Supersonically sprayed copper oxide titania nanowires for antibacterial activities and water purification

Copper and TiO₂ particles are supersonically sprayed to produce nanowire surfaces for bacterial disinfection and water purification. Supersonically sprayed copper oxide (CuO) and titania (TiO₂) are transformed into nanowires after annealing. The presence of these nanowires facilitates efficient interfacial antibacterial activities. A pure CuO film (without TiO₂) does not become photoactive under ultraviolet (UV) irradiation; nevertheless, it can inhibit Escherichia coli (E. Coli) by up to 70.8%. The inhibition rate of E. coli on a CuO/TiO₂ composite under UV irradiation is 100%, which demonstrates the excellent photo-killing activity of TiO₂. Thus, the CuO/TiO₂ composite is superior to the pure CuO film in terms of its photo-killing capability. However, the use of a pure CuO film is preferred to that of a TiO₂ film when UV irradiation is not available. The water contact angle of the CuO/TiO₂ composite confirms its superhydrophilicity, which can attract bacteria-containing aerosols in the air, thereby reducing air contamination. The textured surfaces of these films are characterized using scanning electron microscopy, three-dimensional optical profilometry, X-ray photoelectron spectroscopy, and transmission electron microscopy.