Facile chemical synthesis of mixed Zn-Co manganite based tetragonal spinels for energy storage and environmental remediation

In this study, the mixed Zn-Co manganite based spinels Zn1−xCoxMn2O4 (where x = 0, 0.05, 0.10, 0.15, 0.20, and 0.25) were prepared by the chemical co-precipitation route. The fabricated Co-doped ZnMn2O4 spinels were characterized by XRD, SEM, FT-IR, EDAX, BET, TEM, and UV–vis spectroscopy techniques. The XRD studies detailed the crystal-structure of body-centered tetragonal zinc manganite spinels. EDAX analysis showed the existence of pure phase elements, and the atomic-weight percentages of elements closely match with those present in the respective precursors. The BET surface areas of ZM P and ZCM 5 samples were found to be 22.52 and 36.76 m2/g, respectively. The metal-oxygen bonds of the zinc manganite spinel materials were appeared at 518 and 638 cm−1. The interplanar distance of 0.28 and 0.46 nm, assigned to the (200) and (112) crystal planes of ZnMn2O4, respectively. The band gap energies of the samples decreased from 3.3 to 3.22 eV with increased dopant concentration. The photodegradation efficiency of prepared samples was evaluated by Rhodamine 6G dye under UV illumination. The electrochemical properties were examined by CV, GCD, and EIS. The experimental observations exhibited that the fabricated Co-doped ZnMn2O4 sample (ZCM 5) showed greater photocatalytic activity (87 % after 120 min) and outstanding electrochemical performance (486 F g−1) than undoped ZnMn2O4 (ZM P) material. ZCM 5 electrode material demonstrated excellent cycling life, with 88 % capacitance retention after performing for 1000 cycles.