Browsing by Author "Liao, Chun-Yi"

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Enhanced photocatalytic activity of Cu-deposited N-TiO2/titanate nanotubes under UV and visible light irradiations
(2017-05-31)
Doong, Ruey-an
;
Liao, Chun-Yi
;
環境工程研究所
;
Institute of Environmental Engineering
A rapid and green synthesis of Cu-deposited N-doped TiO2/titanate nanotubes (TNTs) by the aid of microwave-assisted hydrothermal method was developed for the enhanced photocatalytic activity toward bisphenol A (BPA) degradation under UV and visible light irradiations. The TNTs are first synthesized at 150 degrees C for 3 h by microwave-assisted method followed by the calcination at 450 degrees C under NH3/N-2 atmosphere after the adsorption of 2-10 wt% Cu(II) ions to produce metallic Cu-deposited N-TiO2/TNTs nanocomposites. The microstructural analyses show that the Cu(II) ions are converted to Cu-0 in NH3/ N-2 with mean particle sizes of 39-42 nm and N atoms are incorporated into the lattices of TiO2/TNTs. The Cu-deposited N-TiO2/TNT nanocomposites show the superior photoactivity toward BPA degradation under both UV and visible light irradiations. The photodegradation efficiency and rate of BPA increases upon increasing Cu amount and the optimal mass loadings of 8-10 wt% are obtained. In addition, the pseudo-first-order rate constants for BPA degradation increase 5.3-6.8 and 2.1-3.0 times under UV and visible light irradiations, respectively, when compare with those of Degussa P25 TiO2. The Schottky barrier between Cu-0 and N-TiO2 promotes the electron transfer from N-doped TiO2 to metallic Cu nanoparticles under UV and visible light irradiations, resulting in the efficient generation of prolonged oxygen-containing radicals for enhanced photodegradation of BPA. Results obtained in this study clearly open a new pave for the green synthesis of 1-dimensional metal-metal oxide nanophotocatalysts which can be potentially used in the fields of purification, green chemistry and photocatalysis. (C) 2017 Elsevier B.V. All rights reserved.
Enhanced visible-light-responsive photodegradation of bisphenol A by Cu, N-codoped titanate nanotubes prepared by microwave-assisted hydrothermal method
(2017-01-15)
Doong, Ruey-An
;
Liao, Chun-Yi
;
環境工程研究所
;
Institute of Environmental Engineering
In this study, a rapid and effective microwave-assisted hydrothermal method was developed for the synthesis of Cu, N-codoped titanate nanotubes (Cu, N-TNTs) to enhance the photocatalytic degradation efficiency and rate of bisphenol A (BPA) under UV and visible light irradiations. The TNTs were first synthesized at 150 degrees C for 3 h under microwave heating conditions followed by the calcination at 450 degrees C in the presence of 6 wt% Cu ions and N-2/NH3 to fabricate Cu, N-TNTs composites. The Cu, N-TNTs exhibited excellent photocatalytic activity toward BPA degradation under UV and visible light irradiations. The X-ray photoelectron spectra indicated that Cu species in Cu, N-TNTs were mainly in zerovalent form and could serve as the electron donors as well as shuttling species to accelerate the photodegradation of BPA. In addition, the nitrogen atoms were incorporated into the anatase lattices to increase the visible light-responsive capability. The surface normalized reaction rate constants for BPA degradation were 4.3 and 1.5 times higher than those of Degussa P25 TiO2 under UV and visible light irradiations, respectively. The electron spin resonance spectra showed that Cu, N-codoped TNTs prolonged the generation of oxygen-containing radicals for at least 5 min, resulting in the significant enhancement of photodegradation efficiency and rate of BPA. Results obtained in this study open a new avenue by using simple and effective microwave-assisted hydrothermal method to fabricate low dimensional codoped TNTs which can be potentially applied in a wide variety of fields of purification, green chemistry and photocatalysis. (C) 2016 Elsevier B.V. All rights reserved.