Electrodeposition of Copper Doped ZnO Nanotubes and Its Impact on Photoelectrocatalytic Property of ZnO Nanostructure in Improving Photoelectrochemical Water Splitting

- The ZnO nanorods, ZnO nanotubes, and Cu -doped ZnO nanotube photoanodes were electro-synthesized to improve the photoelectrochemical water -splitting performance. The structural, optical, morphologic, and photoelectrocatalytic properties of the prepared samples were investigated. UV -visible results show Cu -doped ZnO nanotube photoanode extends the visible light absorption and reduces the band gap. Mott -Schottky analysis displays that the Cudoped ZnO nanotube sample has higher electron density than other samples. Nyquist plots indicate that Cu doping reduces the charge transfer resistance and improves charge transfer. By comparing the LSV voltammograms, it was found that Cu -doped ZnO nanotube photoelectrode has a maximum photocurrent density of 78.3 mu A/cm2 at 1.6 V vs. RHE. While the value of photocurrent density obtained for pure ZnO nanorods sample is 9.6 mu A/cm2 at 1.6 V vs. RHE. Due to the role of Cu in reducing the band gap and reducing the charge recombination rate, Cu doping enhances the photoelectrochemical efficiency of the ZnO nanotube.