Nanoarchitectonics of ZnCr2O4 nanoparticles and studies on their morphology-dependent magnetic and photocatalytic properties for sustainable removal of Amido Black 10B

Transition metal chromite nanoparticles are promising multi-functional materials owing to their tunable physicochemical properties, making them useful in energy and environmental fields. Herein, we report a facile synthetic approach for ZnCr₂O₄ nanoparticles (NPs) via a thermal decomposition route. The nanoarchitecture of the synthesized ZnCr₂O₄ nanoparticles could be tuned by varying the chemical nature of solvent, the volume of solvent, and using a mixture of solvents. The ZnCr₂O₄ NPs, synthesized under different conditions, were characterized using various techniques such as PXRD, FT-IR spectroscopy, TGA, Raman spectroscopy, UV-visible spectroscopy, PL spectroscopy, FE-SEM, HR-TEM, BET, SQUID, and XPS. P-XRD analysis confirmed the formation of pure ZnCr₂O₄ nanoparticles. Electron microscopy analysis revealed the formation of raspberry, porous, hexagonal, and agglomerated ZnCr₂O₄ nanoparticles under different synthetic conditions. The presence of Zn²⁺, Cr³⁺, Cr²⁺, and O²⁻ in the ZnCr₂O₄ nanoparticles was confirmed through XPS studies. BET analysis indicated a high surface area (39.9 m² g⁻¹ to 109.5 m² g⁻¹) of ZnCr₂O₄ nanoparticles. At 300 K, the ZnCr₂O₄ nanoparticles exhibited paramagnetic behaviour, while at 5 K they showed antiferromagnetic behaviour. The ZnCr₂O₄ nanoparticles were tested for their potential application as a photocatalyst for the removal of Amido Black 10B (AB 10B, a toxic dye) from an aqueous solution. They exhibited a photocatalytic degradation efficiency of 94% in 60 min and the catalytic activity was morphology dependent.