Fig. 5 demonstrates the sensor performances with identical Pt loading on their electrodes as the function of %BAC and examines the linearity response ofdifferent sensors by altering the electrode’s catalyst loading. The peak current density of different catalyst loaded sensors is shown in Fig. 5(a). The increase of Pt/C loading from 10% to 40% raised the peak current densities, which was expected due to an increase in the catalyst loading on electrodes. Increasing the catalystloading increases the active sites resulting in activation polarizations reduction leading to an increasing in generated current densities. In addition to the output current density magnitude and sensors response linearity,the sensitivity of sensors is another important factor for MEAs characterization. The sensor sensitivity would be obtained by the slope of calibration curves shown in Fig. 5(a). The current density sensitivity factors (slope of calibration curves) of identical electrode sensors were calculated with respectto total mass of Ptloaded in each sensors GDEs. Table 2 listed the sensitivity values for identical sensors.