Fig. 3

Electrocatalytic properties for OER of 6H-SrIrO₃. a Polarization curves of 6H-SrIrO₃ and IrO₂ in 0.5 M H₂SO₄ solution with 85% iR-compensations. The current densities are normalized by the geometric area. b Comparison of mass activity, normalized by the mass of iridium at 1.525 V vs. RHE, of 6H-SrIrO₃, IrO₂, 3C-SrIrO₃, and some Ir-containing catalysts reported recently. The error bar represents standard deviation based on five measurements. c Chronopotentiometric curves for OER in the presence of 6H-SrIrO₃ and 3C-SrIrO₃ in 0.5 M H₂SO₄ solution at 10 mA cm⁻²_geo (without iR compensations). d Percentage of total Sr content leached (or deviated from the stoichiometry) in the solution after 30 h-long catalytic stability test in the presence of 6H-SrIrO₃ and 3C-SrIrO₃. e, f HRTEM images for 6H-SrIrO₃ and 3C-SrIrO₃ after 30 h-long catalytic stability test. Scale bars, 5 nm