Fig. 4: Thermodynamic analysis of oxidation process.
From: Theoretical insights on potential-dependent oxidation behaviors and antioxidant strategies of MXenes
The energies of the MXene slab (blue) and two oxidation states (*OH, yellow; *O, red) versus the electrode potential, (a) V2CO2 and (c) Ti3C2O2. Symbols represent computationally derived values, and lines are fitted using a quadratic function (\(E\left(U\right)=-\frac{1}{2}C{\left(U- {U}_{{PZC}}\right)}^{2}+ {E}_{{PZC}}\)). The potential of zero charge is marked with the short line. The free energies of the system as a function of potential, (b) V2CO2 and (d) Ti3C2O2. Based on the free energy equation (\({G}_{U}\left({slab}\right)+G({H}_{2}O)\to {G}_{U}( * \, {OH})+\frac{1}{2}G\left({H}_{2}\right)+{{eU}}_{{SHE}}\to {G}_{U}( * \, O)+ G\left({H}_{2}\right)+2{{eU}}_{{SHE}}\)), the x-coordinate of the first intersection between the stable state (blue) and the oxidation states (*OH, yellow; *O, red) is marked as the oxidation potential with a green dashed line.
