Preparation Of Ternary Electrocatalyst And Its Application In Direct Methanol Fuel Cells

To solve the present environmental pollution and energy crisis problems, many recent efforts have been devoted to developing fuel cell systems, due to their potential applications in providing sustainable and clean power sources. Direct methanol fuel cell(DMFC) has attracted much attention due to its high-energy conversion efficiency, convenient storage, and relatively cheap price and rich source of liquid fuels. However, the catalyst is strongly hindered by several problems such as high cost, poor activity and low poisoning resistance. Therefore, in this thesis, the work has been mainly focused on reducing the cost and improving the performance of the catalysts, through alloying noble Pt or Pd with cheap metals(Cu, Fe, Co, Ni) and anchoring catalysts on supporting materials.Firstly, ternary NiCoPt and NiCoPd nanostructures loaded on carboxylated multiwalled carbon nanotubes(c-MWCNTs) were facilely synthesized. And the electrochemical performance was tested for methanol oxidation reactions(MOR) under the acidic and alkaline media, respectively. The results revealed that ternary catalysts exhibited highly enhanced electrocatalytic activity and improved stability in comparison with those of binary and mono-metallic counterparts. In addition, NiCoPd/c-MWCNTs catalysts also showed the best activity for the oxygen reduction reaction(ORR).Secondly, ternary Cu FePt, NiFePt and CoFePt nanocatalysts anchored on the reduced graphene oxide(rGO) have been facilely synthesized by using NaBH4 as reductant in an ambient one-pot strategy. The electrochemical measurements showed that the ternary catalysts exhibited highest electrocatalytic activity and stability for MOR. It was also found that the introduction of Cu could improve the performance on the CO poisoning tolerance. In addition, CuFePt/rGO catalysts also showed the highest activity and stability for the formic acid oxidation reaction(FAOR).Finally, the electrochemical activity and stability of the dealloyed catalysts were discussed. The dealloyed catalysts were prepared by electrochemical or acid treatment methods. The results showed that the electrochemical activity of the dealloyed catalysts drastically increased, but the stability decreased.