A novel synthesis protocol for Co3O4 nanocatalysts and their catalytic applications

Abstract

Co₃O₄ spinel nanoparticles (Co₃O₄-NPs) are synthesized via a green route using neem (Azadirachta indica) leaf by an efficient and simple hot plate combustion method (HPCM). The as-prepared Co₃O₄-NPs have been characterized by well-known recognized techniques such as X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), Raman spectroscopy, and vibrating sample magnetometry (VSM). Co₃O₄-NPs were investigated in various application areas; for example, a multi-lamp photocatalytic reactor was used to degrade the hazardous textile dye waste (TDW) collected from the dyeing industry. Furthermore, the antimicrobial activity of the synthesized Co₃O₄-NPs was studied against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria, in comparison to a chloramphenicol standard, and also evaluated by carrying out the catalytic hydrogenation of 4-nitrophenol and 4-nitroaniline in the presence of NaBH₄ as a reducing agent. Noble metals have been reported earlier, but due to their high cost they needed to be replaced by a cost effective material. We have also discussed feasible mechanisms and catalytic activity of the Co₃O₄-NPs in different applications. Thus, we have proposed a novel, economic and green synthesis of Co₃O₄-NPs that is highly important in the present times for the removal of hazardous chemicals.