （DMFC） is a kind of fuel cell whichdirectly uses methanol as fuel. Compared with other fuel cells, DMFC isenvironment-friendly. Furthermore, the volume of DMFC is smaller andthe theoretical energy is higher. As a result, DMFC is proposed to be akind of promising power source. The anode catalyst of DMFC is usuallyplatinum （Pt）, but Pt is easily poisoned by CO-like intermediatesproduced during methanol electro-oxidation. In this study, CeO₂was usedto decomposite CO-like intermediates, prevent the poisoning of Pt andimprove the catalytic activity. Firstly, CeO₂nanoparticles were preparedby the facile precipitation using NaOH as precipitant and the product wascharacterized by XRD, TEM, TG-DTA and XPS. The effect of theconcentration of NaOH solution on the formation of the CeO₂was alsostudied. The results showed that the particle size of the CeO₂was about3nm. When raising the concentration of NaOH solution, CeO₂nanowiresappeared in the obtained products.CeO₂nanoparticles deposited on CNTs were also synthesized by thefacile precipitation using NaOH as precipitant in presence of CNTs.The morphologies of CeO₂/CNTs composite was characterized by XRD, TEM,TG-DTA and FI-IR. The results showed that CeO₂nanoparticles wereuniformly packed with the surface of the CNTs with uniform sizes ofabout2-3nm.CeO₂nanoparticles and CeO₂/CNTs composite were mixed withPt/CNTs catalyst which was prepared by microwave process usingethylene glycol as reductant. The catalytic activity of the mixed catalyststowards methanol electro-oxidation process and the decomposition ofCO-like intermediate were characterized by cyclic voltammetry andchronoamperometry. The result showed that the catalytic activity ofPt/CNTs towards oxidation of methanol and decomposition of CO-likeintermediate were improved by mixing CeO₂nanoparticles andCeO₂/CNTs composite material. The appropriate amount of CeO₂nanoparticles was30wt%and the appropriate loading rate of CeO₂/CNTscomposite material was40%.