| Alkaline direct methanol fuel cell(ADMFC) becomes the focus of researchers attention due to its high energy density and rich source. The traditional ADMFC exists lot of problems, such as high cost, easy to poisoning and inferior stability of the catalyst. So the main direction of the research in ADMFC catalyst is reducing cost and improving the catalytic activity of catalysts. Based on the above issues, we use the optimizing three phase transfer method to synthesize PdPt based catalyst, and PdPt based catalysts for methanol oxidation reaction in an alkaline environment has also been implemented in this thesis.This paper improves the preparation method of Cu@PdPt core-shell catalyst, shell precursor ratio and other key parameters which could influence the performance of catalyst. In addition, the different process parameters(reducing agent and intermediate phase) have been optimized for higher catalysis activity. The performance test for Cu@PdPt core-shell catalyst in alkaline medium is researched, and the mechanism of the activity improvement has also been analyzed. The results show that the choice of reducing agents and the existence of the intermediate phase can affect the reaction rate during the reduction process of the PdPt precursors, and they change the performance of Cu@PdPt catalysts. Compared with PdPt catalyst, the catalytic activity of Cu@PdPt has been significantly improved, and the main cause of the enhanced performance attribute to the intense electronic interaction between the Cu core and PdPt shell.In order to further verify the core-shell structure catalyst has also been prepared with the three phase transfer method with the Ni cores. The experimental results show that the Ni@PdPt catalysts in the alkaline medium for methanol electrooxidaiton are 3.62 than PdPt alloy catalyst. The results of XPS indicated a strong electronic interaction between Ni and PdPt is the elevated reason of the performance of the Ni@PdPt catalysts. |
PDF Full Text Request