One-Pot Synthesis of ZnO Nanoparticles for Nitrite Sensing, Photocatalytic and Antibacterial Studies

In this work, we have carried out an eco-friendly route for synthesis of zinc oxide nanoparticles (ZnO NPs) via solution combustion method using Calotropis gigantea leaves extract as fuel and Zn(NO 3 ) 2 ·6H 2 O as an oxidizer. The NPs had been characterized employing various analytical techniques namely XRD, SEM, EDAX, HR-TEM with SAED, FT-IR and UV-DRS. XRD confirms crystalline nature with average crystallite size of 31 nm. SEM and HR-TEM images shows that particles are in hexagonal and pyramidal shapes with particles size of 10–50 nm. In FT-IR, characteristic vibrational mode of NPs was observed at 442 cm −1 . The Optical energy band gap was found to be 3.25 eV. Considering practical applications, ZnO NPs exhibited superior photocatalytic activity for degradation of Methylene blue dye. Antibacterial activity of ZnO NPs was screened against Staphylococcus aureus and Escherichia coli bacterial strains. Further, electrochemical performance of developed sensor using NPs was investigated employing electrochemical approaches for quantification of nitrite. Graphic Abstract