(a) Schematic illustration of NCS/VOG/CNF film preparation. SEM images of (b) CNF, (c) EOG/CNF, (d) NCO/EOG/CNF, and (e) NCS/EOG/CNF. TEM images of (f) CNF/EOG, (g) NCO/EOG/CNF, and (h) NCS/EOG/CNF. (i) XRD patterns of different samples. High-resolution XPS spectrum of (j) Ni 2p and (k) Co 2p peaks from the NCS/EOG/CNF sample.