Fig. 2

Characterization of the as-prepared MNS. a The XRD pattern of the as-prepared MNS compared with the standard data of maghemite Fe₂O₃, NiO, and nickel. b XPS survey spectrum and XPS spectra in Ni 2p, Fe 2p, and O 1s regions for the as-prepared MNS. c SEM image and (d) corresponding EDX elemental mapping images for the as-prepared MNS. e The TEM image, f the HRTEM image and g the SAED pattern of the as-prepared MNS