The ZAO NPs with homogeneous dispersion and stable crystal
structure were synthesized through synergistic reaction between
ultrasonic-microwave and dispersants, and the nanoparticle size
could be controlled through choosing dispersants. As the decrease
in particle size of ZAO NPs, the bandgap broaded and higherenergy
UV rays are absorbed. Interestingly, this can speed up the
generation of highly reactive species, and enhances the sterilization
effect. When the particle size of ZAO NPs reaches 20 nm,
the ZAO NPs has most effective sterilization activity. The cost of