scholarly journals One-Step Cohydrothermal Synthesis of Nitrogen-Doped Titanium Oxide Nanotubes with Enhanced Visible Light Photocatalytic Activity

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Cheng-Ching Hu ◽  
Tzu-Chien Hsu ◽  
Li-Heng Kao

Nitrogen-doped TiO2nanotubes with enhanced visible light photocatalytic activity have been synthesized using commercial titania P25 as raw material by a facile P25/urea cohydrothermal method. Morphological and microstructural characteristics were conducted by transmission electron microscopy, powder X-ray diffraction, and nitrogen adsorption/desorption isotherms; chemical identifications were performed using X-ray photoelectron spectroscopy, and the interstitial nitrogen linkage to the TiO2nanotubes is identified. The photocatalytic activity of nitrogen-doped TiO2nanotubes, evaluated by the decomposition of rhodamine B dye solution under visible light using UV-vis absorption spectroscopy, is found to exhibit ~ four times higher than that of P25 and undoped titanate nanotubes. Factors affecting the photocatalytic activity are analyzed; it is found that the nitrogen content and surface area, rather than the crystallinity, are more crucial in affecting the photocatalytic efficiency of the nitrogen-doped TiO2nanotubes.

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Xiuwen Cheng ◽  
Xiujuan Yu ◽  
Zipeng Xing ◽  
Lisha Yang

Anatase mesoporous titanium dioxide codoped with nitrogen and chlorine (N-Cl-TiO2) photocatalysts were synthesized through simple one-step sol-gel reactions in the presence of ammonium chloride. The resulting materials were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS). XRD results indicated that codoping with nitrogen and chlorine could effectively retard the phase transformation of TiO2from anatase to rutile and the growth of the crystallite sizes. XPS revealed that nitrogen and chlorine elements were incorporated into the lattice of TiO2through substituting the lattice oxygen atoms. DRS exhibited that the light absorption of N-Cl-TiO2in visible region was greatly improved. As a result, the band gap of TiO2was reduced to 2.12 eV. The photocatalytic activity of the as-synthesized TiO2was evaluated for the degradation of RhB and phenol under visible light irradiation. It was found that N-Cl-TiO2catalyst exhibited higher visible light photocatalytic activity than that of P25 TiO2and N-TiO2, which was attributed to the small crystallite size, intense light absorption in visible region, and narrow band gap.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Biying Li ◽  
Xiuwen Cheng ◽  
Xiujuan Yu ◽  
Lei Yan ◽  
Zipeng Xing

Fe-N-S-tri-dopedTiO2photocatalysts were synthesized by one step in the presence of ammonium ferrous sulfate. The resulting materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflection spectrum (UV-Vis DRS). XPS analysis indicated that Fe (III) and S6+were incorporated into the lattice ofTiO2through substituting titanium atoms, and N might coexist in the forms of substitutional N (O-Ti-N) and interstitial N (Ti-O-N) in tridopedTiO2. XRD results showed that tri-doping with Fe, N, and S elements could effectively retard the phase transformation ofTiO2from anatase to rutile and growth of crystallite size. DRS results revealed that the light absorbance edge ofTiO2in visible region was greatly improved by tri-doping with Fe, N, and S elements. Further, the photocatalytic activity of the as-synthesized samples was evaluated by the degradation of phenol under visible light irradiation. It was found that Fe-N-S-tri-dopedTiO2catalyst exhibited higher visible light photocatalytic activity than that of pureTiO2and P25TiO2, which was mainly attributed to the small crystallite size, intense light absorbance in visible region, and narrow bandgap energy.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Min Fu ◽  
Jiazhen Liao ◽  
Fan Dong ◽  
Hongmei Li ◽  
Hongyan Liu

Novel visible light photocatalytic graphitic carbon nitride/TiO2(g-C3N4/TiO2) composite samples were synthesized by heating mixtures of melamine and commercial TiO2(TO) at different weight ratios. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), Fourier transform infrared spectroscopy (FTIR), and UV-visible diffused reflectance spectroscopy (UV-vis DRS). Characterization confirms formation of nanocomposites of g-C3N4/TiO2. At the optimized precursor weight ratio (melamine:mTiO2=2.5), the samples exhibited highest adsorption capacity and visible light photocatalytic activity, measured by degradation of methylene blue (MB). Under visible light irradiation, the excited electrons on the surface of g-C3N4transfer easily to the conduction band (CB) of TiO2via the well-built heterojunction. The g-C3N4/TiO2nanocomposites exhibit enhanced visible light catalytic activity due to increased visible light adsorption and effective separation of photogenerated electron-hole pairs. These g-C3N4/TiO2nanocomposites could find broad applicability in environmental protection due to their excellent visible light photocatalytic property and facile, cost-effective preparation process.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Xinlei Zhang ◽  
Juan Zhou ◽  
Yufen Gu ◽  
Ding Fan

Highly ordered nitrogen-doped titanium dioxide (N-doped TiO2) nanotube arrays were prepared by anodic oxidation method and then annealed in a N2atmosphere to obtain N-doped TiO2nanotube arrays. The samples were characterized with scanning electron microscope (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectrum (XPS), and UV-visible spectrophotometry (UV-vis) spectrum. Degradation of the insecticide acephate under the visible light was used as a model to examine the visible-light photocatalytic activity of N-doped TiO2nanotube arrays. The results show that N type doping has no notable effects on the morphology and structure of TiO2nanotube arrays. After N type doping, the N replaces a small amount of O in TiO2, forming an N–Ti–O structure. This shifts the optical absorption edge and enhances absorption of the visible light. N-doped TiO2nanotube arrays subjected to annealing at 500°C in N2atmosphere show the strongest photocatalytic activity and reach a degradation rate of 84% within 2 h.


2014 ◽  
Vol 16 (26) ◽  
pp. 13409-13417 ◽  
Author(s):  
Chao Liu ◽  
Liang Wu ◽  
Jing Chen ◽  
Ji-yuan Liang ◽  
Chang-shun Li ◽  
...  

N-doping and intercalation resulted in a PANI–N-HTiNbO5lamellar nanocomposite, which showed a dramatic enhanced visible-light photocatalytic activity and stability for the degradation of methylene blue (MB), due to the high efficiency of charge separation.


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