Figure 3 Chemical state and coordination structure of SA-Cu-NC (A) X-ray photoelectron spectroscopy (XPS) Cu 2p spectrum of SA-Cu-NC. (B) Normalized Cu K-edge X-ray absorption near-edge structure (XANES) spectra of SA-Cu-NC and reference samples. (C) k 3 -weight Fourier transform extended X-ray absorption fine structure (FT-EXAFS) spectra of SA-Cu-NC and reference samples. (D) EXAFS R-space fitting curve of SA-Cu-NC. (E) Wavelet transform (WT)-EXAFS spectrum of SA-Cu-NC. (F) Wavelet transform (WT)-EXAFS spectrum of Cu foil.