Fig. 3
XPS and XANES characterization of NiCo2S4 and N-NiCo2S4. XPS core-level spectra of a Co 2p, c Ni 2p, and e S 2p for NiCo2S4 (blue) and N–NiCo2S4 (red). XANES spectra of b Co L-edge, d Ni L-edge, and f S L-edge for NiCo2S4 (blue) and N–NiCo2S4 (red)
