Modulated CeO 2 /ZnO nanoarrays with different structures for enhanced electrochemical performances

It is well known that the electrochemical performances of electrode material as supercapacitor are related to the contact area between electrolyte and electrode material, which is determined by the microscopic morphology of the electrode material. Because of the large surface of nanoarray electrode for excellent electrochemical performances, CeO 2 /ZnO nanoarray electrodes were synthesized successfully for energy storage by the developed two kinds of different schemes in this paper. CeO 2 /ZnO nanorod array (C/Z NRA) and CeO 2 /ZnO nanosheet array (C/Z NSA) could be modulated by ZnO-rod sol–gel method and ZnO-seed hydrothermal method, respectively. The C/Z NRA owned a specific capacitance of 406.75 F g −1 and an energy density of 119.21 Wh kg −1 . However, the specific capacitance and energy density of C/Z NSA were 991.43 F g −1 and 222.82 Wh kg −1 , respectively. The electrochemical performances of C/Z NSA were about twice as large as the ones of C/Z NRA. The result is due to the fact that the castle-like C/Z NSA has a large number of voids to ensure its larger contact area with the electrolyte compared with cluster-like C/Z NRA. The difference of the performances of C/Z NRA and C/Z NSA is caused by the difference in their controlled microstructures. The structure–function relationship could be explained by from their SEM and XRD. The ultraviolet–visible (UV–Vis) analysis of C/Z NRA and C/Z NSA could be subjected to guiding effect on the subsequent photoelectric properties that will be relative to their electrochemical properties. The study implies that the idea has become a reality that nanostructure modulation of electrode material could be made to enhance its electrochemical properties for better energy storage according to one’s design and intention.