fig2

Figure 2. (A-C) SEM images of NiCoON/NF host. (D) Low-magnification and (E) high-resolution TEM images of NiCoON/NF. (F) XRD pattern of NiCoON/NF. (G) Ni 2p, (H) O 1s and (I) N 1s XPS spectra of NiCoON/NF. SEM: Scanning electron microscopy; TEM: transmission electron microscopy; XRD: X-ray diffraction; XPS: X-ray photoelectron spectroscopy.