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.