Fig. 3: OER performance of py-RuO₂:Zn in acidic media.

a Geometric area and Ru mass normalized LSV curves with 85% iR-correction of py-RuO₂:Zn, py-RuO₂, and c-RuO₂ for OER in 0.5 M H₂SO₄ solution (pH = 0.30 ± 0.01) with O₂ saturation. Solution resistances for iR-correction are 2.8, 2.6, and 4.5 Ω for py-RuO₂:Zn, py-RuO₂, and c-RuO₂, respectively. Mass loadings of Ru metal are 0.52, 0.60, and 0.60 mg cm⁻² for py-RuO₂:Zn, py-RuO₂, and c-RuO₂, respectively. b Geometric area and Ru mass normalized LSV curve of py-RuO₂:Zn for OER under high current density. c Comparisons of OER geometric and mass activities at an overpotential of 300 mV on py-RuO₂:Zn, py-RuO₂, and c-RuO₂. d Tafel plots derived from the LSV curves (solid line) and the steady-state polarization curves (scatters). Values in parentheses were derived from steady-state polarization curves. e Chronopotentiometric stability tests of py-RuO₂:Zn and c-RuO₂ (upper plot: 100 h at 50 mA cm⁻²; middle plot: 1000 h at 10 mA cm⁻²) and mass loss analysis of Ru and corresponding stability number (S-Number) on py-RuO₂:Zn during the stability test determined by ICP-MS (lower plot). Comparison of overpotentials and f Tafel slopes, and g mass activities for py-RuO₂:Zn and other recently reported high performance RuO₂-based OER catalysts.