Facile fabrication of Au@CoFe₂O₄-ZnO hybrid plasmonic nanostructures with enhanced photocatalytic performance

Multicomponent hybrid nanostructures exhibit multifunctional properties and synergistic performance which make them attractive materials for environmental applications. We have fabricated magnetic Au@CoFe₂O₄-ZnO hybrid plasmonic nanostructures using simple wet chemical route combined with photodeposition and studied their photocatalytic performance towards decomposition of synthetic dyes. XRD, FESEM and Raman were used to examine the structure and morphology of the prepared nanostructures and UV–visible spectroscopy was used for photocatalytic measurements. The solar-responsive photocatalytic decomposition of synthetic dyes MB and MO was examined and results displayed the outstanding performance of Au loaded CoFe₂O₄-ZnO nanostructures over CoFe₂O₄-ZnO photocatalysts. The prepared Au@CoFe₂O₄-ZnO hybrid nanostructures with higher Au loading, the sample CU3, effectively decolorized MB dye in only 20 min of sunlight exposure, achieving an apparent rate constant of 0.062 min⁻¹. For MO dye, the sample CU3 achieved 96.6% degradation in 60 min with an apparent rate constant of 0.022 min⁻¹. Mechanistic studies related to radicals responsible for the photodecomposition were discussed and results revealed that ⋅OH radicals and hot holes play major roles in photodecomposition of pollutants. Overall, Au decorated CoFe₂O₄-ZnO nanostructures prepared using facile photodecomposition route with excellent recyclability and effortless magnetic recovery represent a promising photocatalyst material and is highly suitable photocatalyst for environmental remediation applications.