Green-synthesized flattened rice-shaped CuO and metal doped CuO nanoparticles using Bauhinia racemosa Lam. leaves extract and their photocatalytic and biological applications

Abstract

In the present investigation, a sustainable approach to the biogenic fabrication of CuO nanoparticles (NPs) and transition metals (Co, Mn, and Zn) doped CuO NPs (TMDC NPs) was proposed by employing the Bauhinia racemosa (BR) Lam. leaves extract as a stabilizing and capping agent. The fabrication of CuONPs was immediately verified by a change in the color of the Cu solution from blue to dark grey. Characterizations of the bare CuO and TMDC NPs were done to attribute the physical and chemical characteristics of the NPs employing Fourier Transform Infrared (FT-IR), X-ray Diffraction (XRD), UV–Vis Diffuse Reflectance Spectroscopy (UV–Vis DRS), Photoluminescence (PL), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX), Transmission Electron Microscopy (TEM), and Brunauer − Emmet − Teller (BET) studies. The acquired Co-CuO NPs demonstrated a substantial crystallinity, smaller crystallite size of ∼10.87 nm, lower bandgap, and reduced recombination rate and were implemented as an effective photocatalyst for the degradation of the amoxicillin (AMX) and tetracycline (TC) antibiotics, as examined by UV − vis spectrophotometric study and confirmed by a hypochromic shift. Based on UV − vis analysis, Co-CuO NPs demonstrated a potent and rapid photocatalytic degradation performance of ∼99 and ∼93 % for the AMX and TC antibiotics within 150 and 210 min respectively. Co-CuO NPs also demonstrated strong antimicrobial performance against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Aspergillusflavus, Aspergillusniger, and Bacillus subtilis. Further investigation of in-vitro cytotoxic potential against the A549 cell line, utilizing MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay and the free radical scavenging performance of the Co-CuO NPs was estimated by DPPH (2,2-diphenyl-1-picrylhydrazyl) assay utilizing L-ascorbic acid as reference were also performed.