Synthesis and characterization of magnetically separable Zn1-xCoxFeMnO4 nanoferrites as highly efficient photocatalyst for degradation of dye under solar light irradiation

Abstract

Cobalt doped magnetically separable Zn1-xCoxFeMnO4 (x = 0.0, 0.25, 0.50, 0.75, 1.0) nanoparticles of ferrite were synthesized using auto-combustion process of sol-gel utilizing glycine as a fuel. The powder XRD and Rietveld refinement studies showed that all of the samples developed a single-phase cubic spinel system. The morphological investigations demonstrate the sphere-like nanostructures, which get distorted after an increase in the concentration of cobalt. A transformation from superparamagnetic activity to ferrimagnetic character has been reported with the introduction of Co2+. As synthesized ferrite nanoparticles have demonstrated an improvement in coercivity with lower density magnetization with reduced crystallite size. A rise in the remanence ratio were observed with the Co2+ content. The optical characterization shows a blue shift in the band gap with increase of Co2+. Considering the band structure in the visible region, the photocatalytic activity of as-synthesized Zn1-xCoxFeMnO4 photocatalysts for degradation of methylene blue under natural sunlight was investigated. The Zn0.25Co0.75MnFeO4 ferrite demonstrated more than 99% degradation of MB dye within 20 min. The effect of catalyst loading, pH, and stability of photocatalyst were studied.