Throughout this paper, all graphical figures regarding the kinetics of the catalysts are represented by MEA graphs. More significantly, it has brought to attention the insufficient data on the MEA tests and the lack of reliable, scalable synthesis methods that measure different catalysts. Still, more efforts are devoted to the performance of catalysts at an RDE level . However, the importance of MEA tests cannot be ignored. First, mass transfer resistance is largely eliminated in RDE measurements, but because it is one of the most critical concepts that impact the fuel cell's kinetics, it cannot be overlooked. Second, MEA tests have a triple-access (gas-liquid-solid) requirement, allowing them to minimize the utilization efficiency of the catalyst at active sites. Third, the concentration of O 2 in RDE tests is extremely low but high for MEA tests. Therefore, RDE tests have seen limitations in challenging thermal, gas, and water management issues. Lastly, MEA allows a test on a more complex fuel cell system due to its specialized equipment than that of RDE . Therefore, more investigations were focused on MEA testing so that researchers could gain more insightful results for catalysts operating through fuel cells.