Effect of cobalt substitution in Zn1-xCoxFeCrO4 ferri-chromate: emerging light absorber for degradation of model textile dye

Abstract

The concentration (x = 0.0 to 1.0) of cobalt doped magnetically separable Zn1-xCoxFeCrO4 ferrite was produced by sol-gel auto combustion utilizing glycine as a fuel. We can deduce that a single-phase cubic spinel system is synthesized based on powder XRD measurements and Rietveld refinement of the Zn1-xCoxFeCrO4 ferrite system. With the increase in cobalt content in the Zn1-xCoxFeCrO4 ferrite system, morphological examination revealed irregularly formed nanostructures ranging in size from 10 nm to 40 nm. When this ferrite system was exposed to TEM examination, similar morphological results were found. The coercivity of the Zn1-xCoxFeCrO4 ferrite system increased as the density and crystallite size were reduced. The remanence ratio rises in proportion to the increase in cobalt content. The visible region's optical characteristics were studied, and a blue shift in the band gap was observed with the increase in concentration of cobalt. The photo catalytic activity of as-synthesized Zn1-xCoxFeCrO4 ferrites on methylene blue (MB) dye degradation was evaluated because the band gap of the catalysts lies in the visible region. Within 85 minutes, the targeted photocatalyst degraded 96.7% of methylene blue, equating to a high degradation reaction rate constant k value up to 0.0089 min−1. As a result, the catalyst has a bright future in terms of environmental remediation. Increased photo catalytic activity is attributed to inhibition of load carrier separation due to crystallinity, proper band energy structure, and morphology of Co2+ doped Zn1-xCoxFeCrO4 ferrite. In addition, our targeted photo catalyst Zn0.25Co0.75FeCrO4 showed good stability and radical scavenger tests suggesting that holes/ hydroxyl radicals were the primary components for increased activity.