Fig. 3: Synthesis and structural characterization of samples.

a Schematic of the preparation method of NiM-LDHs/GF (M=V, Mn, Fe, Co, Cu). b, c SEM images morphology of Ni0.67V0.33-LDH/GF, inset of (b) is the corresponding low-magnification SEM images. d, e TEM, f HRTEM, and g Elemental mapping of Ni0.67V0.33-LDH/GF, inset of (f) is the corresponding selected area electron diffraction (SAED) image. h XRD, XPS spectra of i Ni 2p and j V 2p for Ni0.67V0.33-LDH and β-Ni(OH)2.