One-pot synthesis of ZnS nanowires/Cu7S4 nanoparticles/reduced graphene oxide nanocomposites for supercapacitor and photocatalysis applications

Abstract

The zinc sulfide (ZnS) nanowires (NWs)/analite (Cu₇S₄) nanoparticles (NPs)/reduced graphene oxide (rGO) nanocomposites were fabricated for the first time using a one-pot hydrothermal method, and the resulting nanocomposites can be used as a photocatalyst and the electrode for a supercapacitor. The ZnS NWs/Cu₇S₄ NPs/rGO nanocomposites showed excellent electrochemical performance with the maximum specific capacitance of 1114 F g⁻¹ at a current density of 1 A g⁻¹, good cycling stability with capacitance retention of 88% after 5000 cycles and low charge transfer resistance of 0.011 Ω. The ZnS NWs/Cu₇S₄ NPs/rGO nanocomposites were used as the positive electrode together with active carbon as the negative electrode for the fabrication of an asymmetric supercapacitor device, which exhibited a maximum energy density of 22 W h kg⁻¹ as well as a power density up to 595 W kg⁻¹ with capacitance retention of 77% after 5000 cycles. Furthermore, ZnS NWs/Cu₇S₄ NPs/rGO nanocomposites exhibited superior photocatalytic activity under ultraviolet and visible light irradiation because of the high surface area, small interface transfer resistance and efficient separation of photogenerated electrons and holes caused by the synergistic effect between ZnS NWs, Cu₇S₄ NPs and rGO.