Photocatalytic Degradation of NOx Over Platinum and Nitrogen Codoped Titanium Dioxide Under Visible Light Irradiation

2007 ◽  
Vol 72 (3) ◽  
pp. 379-391 ◽  
Author(s):  
Lin Zhou ◽  
Xin Tan ◽  
Lin Zhao ◽  
Ming Sun

In order to utilize visible light and enhance the catalytic efficiency in photocatalytic conversion of NOx, nitrogen and platinum atoms were doped in commercially available photocatalytic TiO2 powders by impregnating and photodeposition methods, respectively. X-ray diffraction (XRD) showed that the crystal structures of TiO2 were not changed after the doping process. Analysis by X-ray photoelectron spectroscopy (XPS) indicated that N atoms were incorporated in the bulk phase of TiO2 as N-Ti-O linkages and Pt atoms were at the surface. A significant shift of the absorption edge to lower energy and higher absorption in the visible light region were observed. This Pt,N-codoped TiO2 powder exhibited excellent photocatalytic activity and fairly stable chemical property for the degradation of NOx under visible light irradiation. The sample mixed with 20 wt.% ammonium carbonate and doped with 0.5 at.% platinum atoms showed the best photocatalytic activity and its activity can be restored by rinsing with water after long-term operation.

2011 ◽  
Vol 287-290 ◽  
pp. 1640-1645 ◽  
Author(s):  
Min Guang Fan ◽  
Zu Zeng Qin ◽  
Zi Li Liu ◽  
Tong Ming Su

A series of BixY(2-x)O3photocatalysts were successfully prepared by a solid-state reaction and were subsequently characterized by powder X-ray diffraction, UV-vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The UV-vis diffuse reflectance spectra revealed that the BixY(2-x)O3samples absorbed light in the visible-light range (400-800 nm). The XPS results indicated that active oxygen species were generated on the Bi1.8Y0.2O3surface, which displayed a higher photocatalytic activity. When using photocatalytic degradation molasses fermentation wastewater as a model reaction, the Bi1.8Y0.2O3showed higher photocatalytic activity in comparison to Bi0.2Y1.8O3under visible-light irradiation.


2013 ◽  
Vol 690-693 ◽  
pp. 511-517 ◽  
Author(s):  
Xi Kang ◽  
Jing Qi ◽  
Long Ye ◽  
Hong You ◽  
Li Jiang Hu

Ag⁄N co–doped TiO2 nanotube arrays (TNTs) were prepared by anodic oxidation, a certain amount of Ag deposited on the surface of TNTs by photodeposition and annealing post-treatment. The doped TNTs were characterized by field-emission scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis diffusion reflection spectroscopy (UV–vis DRS). The photocatalytic activities of the prepared TiO2 were evaluated by degrading rhodamine B (RhB) under visible light irradiation (≤ 420 nm). The photocatalytic degradation efficiency of the Ag/N-TNTs obtained for the degradation of RhB are 0.32 times, 0.6 times and 1.86 times higher than that of TNTs, N–TNTs, AgTNTs, respectively.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Quan Gu ◽  
Huaqiang Zhuang ◽  
Jinlin Long ◽  
Xiaohan An ◽  
Huan Lin ◽  
...  

The C-doped CdO photocatalysts were simply prepared by high-temperature solid-state process. The as-prepared photocatalysts were characterized by X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the carbon was doped into CdO, resulting in the red-shift of the optical absorption of CdO. The photocatalytic behavior of CdO and C-doped CdO was evaluated under the visible light irradiation by using the photocatalytic hydrogen evolution as a model reaction. The C-doped CdO photocatalysts had higher photocatalytic activity over parent CdO under visible light irradiation. The results indicated that the H2production was due to the existence of CdS and the enhancement of visible light photocatalytic activity of H2production was originated from the doping of carbon into the CdO lattice. The probably reaction mechanism was also discussed and proposed.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Min Zhang ◽  
Juan Wu ◽  
DanDan Lu ◽  
Jianjun Yang

A series of W, N codoped TiO2nanotube arrays with different dopant contents were fabricated by anodizing in association with hydrothermal treatment. The samples were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and ultraviolet-visible light diffuse reflection spectroscopy. Moreover, the photocatalytic activity of W and N codoped TiO2nanotube arrays was evaluated by degradation of methylene blue under visible light irradiation. It was found that N in codoped TNAs exists in the forms of Ti-N-O, while W exists as W6+by substituting Ti in the lattice of TiO2. In the meantime, W and N codoping successfully extends the absorption of TNAs into the whole visible light region and results in remarkably enhanced photocatalytic activity under visible light irradiation. The mechanism of the enhanced photocatalytic activity could be attributed to (i) increasing number of hydroxyl groups on the surface of TNAs after the hydrothermal treatment, (ii) a strong W-N synergistic interaction leads to produce new states, narrow the band gap which decrease the recombination effectively, and then greatly increase the visible light absorption and photocatalytic activity; (iii) W ions with changing valences in all codoped samples which are considered to act as trapping sites, effectively decrease the recombination rate of electrons and holes, and improve the photocatalytic activity.


