Fig. 2.

Performance of Sr₂GaCoO₅ towards oxygen evolution in neutral-pH. a Linear sweep voltammogram of Sr₂GaCoO₅, commercial IrO₂ and blank electrode with only glassy carbon and ink. All current densities were normalized based on the surface area measured in Brunauer–Emmett–Teller analysis, 8.4 m²·g⁻¹ for Sr₂GaCoO₅ and 32.0 m² g⁻¹ for IrO₂. The current for the blank electrode was normalized to the surface area of Sr₂GaCoO₅ loaded on the electrode. b Tafel plot of Sr₂GaCoO₅ and commercial IrO₂. The data is fitted with the equation $i=i_0\exp \left[\alpha \left(V-V_0\right)\right]$, where $i_0$ is the preexponential factor and V₀ is the equilibrium voltage. c Cyclic voltammetry of Sr₂GaCoO₅. No appreciable change was observed during 200 repeated scans. d Galvanostatic experiments at constant current densities. The overpotentials at constant current densities of 20, 50, and 100 μA·cm⁻²_oxide was stabilized at 0.28, 0.30 and 0.32 V, respectively. e Potentiostatic experiments at constant voltages. The capacity retention after five hours of operation was 94–96%. f Comparison of the overpotentials for Sr₂GaCoO₅, Sr₂AlCoO₅, and IrO₂ at the same current densities in pH 7 and pH 13 solutions