Zinc oxide nanoparticles (nZnO) were synthesized by simple sol-gel auto combustion method using zinc nitrate as an oxidizer and different fuels such as urea, glycine and urea+glycine mixture. The products were characterized by means of XRD, FT-IR, UV-Vis, and HR-TEM spectroscopy. The average crystallite size of nZnO was found to be 46.0, 33.4 and 41.1 nm, for the aforementioned fuels, respectively. The band gap energy value of nZnO was found to be in the range of 3.25-3.72 eV. Plus, the methylene blue dye was photocatalytically degraded in presence of nZnO photocatalyst by ≥ 98% within 4.0 h with a rate constant≈0.002 min-1. The as-prepared nZnO showed excellent antibacterial properties.