Synthesis And Characterizations Of Pdcu Bimetal Catalysts And It’s Formic Acid Oxidation Activity In Fuel Cells

Fuel cells offer us an ideal way to gain power efficiently without pollution. The fuel was directly used to gain electric power converting from chemical energy through an electric chemical process without combustion. As the process is not restricted by Carnot cycle, the efficiency can be improved greatly. And little pollution would be produced. In fuel cells main catalysts are metals, especially noble metals, like Pd or Pt. But the costs of the catalysts are so high that it cannot be widely used. To lower the costs and improve the activity of the formic acid-oxidation catalysts in fuel cells, in this paper, we produce some PdCu catalysts. XRD, TEM, HRTEM, and electrochemical measurements of CV and CA are done to characterize the morphology, structure and electrochemical activity.(1) PdCu nanoparticles are synthesized through a liquid phase reduction method. Some capping agent is used to control the crystal morphology. Judged by TEM, we can see the particle morphology. Without the capping agent, nanoparticles of sphere-like with size of about20nm are obtained. With the capping agent, nanocubes with size of about10nm are obtained.(2) PdCu alloys with different molecular ratio are synthesized through liquid phase reduction method. These alloys are loaded onto carbon black and formed PdCu/C catalysts. TEM shows that the size of the sphere-like particles is around8nm. And XRD data shows that the PdCu alloy has an fcc structure. Electrochemical measurements data shows that the PdCu/C catalysts are more active than Pd/C catalyst toward formic acid oxidation.(3) Pd coated Cu nanowires are synthesized in organic solution with a two step method. The derived Cu@Pd nanowires are loaded onto carbon black and formed Cu@Pd/C catalyst. Detail characterization (XRD, TEM and HAADF-STEM) results confirm that the as prepared nanowires have a Cu@Pd core-shell structure with enlarged surface areas. Electrochemical measurements (cyclic voltammetry and chronoamperometry measurements) data shows that the as prepared Cu@Pd catalyst can significantly improve the electrocatalytic activity and stability of Pd component toward formic acid oxidation.