Drastic photocatalytic degradation of methylene blue dye by neodymium doped zirconium oxide as photocatalyst under visible light irradiation

Abstract Nanocrystalline ZrO 2 and neodymium doped ZrO 2 (Nd–ZrO 2 ) were successfully prepared by a polymer- assisted, sol-gel method and characterized by XRD, SEM, HRTEM, XPS and UV–vis techniques. X-Ray diffraction studies revealed the formation of highly crystalline structures of ZrO 2 and (Nd–ZrO 2 ) samples. SEM images proved the evenly distributed nano - structured, spherically - shaped ZrO 2 particles of size 40 nm, which was reduced to 20 nm, when doped with neodymium. Light absorption properties of the nanoparticles were studied by UV–vis spectrophotometer. Nd - doped ZrO 2 was having a band gap of 2.8 ev, while that of ZrO 2 , was 2.6 ev. Thus, Nd substituted ZrO 2 effected substantial shifting of the absorption edge of zirconium oxide to red and resulting in the enhancement of visible light absorption The increase in band gap of Nd–ZrO 2 was resulted in an increasing light absorbtion tendency of Nd − ZrO 2 , which promoted the photocatalytic efficiency of it. XPS results confirmed substitution of Nd in ZrO 2 . Photocatalytic results for the degradation of methylene blue had indicated the fact that neodymium substitution dramatically enhanced the catalytic activity of zirconium oxide. This means that the neodymium − substituted zirconium oxide has the highest photocatalytic activity under visible light irradiation.