Facile synthesis of CuxO (x = 1, 2)/TiO2 nanotube arrays as an efficient visible-light driven photocatalysts

Abstract

TiO2 nanotube arrays (TNTs) modified with CuxO (x = 1, 2) were prepared by a simple impregnation-calcinations method. The obtained samples were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy , UV–Vis diffuse reflectance spectroscopy and photocurrent tests. The photocatalytic ability of the as-prepared photocatalysts was evaluated using rhodamine B (RhB) as a target pollutant. Compared with pure TNTs, the CuxO/TNTs composite exhibited much higher photocatalytic activity under visible-light irradiation (λ > 420 nm). The photocatalytic activity of the composite was related to impregnation time of the copper nitrate solution, and an optimal time was 2 h. The activity of 2-CuxO/TNTs displayed 4.9 times as high as that of pure TNTs. The enhanced photocatalytic performance is mainly attributed to the synergistic effects of initiating visible-light absorption and the matched band edge positions of Cu2O, CuO and TiO2. Also, a possible mechanism on the CuxO/TNTs photocatalytic degradation of RhB is proposed. Overall, the inexpensive and environmentally friendly photocatalyst, as promising materials, could be used to remove some aquatic pollutants in the field of water purification.