Co3O4 Nanoparticles Modified TiO2 Nanotube Arrays with Improved Photoelectrochemical Performance

Co3O4 modified TiO2 nanotube arrays (TiO2-NTs) were successfully fabricated by electrodeposition and thermal oxidation process. The prepared samples were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopic (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance spectroscopy. The photoelectrocatalytic properties of as-prepared samples were investigated under visible light and UV-vis light irradiation. Meanwhile, taking methyl orange aqueous solution as target substrate for photoelectrocatalytic degradation experiments, the degradation rate under UV-vis light irradiation and dark condition were evaluated. The prepared Co3O4/TiO2-NTs exhibited much higher photoelectrochemical activity than TiO2-NTs under visible light irradiation and UV-vis light irradiation. The degradation rate of methyl orange on Co3O4/TiO2-NTs electrode reaches 90.7% under applied potential of 1.3 V and UV-vis light irradiation for 10 h, which is only 53.4% on TiO2-NTs electrode. The improved performance could be attributed to the higher photo-generated carrier concentration and carrier mobility.