Also, an examination of the capacitive region (0.0 to 0.9 vs RHE) of the catalyst systems (FeBH, Further, using the slope 𝑗 𝑐𝑎𝑝 vs. 𝜗, 𝐶 𝑑𝑙 , the corresponding ECSA values were found to be in the order of FeBH > FeAH > FeMC > FePM > FeCT as shown in Fig. ) and mentioned in Table . Also, the ESCA values of the FeAH, FeMC, FePM, and FeCT catalyst systems are in close agreement with the order of the (k). This highlights the role of ESCA over the total area for surface adsorption. A similar observation was also reported in our previous study of ZnO sheets. However, the higher current density and higher ECSA value for FeBH have not shown agreement with its observed (k). This disagreement in the case of FeBH highlights the parallel role of other electronic and material characteristics. Also, from the Nyquist plots (Fig. ), a general observation suggests that the lower Rct values are associated with a (k), reflecting the ease of charge (e -) transfer with the low (Rct). However, the significant deviation from this in the case of FeBH can be ascribed to its structural differences from other catalysts. Further, from Fig. (b), representing the Bode-plot, it can be observed that all the samples other than FeBH at a high-frequency region, behave almost similarly with phase angle in the range of 80-90 degrees. This indicates a similar lifetime 𝜏 = 1/2𝜋𝑓𝑐 of charge carriers and dynamics. However, FeBH shows that it acts as a resistor (phase angle zero)