One-pot synthesis of ZnS nanowires/Cu ₇S ₄ nanoparticles/reduced graphene oxide nanocomposites for supercapacitor and photocatalysis applications

Abstract

ZnS nanowires/Cu ₇S ₄ nanoparticles/rGO nanocomposites were fabricated as photocatalysts and supercapacitor electrodes for the first time.

Abstract

The zinc sulfide (ZnS) nanowires (NWs)/analite (Cu ₇S ₄) 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/Cu ₇S ₄ 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/Cu ₇S ₄ 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/Cu ₇S ₄ 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, Cu ₇S ₄ NPs and rGO.