Porous ZnO/NiO Microspherical Structures Prepared by Thermolysis of Heterobimetallic Metal-Organic Framework as Supercapacitor Electrodes

In this work, porous ZnO/NiO microspherical structures have been devised and prepared successfully via a solid-state conversion process of heterobimetallic MOF. The results of structural characterization demonstrate that the products are porous ZnO/NiO microsphereical structures with the diameter of about 2 mu m, which are constructed by many interconnected nanocrystals with the sizes between 20 and 50 nm. The BET surface area of ZnO/NiO microspheres is calculated to be 170.01 m(2) g(-1) with a broad pore size around 7.5-25 nm. Electrochemical data illuminated that the specific capacitance of the porous ZnO/NiO micro-spheres is 172.9 F g(-1) at 0.5 A g(-1). Additionally, it shows better cycling performance that the specific capacitance is 143.7 F g(-1) for the first cycle at a current density of 1 A g(-1), and still retains 140.0 F g(-1) after 2000 cycles. Importantly, this simple calcination strategy could be easily extended to prepare other porous binary metal oxide nanomaterials with specific morphologies, high porosity and excellent electrochemical performance.