Potential of Piper betle@Co3O4 nanoparticles as high-performance photocatalysts for the removal of industrial dyes

Abstract

In this study, cobalt oxide (Co3O4) NPs were bio-synthesized for photocatalytic application through the reduction of cobalt chloride hexahydrate using extract of Piper betle (e.g., polyphenols). The as-prepared Co3O4 NPs exhibited the face-centered cubic structure of Co3O4 with the crystallite sizes ranging from 20 to 30 nm with an energy band gap of 3.86 eV. FTIR spectra revealed that Piper betle extracts were present on the surface of the resulting Co3O4. HRTEM confirmed the dispersion of non-agglomerated uniformly spherical particles over a large area. The photocatalytic activity of the Co3O4 NPs was investigated for the degradation of the industrial dye, Eriochrome Black T (EBT). The degradation efficiency of EBT could exceed 94% within 80 min under UV light. The Piper betle@Co3O4 NPs recorded superior performance (quantum yield of 1.98 × 10−4 Φ and figure-of-merit of 1.59 × 10−9 mol L J−1 g−1 h−1) with a low energy requirement of 2.35 × 109 J mol−1. As such, the Piper betle@Co3O4 NPs are recognized as a high-efficiency photocatalyst for efficient degradation of industrial dyes.