fig2
Figure 2. Chemical states and coordination environment of Ni1/NC. (A) Ni 2p and (B) N 1s XPS spectra of samples; (C) Ni K-edge XANES, (D) FT-EXAFS, and (E) WT for the EXAFS signal of Ni1/NC and references. NC: Nitrogen-doped carbon; XPS: X-ray photoelectron spectroscopy; XANES: X-ray absorption near edge structure; FT-EXAFS: Fourier transformed-extended X-ray absorption fine structure; WT: wavelet transform.
