An environment-friendly fabrication of nano-Co3O4 coating by aqueous electrophoretic deposition

Co 3 O 4 coating is one of most studied transition metal oxide due to its wide application in many fields such as gas sensors, electrochromic thin films, supercapacitors, and solar selective absorber. Aqueous electrophoretic deposition (EPD), which is considered as a cost-effective and environment-friendly coating technology, was successfully employed in preparing nano-Co 3 O 4 coating in this study. For the EPD process with the solid loading of 1 g L −1 , 2.0 mM nitric acid was employed as suitable additive and 5 V was employed as deposition voltage. The prepared nano-Co 3 O 4 coating exhibited good film characteristics, which was proved by scanning electron microscopy (SEM) technology. The result suggests that a rapid preparation of nano-Co 3 O 4 coating in aqueous dispersion system can be easily accomplished. Moreover, the optimum concentrations of the added nitric acid would increase with the solid loading of Co 3 O 4 nanoparticle, but the growth rate of the former was obviously lower than that of the latter.