“…Since Switzer and co-workers [19,20] introduced an electrochemical method for the first time as a synthetic route to ceramic films as well as polycrystalline CeO 2 powders, nano-sized metal oxides prepared by an electrochemical method have been an active research area. A number of metal oxides thin films, including ZnO [21,22], zirconium oxide [23], tungsten oxide [24], bismuth oxide [25], Cu 2 O [26] and CuO [27][28][29], have been synthesized via an electrochemical method. Reetz and co-workers [30][31][32][33] proposed a sacrificial anode electrochemical route to synthesize nanometal clusters.…”