## 3 Results
### Electrochemical Behavior of Ti Gr. 2 in Presence of Clays
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameters** & **0.5M NaCl** & \begin{tabular}{c} **0.5 M NaCl +** \\ **(1:1) Kao./Mont.** \\ \end{tabular} & \
\begin{tabular}{c} **0.5 M NaCl +** \\ **1000 ppm Kao.** \\ \end{tabular} &
\begin{tabular}{c} **0.5 M NaCl +** \\ **1000 ppm Mont.** \\ \end{tabular} \\ \hline \(i_{0,Tl}\), \(\text{A/m}^{2}\) & \(1.99\times 10^{-9}\) & \(5.13\times 10^{-2}\) & \(9.60\times 10^{-3}\) & \(7.20\times 10^{-3}\) \\ \(t_{Ti}\), \(\text{mV/dec}\) & \(238\) & \(231\),\(629\) & \(159\),\(369\) & \(243\),\(684\) \\ \(i_{0,O_{2}}\), \(\text{A/m}^{2}\) & \(-2.03\times 10^{-6}\) & \(-7.15\times 10^{-6}\) & \(-7.57\times 10^{-7}\) & \(-1.83\times 10^{-7}\) \\ \(t_{O_{2}}\), \(\text{mV/dec}\) & \(-168\) & \(-207\) & \(-171\) & \(-165\) \\ \(i_{l,O_{2}}\), \(\text{A/m}^{2}\) & \(-13.68\) & \(-8.38\) & \(-4.76\) & \(-3.79\) \\ \(i_{0,H_{2}}\), \(\text{A/m}^{2}\) & \(-1.46\times 10^{-2}\) & \(-1.44\times 10^{-2}\) & \(-1.23\times 10^{-2}\) & \(-3.54\times 10^{-3}\) \\ \(t_{H_{2}}\), \(\text{mV/dec}\) & \(-217\) & \(-247\) & \(-256\) & \(-253\) \\ \(E_{corr}\), \(\text{mV/SHE}\) & \(-7\) & \(-48\) & \(27\) & \(-6\) \\ \(i_{corr}\), \(\text{A/m}^{2}\) & \(0.0693\) & \(0.0522\) & \(0.0098\) & \(0.0073\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Kinetic and corrosion parameters for Ti Gr. 2 electrode in NaCl and clay slurries, obtained from applying the superposition model. Figure 6: Polarization (**a**) and Tafel (**b**) curves for Ti Gr. 2 in contact with 0.5 M NaCl and slurry of clays. Experimental curve (dotted line) and fitted curve (line) obtained from the superposition model. of the clay slurry, which are in turn consistent with the electroflotation recoveries for clays. Thus, it is possible to indicate that the values signify enhanced catalytic activity and greater efficiency in reducing molecular oxygen within a pure salt solution. Furthermore, the kinetic parameters show an interesting alteration when the Ti Gr. 2 is immersed in clays, which could be related to variations in the cell current during the electroflotation process. As shown in Table 3, the Tafel slope for TOR in a NaCl solution has similar values commonly observed in the literature, ranging around 238 mV/dec [32]. As shown in Figure 6b, from the inversion potential towards anodic direction, the current density follows a planar tendency with the applied potential for tests in the presence of clays, compared to the tendency in a pure NaCl solution where the current density increases with the applied potential. This behavior, along with higher anodic Tafel slope values in the presence of clay slurries, indicates that the Ti Gr. 2 rapidly passivates with the formation of titanium oxides and promotes a good corrosion resistance [45]. Thus, based on this analysis, the exchange current density can be approximated to the passivation current density. The spontaneous passivation of the Ti Gr. 2 electrode is consistent with the current variations during the electroflotation tests. On the other hand, the cathodic kinetic parameter for ORR and HER does not show appreciable variations in clay slurries; however, these kinetic parameters were lower than that determined for a pure NaCl solution. The variations of \(E_{corr}\) for clay slurries have not shown a clear tendency since that it was shifted to cathodic direction for the mixture (1:1) and to anodic direction for singles slurries with respect to \(E_{corr}\) for a pure NaCl solution. These variations are less than \(\pm 85\) mV, which indicates that the clay slurry could affect both anodic and cathodic reactions [46], with a predominance effect on cathodic reactions for the mixture (1:1) slurry. The corrosion rate exhibited by the Ti Gr.