A facile strategy to fabricate reduced TiO2 nano-tube arrays photoelectrode and its high visible light photocatalytic performance for detoxification of trichlorophenol solution

Abstract

Abstract In the research, reduced TiO2 nano-tube arrays (denoted as R-TiO2 NTAs) photoelectrode was successfully fabricated by potassium borohydride (PBH) reduction treatment. Afterwards, the as-fabricated photoelectrode was characterized by scanning electron microscope, X-ray diffraction, Raman spectra and electron spin resonance. Meanwhile, the optical and photoelectrochemical properties of R-TiO2 NTAs photoelectrode were also studied through ultraviolet-visible diffuse reflectance spectroscopy and transient photocurrent response, respectively. The photocatalytic (PC) activity of R-TiO2 NTAs photoelectrode was measured by degradation of trichlorophenol (TCP). Moreover, the change of toxic intermediates in the process of degradation TCP was further evaluated by photobacterium inhibition tests. Results suggested that an impurity level can be induced in the TiO2 NTAs band gap by solution reduction treatment due to the generation of Ti3+ and oxygen vacancies (Ov). Furthermore, R-TiO2 NTAs photoelectrode exhibited higher PC activities than that of pristine TiO2 NTAs owing to the enhancement of visible light harvesting between 450 and 800 nm and separation efficiency of photogenerated electrons-holes (e/h+) pairs. The possible pathway for TCP degradation and photocatalytic mechanism were also proposed and confirmed. Furthermore, R-TiO2 NTAs photoelectrode displayed good stability and reusability.