Preparation of ZnCo2O4 porous nano-flower-like materials by one-step cryogenic hydrothermal method and study on their capacitive and photocatalytic properties

In this paper, the porous nano-flower structures were successfully constructed on carbon cloth (CC) substrate by a simple one-step cryogenic hydrothermal method. The morphology and phase analysis showed that the synthesized product was ZnCo2O4/CC with porous flower-like structure. The photocatalytic degradation experiment results show that the degradation rates of rhodamine B (RhB), methylene blue (MB), and Congo red (CR) were 98.2%, 96.8, and 98.5%, respectively. After 20 times of recycling, the cyclic stability still reached to 97.5%, 96.5%, and 97.1%, respectively. In the experiment, we also studied the electrochemical properties of porous ZnCo2O4/CC nano-flowers. When the current density was 2 A g−1, the specific capacity of the electrode was up to 1868 F g−1. And when the current density was 3 A g−1, the capacitance retention rate was up to 99.8% after 10,000 cycles. In the experiment, the prepared porous ZnCo2O4/CC nano-flower and activated carbon (AC) were assembled as asymmetric supercapacitor devices. The maximum window voltage of the asymmetric supercapacitor is 1.6 V, and the specific capacitance is preserved 98.1% after 10,000 cycles at the current density of 2 A g−1. The main reason is the synergistic effect between binary metal oxides and the three-dimensional porous structure.