氫氧燃料電池薄膜電極(Membrane Electrode Assembly, MEA)的觸媒層是同時發生反應物質傳、電化學反應、排水的場所，因此觸媒層是決定薄膜電極性能的重要核心。由於陰極的電化學反應產物會有水，因此陰極的觸媒層結構不僅需要讓氧氣能順利擴散至觸媒層與觸媒產生反應，還得具備適度的排水功能避免觸媒層因水淹導致微孔被堵塞，造成氧氣擴散不進去，導致高電流密度下的性能損失。多孔且空間空隙大的觸媒層結構被視為一個可以同時能讓反應物氣體順利擴散至觸媒層內部也能同時將反應的水及時排出的陰極觸媒層結構。
本研究利用超音波噴塗機進行觸媒層塗佈，透過調整載台的真空度(500mmHg、600mmHg、650mmHg)、噴嘴頻率(48kHz、120kHz)以及調控加熱台溫度(60 °C - 110 °C)來獲得不同的多孔觸媒層結構。載台的真空度控制的是薄膜形變的能力，觸媒沉積的位置隨著薄膜皺褶程度不同而形成高低起伏的觸媒層結構，使用較低真空度的500以及600mmHg薄膜電極在高電流密度表現較高真空度的650mmHg薄膜電極高100Ma/cm2。噴嘴頻率所控制的是噴出液滴的大小，使用48kHz頻率的噴嘴所獲得的孔洞直徑約10-35μm，而120kHz頻率的噴嘴獲得的孔洞為3-8μm，因此觸媒層的堆疊結構與孔徑分布大小會截然不同，使用48kHz頻率噴嘴的薄膜電極會獲得起伏程度較高的觸媒層結構，使用120kHz噴嘴的薄膜電極則有明顯白金使用率降低的問題。加熱台的溫度控制的是液滴揮發速度。在加熱台60 °C以及70 °C的情況下，由於揮發速度慢在噴塗初期會形成較連續的液膜，導致乾燥後形成孔隙度較低的觸媒層。80°C -110°C時則在初期即因咖啡圈效應(Coffee-ring Effect)而堆疊形成具孔洞的觸媒層。最終的孔徑分析，60 °C及80°C分別獲得12μm及16μm的平均直徑。在燃料電池單電池測試條件下，80 °C製作的MEA可以獲得1520mA的極限電流密度，而在60°C的MEA僅獲得1350mA的極限電流密度。
本研究通過對薄膜電極內部結構優化的工程(真空載台、噴嘴、加熱載台)，最大限度地減少傳質阻力，從而為觸媒層中發生的電化學反應找出最佳操作條件。

The catalyst layer of the membrane electrode assemble (MEA) is a place where the multiphase transport process, electrochemical reactions, and water repelling occur simultaneously, therefore the structure of the catalyst layer is important core for the performance of the MEA. Since the electrochemical reaction product of the cathode is water, the catalyst layer structure of the cathode not only needs to allow oxygen to diffuse into the catalyst layer and react with the catalyst, but also has the drainage function to avoid flooding of the catalyst layer, resulting in performance loss under high current density. Therefore, the porous catalyst layer and void structure is regarded as a catalyst layer structure that can diffuse the reactant gas into the catalyst layer and repel the water balance environment. In this work, an ultrasonic spray coater was used to coat the catalyst layer.
To obtain different porous and void catalyst layer structures, select the different vacuum value plate (500,600,650mmHg), nozzle frequency (48, 120 kHz) and temperature of the heating plate (60°C-110°C). Vacuum plate controls the membrane deformation when touch with solvent. Deposition will follow the wrinkle of membrane, and form the rough catalyst layer. During high current density area ,500-MEA and 600-MEA is 100mA/cm2 larger than 650-MEA。The nozzle frequency controls the size of the droplets ejected. The diameter of the pore obtained by the nozzle with the 48kHz frequency is about 10-35μm, and the pore obtained by the nozzle with the frequency of 120kHz is 3-8μm, so the stacked structure and porosity of the catalyst layer will be very different. The 48kHz-MEA would get rough catalyst layer and 120kHz-MEA would get uniform catalyst layer and another issue is low Pt utilization. The heating plate temperature controls the evaporation rate of the droplets. At 60°C and 70°C MEA, a more continuous liquid film will be formed at the initial stage of spraying due to the slow evaporation rate, resulting in the formation of a less porous catalyst after drying. At 80°C -110°C MEA, there are pores caused by the coffee-ring effect in the initial stage. The diameter of the pore obtain by 60°C-MEA and 80°C-MEA is 12μm and 16μm. During high current density area , 60°C -MEA and 80°C -MEA shows that 1520mA/cm2 and 1350mA/cm2 .
In this study, with optimized engineering of the electrode structure, the mass transfer resistances can be minimized to give the best operating conditions for electrochemical reactions to occur in the catalyst layers.

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