In this work, mesoporous MCM-41 nanoparticles (MCM-41NPs) were synthesized using the rice husk ash (RHA), as the silica source at room temperature. Ag2O quantum dots were prepared using a chemical method in matrix nanoparticles, and used as an antibacterial material. Bactericidal activity of the nanomaterials was investigated against E. coli and S. aureus bacteria. The synthesized materials were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscope (TEM). The minimum concentrations of nanocomposite to inhibit the growth of E. coli and S. aureus strains were 12.5 µg/mL. The Ag2O quantum dots indicated acceptable antimicrobial properties, with an average diameter of 16 mm.