Preparation and Performance Research of Ionic Membrane Complexes with Metal Particles
|School||Anhui University of Technology|
|Keywords||proton exchange membrane TiO2 thermal stability surface treatment fuelcell thermal degradation kinetics|
Using domestic perfluorinated sulfonic acid ion-exchange membrane as matrix doped TiO2particles to prepare composite membrane by the sol-gel method and cross-linking method, which were applied to the proton exchange membrane fuel cell. FTIR, XRD and DMA methods were used to characterize the composite membrane, the temperature resistance of composite membrane compared with original membrane was investigated by using the TGA method, the possible thermal degradation kinetic equation and its mechanism were deduced.The proton conductivity, ion exchange equivalent, swelling ratio and water absorption were measured. The oxidation resistance of the composite membrane was determined.The strong absorption peaks of the Ti-O bond appeared in2953cm-1and1454cm-1in the FTIR spectra, we can see a strong diffraction peak of the Ti-O bond at20near14°in the XRD pattern. The water absorption, swelling ratio, ion exchange equivalent and conductivity for the modified membrane are a certain extent improved. The water absorption of the composite membrane is up to44.68%in the operating temperature at80℃, the conductivity of modified membrane and un-modified are1.15×10-4S·cm-1and8.34×10-6S·cm-1respectively.By means of a constant temperature of200℃storage,3%hydrogen peroxide and1%the Fenton reagent oxidation test, respectively, determination of the original film and the TiO2composite membrane antioxidant capacity showed that the impact on the molecular chain-SO3-and C-O-C group on the membrane is close, a greater impact on the chain-CF2-group is found, before and after membrane molecules are modified.TGA results show that the thermal degradation process of the original film is divided into two phases, the first peak temperature is between350and400℃, the second peak temperature is between470and530℃the thermal decomposition of TiO2composite film is only a thermo-gravimetric stage, the peak temperature is between490and550℃. When decomposition rate a is greater than8%,the heating rate and the decomposition rate are the same, the decomposition temperature and the peak temperature of the modified membrane are moved to the high-temperature region.The thermal degradation kinetic parameters and mechanism function were obtained by analyzing the non-isothermal kinetic data of the modified and un-modified film, and by using the Kissinger, Flynn-Wall-Ozawa, Starink, Friedman, Achar and Coats-Redfern methods. Before modified, the thermal degradation process was controlled by the P1(Power Law) mechanism in1st stage, the apparent activation energy E is145.16kJ·mol-1, the pre-exponential factor A is1.79×1011min-1, the mechanism function f (α) and g (α) are the1and a respectively.The thermal degradation process was controlled by the3D (Z-L-T function) mechanism in2nd stage, the apparent activation energy E is187.19kJ·mol-1, the pre-exponential factor A is3.33×1011min-1, the mechanism function f (α) and g (α) are3/2(1-α)4/3[(1-α)-1/3-1]-1and [(1-α)-1/3-1]2respectively.The thermal degradation of the TiO2composite proton exchange membrane was controlled by F1mechanism, the apparent activation energy E is193.39kJ·mol-1, the factor A is6.81×1012min-1, the mechanism function f (α) and g (α) is1-α and-ln(1-α) respectively. The calculation results by using various methods show that the average apparent activation energy increased23.01kJ·mol-1for modified membrane than un-modified.