Fig. 1. (a) Raman shift spectra, (b) XRD patterns (# refers to rGO crystalline signals, * refers to Ni(OH)2 crystalline signals) and (c) FT-IR spectra of electrode materials.
In the EDS spectrum (Fig. 2(g)) of Ni-rGO, as expected, there is a Ni atom in the structure accompanied by C and O. Although Ni(NO3)2 was used as the reactant at the beginning of the reaction, the absence of the signal of the N atom in the spectrum indicates that the starting material is fully reacted, and as a result of this process, oxide/hydroxide derivatives of Ni are eventually formed.