Electrochemical fabrication of copper microcolumns and their coating of nano ZnO

Coating feasibility of nano-ZnO on a copper micro-column was of interest in this work. The copper micro-columns, in an average diameter of 80 μm, were prepared from a bath of copper sulfate by a novel method of real-time image-monitoring micro-anode guided continuous electroplating. The electrochemical coating of nano-ZnO was carried out with a three-electrode electroplating system. Surface morphology of the nano-coating influenced by the experimental parameters such as deposition potential, bath composition and deposition time was investigated. Examination through field emission scanning electron microscope, we found that electrochemical coating of nano-ZnO was feasible from a bath containing 2 mM zinc sulfate and 20 mM hydrogen peroxide at a potential of -0.96 V (vs. Ag/AgCl) for 20 minutes. Analysis of photoluminescence spectroscopy of the nano-ZnO coating indicated that an excitation with 330 nm leading to two intense emission peaks at 387 nm and 396 nm. Under adequate control of electrochemical condition, the nano-ZnO coating revealed a layer structure accumulated by ZnO nanorods which indicated a huge specific area to be considered as a potential candidate for gas-sensing materials.