Photocatalytic performance of Co-MOF-derived Co 3 O 4 nanoparticles for degradation of herbal cigarette detritus and industrial dyes in wastewater

In the present work, Co₃O₄ nanoparticles (Co₃O₄ NPs) were prepared by calcination of a hydrothermally synthesized Co-MOF precursor. The X-ray diffraction (XRD) analysis results confirmed the formation of Co₃O₄ NPs with well-defined cubic spinel oxide (Fd-3m phase) with an average crystallite size of ∼22 nm, while Fourier transform-infrared (FTIR) spectra supported the presence of Co-O bonding through prominent vibrational modes at 562 and 663 cm^-1. The SEM images demonstrated that the Co₃O₄ NPs possess porous flower-like morphology, and EDAX confirmed the existence of cobalt and oxygen atoms. The PL analysis reveals prominent defect-related emissions in Co₃O₄ nanoparticles, confirming abundant defect states that can enhance their photocatalytic activity. The vibrating sample magnetometry (VSM) analysis demonstrated antiferromagnetic behavior, which was consistent with nanoscale Co₃O₄ NPs. The prepared Co₃O₄ NPs displayed superior photocatalytic activity toward the degradation of emerging wastewater pollutants. The experimental results demonstrated that about 96% degradation of herbal cigarette detritus in 160 min, and almost complete degradation of industrial dyes, namely Janus Green B, Methyl Violet 2B, and Congo Red in 30, 60, and 40 min, respectively, under UV-light irradiation.