Solid-state preparation of CuO/ZnO nanocomposites for functional supercapacitor electrodes and photocatalysts with enhanced photocatalytic properties

In this paper, hybrid CuO/ZnO nanocomposites are synthesized by a simple and cost-effective solid-state grinding method for multifunctional applications as supercapacitor electrodes and photocatalysts for the degradation of dye pollutants. In the synthesis process, ZnCO3-SLS used as a reactant that not only provides Zn source but also serves as a template to induce the nanoparticles to arrange orderly. The resultant CuO/ZnO (ZnCO3-SLS, 1.00 g) nanocomposites exhibit a maximum degradation efficiency of 91.5% for Rhodamine B and 74.3% for Congo Red under visible light irradiation for 240 min, respectively. Besides, it also demonstrates high specific capacitance of 579.5 F g−1 and excellent cyclic performance with nearly 83.0% capacity retention after 2000 cycles at a current density of 5 A g−1, seemed to be superior to other nanocomposites. The excellent electrochemical performance can be attributed to a rational combination of two electrochemical active materials. The hybrid nanocomposites design opens up new opportunities to use in wastewater treatment and energy storage applications.