Fig. 2: Morphology and structural characterizations of typical samples.

a, b FESEM images of the Ir-FeCoOx/BiVO4 with different magnification times. c–i Structural characterizations of the FeCoOx/BiVO4 sample together with references: c Normalized Fe K-edge XANES μ(E) spectra. d Normalized Co K-edge XANES μ(E) spectra. e Fe K-edge and Co K-edge radial distance χ(R) space spectra. f Fourier-transformed (FT)-Extended X-ray absorption fine structure (EXAFS) fitting curves at R space of Fe K-edge. g FT-EXAFS fitting curves at R space of Co K-edge. h Fe K-edge 3D contour wavelet transform. i Co K-edge 3D contour wavelet transform.