Fig. 2: Structural characterizations and function analysis.

a XRD patterns of CoCr₂O₄ and Pd-CoCr₂O₄. b, c HRTEM images of Pd-CoCr₂O₄ with different resolutions. High-resolution XPS spectra of d Pd 3 d, (e) Co 2p, and f Cr 2p. g NH₃-TPD of Pd-CoCr₂O₄, Pd-Cr₂O₃, Pd-Co₃O₄, and Pd. h CV curves obtained at a scan rate of 90 mV s^–1 for Pd-CoCr₂O₄, Pd-Cr₂O₃, Pd-Co₃O₄, and Pd in 1 M KOH. i Relationship between current density and scan rate. j PZCs of Pd-CoCr₂O₄, Pd-Cr₂O₃, Pd-Co₃O₄, and Pd in 0 (100 mM KCl), 20, 40, 60, 80, 100 mmol KOH solutions. k Bode plots of Pd-CoCr₂O₄ in 1 M KOH under different potentials. l Plots of C_φ vs. potential for Pd-CoCr₂O₄, Pd-Cr₂O₃, Pd-Co₃O₄, and Pd in 1 M KOH.