Cd2V2O7–ZnO mixed oxide for extended wavelength absorption with suppressed charge carrier recombination: A photocatalytic material

Abstract

A type-II mixed oxide Cd2V2O7–ZnO was prepared by hydrothermal method and its morphological and optical properties were analysed with various scientific techniques. FESEM and AFM images showed the aggregated porous morphology by the individual spherical particles. The X-ray diffraction studies confirmed its formation, crystallinity and size of the particles as 47 nm. The UV–visible DRS spectrum showed its visible light-responsive nature and the optical band gap of bare ZnO and Cd2V2O7–ZnO mixed oxide to be 3.3 and 3.0 eV respectively. The mixed oxide also revealed the extended lifetime of the charge carriers by means of decreased excitonic emission intensity from the conduction band to valence band. The prepared mixed oxide was employed as photocatalyst in the degradation of methylene blue dye under solar radiation, the results indicated that the mixed oxide degraded the dye to an extent of 90% in just 30 min of light reaction in comparison to bare ZnO which degraded the dye to an extent of 69% in the same period. The degradation reaction followed pseudo-first-order reaction kinetics with the rate constant of 4.097 × 10−2 min−1 for ZnO and 6.665 × 10−2 min−1 for Cd2V2O7–ZnO mixed oxide composite.