Solar light driven transition metal codoped ZnO (Ag, Ni- codoped ZnO) photocatalyst for environmental remediation

Abstract

Visible light efficient Ag, Ni-codoped ZnO photocatalyst has been synthesised in the nano form by co-precipitation and sonochemical method using ZnSO4ꞏ7H2O as a precursor. The structural, morphological and elemental observations of synthesised photocatalyst have been characterized using X-ray diffraction (XRD), FTIR, UV-DRS, SEM with EDX and HRTEM analysis. Incorporation of metal ions into ZnO lattice caused a red shift in the absorption band thus extending its absorption towards visible region through inhibition of electron hole recombination reaction and through the property of surface plasmon resonance (SPR). However the addition of silver and nickel ions has modified the electronic and optical properties of the photocatalyst thus improving the photocatalytic performance of the sample. The photocatalytic performance of Ag, Ni-codoped ZnO nanoparticles have been tested for degradation of Direct Red 81 dye (DR-81), as pollutant in aqueous solution. Under the optimum conditions (20 ppm dye and 10 mg/L photocatalyst), complete mineralization of dye solution under study was achieved within 40min of time duration. The Ag, Ni-codoped ZnO photocatalyst is thermally stable and efficient for five successive consecutive runs thus retaining its efficiency towards degradation. The overall results thus obtained have suggested that a suitable method for the detoxification of environmental pollutants emerging from industries.