“…There were numerous attractive applications of NiO in a variety of fields including catalysts [2], gas sensors [3], dye-sensitized solar cell [4,5], lithium ion battery [6], supercapacitor electrodes [7], and so on. Recently, NiO showed excellent resistive switching behavior and could be expected to find potential use in nonvolatile memorles [8,9]. In addition, nanocrystalline NiO with high surface area possessed better properties than that with low surface area.…”