Curves presented in the Figure 8 clearly show that obtained electrocatalysts are very diverse regarding the properties of their active centres and therefore, their electrochemical activity. Thermal treatment of systems with supported hexachloroplatinic acid has a deep influence on the final form of the metal (its oxidation state). The various nature of redox processes manifesting in different shapes of voltammetric curves which makes them difficult to compare. To simplify that, a ΔI parameter was introduced. Its value is equal to the amplitude of oxidation and reduction current (Eq. 1):