This paper deals with the degradation effect of undoped and doped ZnO as photocatalysts on methyl orange (MO). The undoped and doped ZnO photocatalysts were synthesized by wet chemical method. The photocatalytic study of the synthesized samples was carried out under UV light in the short wavelength range of 254 nm with UV- absorption analysis. It was observed from the UV absorption analysis that undoped ZnO has pronounced effect in the degradation of MO in comparison with Ti⁴⁺, Cu²⁺, Mn²⁺ ion doped ZnO. This result suggests that, the larger band gap of undoped ZnO (3.37 eV for bulk ZnO), would have promoted the photocatalysis upon UV illumination with MO. In addition to this, surface defects would have played a role in the degradation of MO in this metal oxide semiconductor. The vibrating sample magnetometer study of transition metal ion doped ZnO exhibited ferromagnetic interaction at room temperature. It was also observed from the present study that the wet chemical method of synthesis of ZnO and ZnO based compounds has the advantage of producing nano sized crystallized powder of high purity at low temperature. Theoretical investigation on the properties of undoped and doped ZnO has also been carried out. From theoretical calculations, it is observed that undoped Zn₆O₆ cluster is kinetically stable when compared with transition metal ion doped Zn₆O₆ cluster.

Keywords: Photocatalytic Study; Methyl Orange; Surface Defects; Ferromagnetic Interaction;