Phyto-synthesis of Pure and Mn Doped SnO2 Nanoparticles: Evaluation of Antimicrobial, Antioxidant and Photocatalytic Activities

In the present work, a series of Sn1-xMnxO2 (x = 0.00, 0.03, 0.05 and 0.07) nanoparticles were fabricated by eco-friendly, green method using Annona muricata leaf extract as capping and reducing agent. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoemission spectroscopy (XPS), high resolution transmission electron microscope (HRTEM), selected area diffraction pattern (SAED), UV-Visible spectroscopy (UV-Vis), scanning electron microscope (SEM) and energy dispersive x-ray (EDX) spectra. All the XRD pattern reveals manganese (Mn) ions are successfully incorporated into tin oxide (SnO2) crystal lattice with tetragonal rutile structure. The band around 445 cm(-1) in FTIR spectra corresponds to Sn-O stretching vibration. XPS results indicates Mn2+ ions are effectively substituted by Sn4+ ions. HR-TEM and SEM micrograph shows spherical shape SnO2 nanoparticles. EDX spectrum confirms the presence of Sn, Mn and O elements, indicate the purity of synthesized sample. The decrease in optical bandgap energy with increase in dopant concentration is observed from UV-Visible absorption spectra. The antimicrobial activity of pure and Mn doped SnO2 nanoparticles was studied against P. aeruginosa, S. aureus, C.albicans and A.niger microbial strains. Moreover, the antioxidant activity was measured by DPPH assay. Besides that, the photocatalytic activity of SnO2 and Sn0.93Mn0.07O2 nanoparticles was tested against methylene blue (MB) dye under direct solar irradiation shows about 89 and 91% of dye got degraded after 120 min. Therefore, our report demonstrates that the plant extract mediated synthesised pure and Mn doped SnO2 nanoparticles is a promising material used in health care and environmental applications.