Microwave-assisted synthesis of Ag 2 O/reduced TiO 2 nano-tube arrays photoelectrode with enhanced visible photocatalytic activity for degradation of organic pollutants

Abstract

Abstract In order to improve the charge separation and photocatalytic (PC) efficiency of TiO 2 nano-tube arrays (TiO 2 NTAs) photoelectrode, narrower band gap Ag 2 O nano-crystallites decorated reduced TiO 2 NTAs (Ag 2 O/r-TiO 2 NTAs) photoelectrode was fabricated through one-step microwave reduction strategy, which could simultaneously induce the generation of Ag 2 O nano-crystallites onto the surface of TiO 2 NTAs and Ti 3+ self-doping energy level below the conduction band of TiO 2 . Subsequently, the resulting photoelectrodes were systematically studied by scanning electron spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV–visible light diffuse reflectance spectroscopy and photoelectrochemical measurements. In addition, the photocatalytic (PC) performance was evaluated by photodecomposition of methyl blue and generation of OH radicals. As a result, Ag 2 O/r-TiO 2 NTAs photoelectrode performed a significantly enhanced light absorbance in the whole visible region, transient photocurrent density of 0.189 mA cm −2 , photoinduced charge separation efficiency and 98.9% of PC efficiency for decomposition of methyl blue. Furthermore, the enhanced visible light PC mechanism for decomposition of organic pollutant was proposed, which was mainly attributed to the strong visible light absorbance and high photoinduced charge separation efficiency. Moreover, the as-fabricated Ag 2 O/r-TiO 2 NTAs photoelectrode performed well stability after consecutive utilization for five cycles. This study provides a versatile strategy to fabricate high-efficient catalyst which could be utilized in waste water elimination.