Green Synthesis of Nanostructure CeO₂ Using Tea Extract: Characterization and Adsorption of Dye from Aqueous Phase

Figure 4

XPS spectra of synthesized CeO₂ samples calcined at (a) 723 K, (b) 923 K, and (c) 1073 K (v and u indicate Ce 3d5/2 and Ce 3d3/2, respectively).