Visible light driven photocatalytic and competent antioxidant properties of phyto-fabricated zinc oxide nanoparticles (ZnO-NPs) from Borreria hispida

Abstract

Zinc oxide nanoparticles (ZnO-NPs) have gained considerable interest in biological and photocatalytic applications due to their distinctive physico-chemical characteristics. The study aimed to synthesize ZnO-NPs using the leaf extract of Borreria hispida, a medicinally important plant for its antioxidant and photocatalytic efficacy. The B. hispida mediated ZnO-NPs (Bh-ZnO-NPs) illustrated a characteristic peak at 304 nm with 3.45 eV bandgap energy during the spectral analysis. The Bh-ZnO-NPs XRD studies revealed stiff and narrow peaks with ∼21.87 nm in size. The SEM analysis revealed that the obtained Bh-ZnO-NPs were agglomerated and ZnO elemental purity of 98.23% was confirmed through EDS. The spectral results of Bh-ZnO-NPs obtained by the FT-IR affirmed that phyto-constituents participated in the reduction, capping and stabilization of the particles during the synthesis of nanoparticles. The BET surface area analysis of the Bh-ZnO-NPs confirmed that the particles exhibit a similar Type – IV isotherm curve as per IUPAC classification with 11.681 m2g-1 and a surface roughness (Ra) value of 6.25 nm. The Bh-ZnO-NPs offered significant (p ≤ 0.05) radical scavenging activity, which was dose-dependent with IC50 value falling between 0.6 to 0.8 mg mL−1 among the evaluated test methods. Methyl red (MR) dye degradation tests employing phyto-fabricated Bh-ZnO-NPs resulted in dye degradation up to 94.22% after 40 min of solar irradiation and the decolorization of MR dye followed pseudo-first-order kinetics. In addition to those mentioned above, the fifth cycle of the photocatalyst's stability and reusability studies showed 84.8% dye degradation ability. The findings demonstrate that the phyto-fabricated ZnO-NPs from B. hispida have potent antioxidant and dye-degrading properties that can be investigated at an industrial scale.