Fig. 3

Evaluation of the formed IrO_x phase(s) and SrCo_0.9Ir_0.1O_3−δ bulk chemical states. a Ir_4f X-ray photoelectron spectroscopy (XPS) for IrO₂, m-SrIrO₃, and SrCo_0.9Ir_0.1O_3−δ before and after the electrochemical tests. b The cyclic voltammetry (CV) curves recorded at the 1st, 1000th, 5000th, and 10,000th cycles for SrCo_0.9Ir_0.1O_3−δ, m-SrIrO₃, and Ir metal in a 0.1 M HClO₄ electrolyte. The cycles presented are collected at a scan rate of 100 mV s⁻¹. For the intermediate cycles, a scan rate of 1 V s⁻¹ is applied. c X-ray absorption near edge structure (XANES) and 1st derivative XANES spectra (inset) of LaCoO₃ and SrCo_0.9Ir_0.1O_3−δ measured at Co K-edge. d XANES spectra of IrO₂, m-SrIrO₃, and SrCo_0.9Ir_0.1O_3−δ measured at Ir L_III-edge. e k³-weighted Co K-edge Extended X-Ray Absorption Fine Structure (EXAFS) spectra of LaCoO₃ and SrCo_0.9Ir_0.1O_3−δ. f k³-weighted Ir L_III-edge EXAFS spectra of IrO₂, m-SrIrO₃, and SrCo_0.9Ir_0.1O_3−δ