The Preparation Of Cerium-based Oxides And The Performance Of Methanol Electrooxidation

The anode catalyst of direct methanol fuel cell(DMFC)exhibits some problems,such as Pt nanoparticles poisoning and support corrosion.Introducing CeO2 into the DMFC anode catalyst can effectively alleviate the above problems,but it still can not meet the performance requirements of commercialization.As a support component,the performance of CeO2 needs further improvement.Base on this point,CeO2 nanorods,Cu-doped CeO2 and CeO2-CuO composite nanospheres were prepared in this paper to improve the performance of CeO2,the effects on electrochemical oxidation of methanol with these three kinds of ceria-based oxides were also studied by subsequent electrochemical tests.In order to determine the optimal reaction conditions of preparing CeO2 nanorods,the influences of the hydrothermal reaction conditions and cerium species on the morphology were studied.According to the result,the suitable reaction conditions to prepare CeO2 nanorods were identified with CeCl3·7H2O as cerium source,hydrothermal reaction at 140? for 48 h.The CeO2 nanorods prepared in this paper were about 150 nm at length with a diameter of about 10 nm.The results of electrochemical tests show that the electrochemical active area of Pt/CeO2nanorodsa/C catalyst is 85.17 m2 g-1,and the current density of electrochemical oxidation of methanol is 435.65 mA mg-1,The catalyst shows good resistance to CO poisoning and electrochemical stability.In order to determine the optimal doping amount of Cu.The performances of Pt/Ce1-xCuxO2/CNTs for electrochemical oxidation of methanol with different doping amount of Cu were studied.The results show that the catalyst has the best performance when molar ratio of Ce and Cu is 4:1.Compare the electrochemical properties of Pt/Ce0.8Cu0.2O2/CNTs with Pt/CeO2/CNTs and Pt/CNTs by electrochemical tests,the results show that Pt/Ce0.8Cu0.2O2/CNTs has the best performance for electrochemical oxidation of methanol,its current density is 638.5 mA mg-1 while with a good resistance to CO poisoning and electrochemical stability.In order to determine the optimal reaction conditions of preparing CeO2-CuO composite nanospheres,the influences of different initial concentration of precursors and the molar ratio of Ce and Cu on the morphology of products were studied.According to the study,the suitable reaction conditions of preparing CeO2-CuO composite nanospheres were identified with the initial concentration of precursors is 0.01 mol L-1,while the molar ratio of Ce and Cu is 1:1.In electrochemical tests,the effect of size of nanospheres on catalyst's performance was studied.The performances for electrochemical oxidation of methanol between Pt/CeO2-CuO/C,Pt/Ce02/C and Pt/C were also researched,and the result shows that CeO2-CuO composite nanoparticles can improve the performance of the catalyst in electrochemical oxidation of methanol.