The quantity of Zn-N components decreased after the adsorption of FLU dye. Such decrease might be attributed to the leaching of Zn, as will be discussed later. In O1s spectra (Figure DRS spectra of ZIF-8 and ZnO@N-doped C were recorded (Figure ). ZnO and ZIF-8 exhibit absorbance below 400 nm. On the other hand, ZnO@N-doped C shows continuous absorbance in the 200-1000 nm (Figure ). The bandgaps for ZIF-8 and ZnO have been estimated via the Tauc plot (Figure ), and these bandgaps are 4.34 eV and 3.12 eV, respectively. The UV-Vis diffuse DRS analysis using the Tauc plot showed that the N-doped ZnO has a bandgap of 2.07 eV (Figure ). The low bandgap of ZnO@N-doped C compared to both ZnO and ZIF-8 explains its high catalytic performance compared to the other materials.