Fabrication of electrochemically nonporous NiO–ZnO/TiO 2 nanotubes/Ti plates for photocatalytic disinfection of microbiological pollutants

Nonporous NiO–ZnO/TiO 2 nanotubes/Ti photocatalyst plates were fabricated via facile electrochemical method. The structural and morphological properties of the modified plates were investigated by scanning electron microscopy and X-ray diffraction, while their photoelectrochemical (PEC) characterizations were evaluated by transient photocurrent responses and electrochemical impedance spectroscopy. Antimicrobial activities of the fabricated plates against Escherichia coli bacteria and Candida albicans fungi were studied under UV light irradiation. The results indicated that the photocatalytic and PEC activities of the NiO–ZnO/TiO 2 nanotubes/Ti plates are much higher than those of TiO 2 nanotubes/Ti, ZnO/TiO 2 nanotubes/Ti and NiO/TiO 2 nanotubes/Ti. The synergetic effect among NiO, ZnO and TiO 2 nanotubes motivated a fast charge separation as well as a slow electron/hole recombination, thus increasing the photocatalytic performance of the nonporous NiO–ZnO/TiO 2 nanotubes/Ti photocatalyst plate.