| Summary: | 碩士 === 明志科技大學 === 化學工程系碩士班 === 106 === In this study, three sets of membrane electrode assemblies were prepared for proton exchange membrane water electrolyzers. The first set of MEAs was prepared by using iridium dioxide IrO2 as the anode catalyst and carbon supported platinum as the cathode catalyst. The anode catalyst loadings were 1.3, 2.6, 3.9, and 5.2 mg/cm2, respectively; while the cathode kept at a constant Pt loading of 0.86 mg/cm2. The second and third sets of MEAs were prepared by using Pt black as the catalysts for both anode and cathode; whereas, the second set MEAs employed 100um PFSA as the proton exchange membrane, and the third set MEAs employed DuPont’s Nafion® N-115 as the proton exchange membrane. For these two sets of MEAs, the catalyst loading of (anode: cathode) were (3.6:3.6), (7.2:3.6), (10.8:3.6), (7.2:7.2), and (10.8:7.2) mg/cm2, respectively.
It is shown that, for the first set of MEAs, IrO2 loading of 2.6mg/cm2 gives the highest water electrolytic performance. Such observations imply that too much catalyst may give rise to the higher resistance of both proton and electron conduction. However, in the case of using Pt black as catalyst, it seems that higher catalyst loading is preferred.
With regards to the temperature effect on the MEA performance, it is shown that most of the MEAs have a peak efficiency at 65℃. Further increase of temperature does not enhance the performance of MEAs; whereas, it may cause quicker degradation of such MEA products.
SEM and XRD were also employed for investigation of the surface and structure properties of the catalyst layers of the MEAs in this study. It is shown that the average particle size of the MEA catalyst is about 5nm.
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