Zirconium dioxide nanomaterials doped with samarium were produced through a bio-template method, utilizing citric acid as a fuel. Various advanced methods, for instance, XRD, TEM, EDX, PL, XPS, and UV–Vis spectrophotometry, were employed to characterize the compositions. XRD analysis confirmed that all peaks corresponded to the tetragonal phase of ZrO2, with no presence of impurities from other phases. The elemental composition was analyzed using EDX, verifying the presence of Zr, Sm, and O. The energy gap widening concerning the pure ZrO2 may be the well-known Moss–Burstein shift. This shift was linked to an increase in the bandgap (from 5.25eV to 5.54eV) with increasing concentrations of Sm. This observation was made during the analysis of the photocatalysis of pure ZrO2 and various concentrations of Sm-doped ZrO2 for Methylene Blue. The augmentation of Sm doping resulted in an improvement in the efficiency of removing Methylene Blue, increasing the removal rate from 35% to 80%.
