Synthesis, Characterization, and Antibacterial Studies of Nickel–Silica Nanoparticles

In this study, nickel–silica nanoparticles SiO₂@Ni(II) and SiO₂@Ni(0) were prepared from rice husk using the sol-gel method. Nickel–silica nanoparticles were identified using several appropriate physical techniques. According to XRD, the nickel–silica nanoparticles exist in the amorphous phase and weak crystalline phase. N₂- adsorption and desorption analysis showed that the nickel–silica nanoparticles have isotherm type IV and exhibit an H3 hysteresis loop. Analysis of scanning electron microscope (SEM) images revealed that the nickel–silica nanoparticles SiO₂@Ni(II) and SiO₂@Ni(0) have sizes approximately 50–150 nm. Diffuse reflectance absorption ultraviolet (DRUV–vis) spectra of nickel–silica nanoparticles showed a number of electronic transitions due to charge transfers and d-d transitions in the octahedral field around Ni(II). The antibacterial activity of SiO₂@Ni (II) and SiO₂@Ni(0) was investigated with E. coli and S. aureus. These nanoparticles showed clear inhibition at high concentrations, especially with S. aureus bacteria. This effect was also observed by studying the MIC against the studied bacteria.