Peanut shell biotemplate to fabricate porous magnetic Co3O4 coral reef and its catalytic properties for p-nitrophenol reduction and oxidative dye degradation

Abstract

The biotemplate assisted synthesis route is environmentally friendly, cost effective and easy. It employs a biomaterial like fruit waste, vegetable waste, bio-macromolecule, etc. for attaining a specific morphology of the as-synthesized product. Herein, we report the novel synthesis of magnetic, coral-reef like spinel-Co3O4 nanoparticles (m-Co3O4 NPs) by the immersion-calcination technique using peanut peel as a biotemplate. The as-synthesized material has been characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), Brunauer–Emmett–Teller (BET) and X-ray photoelectron spectroscopy (XPS) analyses, which revealed the magnetic nature and spinel structure of coral-reef-like m-Co3O4 NPs possessing a high surface area (103 m2/g). The synthesized m-Co3O4 NPs have been successfully used as nanocatalysts for the reduction of para-nitrophenol to para-aminophenol in the presence of NaBH4, as well as for the advanced oxidative degradation of the Orange G dye by using the environmentally benign oxone. The pseudo first order kinetics model was followed by both the reactions. The as-prepared nanocatalyst demonstrated high stability and easy recovery by an external magnet for successive use without any substantial loss in activity up to five consecutive cycles for both the reactions. Hence, m-Co3O4 NPs are potential candidates as catalysts in reduction as well as oxidation reactions, specially to obtain valuable products like amines that possess high industrial value and for the removal of toxic water pollutants like organic dyes.