文摘
Morphologically different Bi2WO6 nanostructures have been synthesized via a hydrothermal route, where the morphology was tailored by varying the pH value of the precursor solution. The samples prepared at pH 1, 7, and 11 consisted of flower-like hierarchical structures with average diameter of 7 μm, irregular flake-like structures with average thickness of 90 nm, and uniform spherical structures with average size of 85 nm, respectively. The electrochemical performance of the as-prepared Bi2WO6 samples was investigated by cyclic voltammetry, galvanostatic charge–discharge measurements, and electrochemical impedance spectroscopy. In 1 M KOH electrolyte at current density of 0.5 mA cm−2, the specific capacitance of the Bi2WO6 with flower-like hierarchical, flake-like, and spherical structure was measured to be 255 F g−1, 214 F g−1, and 412 F g−1, respectively. After 850 charge–discharge cycles at current density of 3 mA cm−2, the capacitance of the three samples remained at 87%, 78%, and 95% of the initial value, respectively. Among the three types of Bi2WO6 morphology, the spherical structure delivered the best electrochemical performance.