Intimate coupling of 3D MnFe2O4 cubes on 1D ZnO nanorods for sustainable photocatalysis under visible light: Computational analysis of reactive sites and degradation pathway.

• Facile synthesis of ZnO/MnFe 2 O 4 photocatalyst was achieved by the sonochemical method. • Efficient photocatalytic mineralization of Methylene blue dye was achieved. • ZnO/MnFe 2 O 4 showed excellent stability and reusability. • OH- radicals are the primary reactive species involved in the degradation of methylene blue. • Photocatalytic mechanism of ZnO/MnFe 2 O 4 and the degradation pathway were proposed. In recent times, the discharge of wastewater containing aromatic compounds has serious effects on human health and the environment. Thus the fabrication of an efficient and visible light-active nano photocatalyst offers an optimum and sustainable solution. In this study, ZnO/MnFe 2 O 4 nanocatalyst was fabricated by the ultrasonication mediated reflux method. The fabricated nanomaterials were characterized with SEM, TEM, XRD, XPS, UV-visible DRS, BET, EIS, PL, ESR analysis. The ensued nanocomposite (NCs) was employed for the photocatalytic removal of methylene blue (MB) dye. The photocatalytic efficiency of ZnO/MnFe 2 O 4 NCs for the removal of MB was 85% which was higher than the efficiency of both the individual semiconductors ZnO (63%) and MnFe 2 O 4 (69%). The rate constant for the photocatalytic removal of MB by ZnO/MnFe 2 O 4 NCs (0.07 min⁻¹) was 12 times higher than the ZnO (0.006 min⁻¹) and 1.75 times higher than MnFe 2 O 4 (0.04 min⁻¹). The boosted photocatalytic performance of ZnO/MnFe 2 O 4 was attributed to the higher surface area (204.559 m²/g) with more active sites compared to ZnO (188.212 m²/g) and MnFe 2 O 4 (106.893 m²/g). The as-fabricated ZnO/MnFe 2 O 4 NCs possess excellent stability as affirmed by recycle test and the analysis of reused XRD. The major part of the degradation of MB was performed by •OH⁻ radicals which was confirmed by scavenging test. The overall results suggest that the fabricated ZnO/MnFe 2 O 4 is an active material for photocatalytic applications. [Display omitted] [ABSTRACT FROM AUTHOR]