Green-synthesized CuO and Cu₂O nanoparticles using Heliotropium indicum leaf extract were characterized by XRD, TEM, and SEM. TC photodegradation and antibacterial activities against S. aureus were evaluated.

Abstract

Green-synthesized copper oxide nanoparticles (both CuO NPs and Cu₂O NPs) have drawn increasing attention due to their distinctive properties and diverse applications. This study aims to synthesize CuO NPs and Cu₂O NPs using leaf extracts from the traditional medicinal plant Heliotropium indicum (H.I) and assessing their photocatalytic and antibacterial performance. X-ray diffraction (XRD) analysis confirmed monoclinic CuO and cubic Cu₂O structures with crystallite sizes of 20 nm and 17 nm, respectively. SEM and TEM analysis showed that the synthesized HI@Cu₂O NPs exhibited a near-spherical morphology with an average size of ∼10 nm, while HI@CuO NPs displayed a self-assembled spherical-like structure with an average size of ∼230 nm. The FTIR analysis reveals distinct functional groups in the nanoparticles, compared to the plant extract. The degradation efficiency of tetracycline (TC) reaches 82% and 78% within 60 min for HI@Cu₂O NPs and HI@CuO NPs, respectively. Turnover number (TON) and turnover frequency (TOF) were determined for the visible light-driven photocatalytic degradation of TC. Results showed that HI@Cu₂O NPs exhibited superior antibacterial performance against Staphylococcus aureus compared to HI@CuO NPs. Thus, a facile sustainable synthesis of CuO NPs using H. indicum leaf extract highlights their potential for application in photocatalytic wastewater treatment and biomedical fields.