| Direct methanol fuel cell (DMFC) is an electrochemical device that converts chemical energy into electrical energy. It has many advantages, such as high specific energy density of fuel, simple system structure, convenient refueling and start quickly, etc. It is a very promising energy sources. But if you want to make it into a large scale commercial application, there exist some problems. First, the methanol oxidation process is a dynamic slow reaction, it hinders the energy efficiency of DMFC; the other problem is when in the running process of DMFC, the ruthenium elements in PtRu/C catalysts could gradually loss over time.We use ethylene glycol reduction method, making the H2PtCl6.6H2O and RuCl3.xH2O reacts, and load them on Vulcan XC-72R carbon, finally we get PtRu catalyst with 40% metal loads. By means of XRD test we can find its platinum (fcc) structure of characteristics diffraction peak; as for TEM characterization, we find that the catalyst metal particle distribute uniformly on the carbon carrier, no phenomenon of reunion, and catalyst particle size distribution range is between 2?3 nm.Conducting accelerated aging experiment for PtRu catalyst with atomic ratio of 1:1, with high potential CV scanning, the activity of catalyst shows the law of monotone decrease, the reaction resistance is becoming bigger. Simulation calculation for that set of data, found that the four kinds of dynamics model can all successfully simulate the IE curve change rule, but only the VCS-Frumkin/Temkin mechanism can well simulate the change of electrochemical impedance spectroscopy.As for the results of catalyst aging experiment, we have preparated several different proportion of catalysts with ruthenium content gradually reducing, simulating ruthenium content loss in the accelerated aging experiments. We find the same changing rule with catalyst accelerated aging experiment. Using the VCS-Frumkin/Temkin mechanism can successfully simulate the change of total harmonic distortion spectrum. |
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