Fig. 2. (a) 50kX, (b) 250X micrographs of rGO, (c) 50kX and (d) 250X micrographs of rGO:CB, (e) 50kX and (f) 250X micrographs of NirGO3 materials and (g) EDS spectrum of NirGO3.
In the Cs1 spectrum of the XPS survey (Fig. 3(b)), peaks at 285.00, 286.67, and 288.90 eV were related to C=C, C—OH and C=O bonds, respectively. The peaks belonging to O=C/O—Ni and HO—C were observed at 533.04 and 531.56 eV in the Os1 spectrum (Fig. 3(c)), respectively. Furthermore, in the Ni2p spectrum (Fig. 3(d)), two typical peaks at 855.80 and 873.40 eV are referred to as Ni2p3/2 and Ni2p1/2, respectively. Spin-energy separation was calculated as 17.60 eV as the individual indicator for Ni (OH)2 phase (Fig. 3(a)). Besides, satellite signals are defined as two extra peaks at 861.50 and 879.00 eV, which close the Ni2p3/2 and Ni2p1/2. XPS results agree with XRD and FT-IR analyses and indicate that the electrode material of NirGO3 is consisting of rGO and Ni(OH)2.