Author(s):  
Uyi Sulaeman ◽  
Bin Liu ◽  
Shu Yin ◽  
Tsugio Sato

The highly active Ag3PO4 photocatalysts were successfully synthesized using the hydrophylic polymer of PVA (polyvinyl alcohol), PEG (polyethylene glycol) and PVP (polyvinyl pyrrolidone). The products were characterized using X-ray diffraction (XRD), Diffuse reflection spectroscopy (DRS), Field emission scanning electron microscope (FE-SEM), Brunauer–Emmett–Teller (BET) specific surface area, and X-ray photoelectron spectroscopy (XPS). Photocatalytic activities were evaluated using decomposition of Rhodamine B (RhB) under visible light irradiation. The results showed that the PVA, PEG, and PVP increased the specific surface area and enhanced the photocatalytic activity of Ag3PO4. The highest photocatalytic activity could be observed in Ag3PO4 synthesized with PVA, mainly due to an increase in electron excitation induced by PVA chemically adsorbed on the surface. Copyright © 2017 BCREC Group. All rights reservedReceived: 13rd November 2016; Revised: 10th February 2017; Accepted: 10th February 2017How to Cite: Sulaeman, U., Liu, B., Yin, S., Sato, T. (2017). Synthesis of Ag3PO4 using Hydrophylic Polymer and Their Photocatalytic Activities under Visible Light Irradiation. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2): 206-211 (doi:10.9767/bcrec.12.2.767.206-211)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.767.206-211 


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Gang-Juan Lee ◽  
Chi-Lun Hong ◽  
Valentina Batalova ◽  
Gennady Mokrousov ◽  
Jerry Wu

Nitrogen modified zinc sulfide photocatalysts were successfully prepared and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and surface area analysis. Thermal decomposition of the semisolid was carried out under nitrogen conditions at 500°C for 2 hours, and a series of nitrogen-doped ZnS photocatalysts were produced by controlling inflow flow rate of nitrogen at 15–140 mL/min. Optical characterizations of the synthesized N-doping ZnS substantially show the shifted photoabsorption properties from ultraviolet (UV) region to visible light. The band gaps of nitrogen-doped ZnS composite catalysts were calculated to be in the range of 2.58~2.74 eV from the absorptions edge position. The 15N/ZnS catalyst shows the highest photocatalytic activity, which results in 75.7% degradation of Orange II dye in 5 hrs by visible light irradiation, compared with pristine ZnS and higher percentage N-doping ZnS photocatalysts.


2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Hang Nguyen Thai Phung ◽  
Van Nguyen Khanh Tran ◽  
Lam Thanh Nguyen ◽  
Loan Kieu Thi Phan ◽  
Phuong Ai Duong ◽  
...  

MoS2/TiO2 heterostructure thin films were fabricated by sol-gel and chemical bath deposition methods. Crystal structure, surface morphology, chemical states of all elements, and optical property of the obtained thin films were characterized by using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy techniques, respectively. Photocatalytic activity of all thin films was evaluated by measuring decomposition rate of methylene blue solution under visible light irradiation. The results indicate that ultrathin MoS2 film on TiO2-glass substrate improves photocatalytic activity of TiO2 in the visible light due to the efficient absorption of visible photon of MoS2 few layers and the transfer of electrons from MoS2 to TiO2. All MoS2/TiO2 heterostructure thin films exhibit higher visible light photocatalytic activity than that of pure MoS2 and TiO2 counterparts. The best MoS2/TiO2 heterostructure thin film at MoS2 layer deposition time of 45 minutes can decompose about 60% MB solution after 150 minutes under visible light irradiation. The mechanism of the enhancement for visible-photocatalytic activity of MoS2/TiO2 heterostructure thin film was also discussed.


2011 ◽  
Vol 335-336 ◽  
pp. 1385-1390 ◽  
Author(s):  
Shuo Wiei Zhao ◽  
Hui Xu ◽  
Hua Ming Li ◽  
Yuan Guo Xu

In order to improve the photocatalytic activity, Co was successfully loaded into Ag3VO4 by using impregnation process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS). The XRD and SEM–EDS analyses revealed that Co ion was dispersed on Ag3VO4. The DRS results indicated that the absorption edge of the Co–Ag3VO4 catalyst shifted to longer wavelength. The enhanced photocatalytic activity of Co–Ag3VO4 for Methylene Blue(MB) dye degradation under visible light irradiation was due to its wider absorption edge and higher separation rate of photo-generated electron and holes. In the experimental conditions, it is demonstrated that the MB was effectively degraded by more than 95% within 40 min when the Co–Ag3VO4 catalyst was calcined at 300°C with 1 wt.% Co content.


2014 ◽  
Vol 787 ◽  
pp. 35-40 ◽  
Author(s):  
Xiao Yan Zhou ◽  
Peng Wei Zhou ◽  
Hao Guo ◽  
Bo Yang ◽  
Ru Fei Ren

The p-n junction photocatalysts, p-CuO (at. 0-25%)/n-ZnO nanocomposite were prepared through hydrothermal method without using any organic solvent or surfactant. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-Ray spectroscopy, and UV-vis spectroscopy. The results demonstrated that the CuO/ZnO nanocomposite presented a two-dimensional morphology composed of sheet-like ZnO nanostructures adorned with CuO nanoparticles. The photocatalytic activity of CuO/ZnO with different Cu/Zn molar rations and pure ZnO synthesized by the identical synthetic route were evaluated by degrading methylene blue (MB) dye under UV-visible light irradiation. The CuO/ZnO with Cu/Zn molar ratio of 4% exhibits the highest photocatalytic activity compared that of the other photocatalysts under the identical conditions. It is mainly attributed to the increased charge separation rate in the nanocomposite and the extended photo-responding range.


Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 105 ◽  
Author(s):  
Huiting Wang ◽  
Jin Mao ◽  
Zhaowei Zhang ◽  
Qi Zhang ◽  
Liangxiao Zhang ◽  
...  

Deoxynivalenol (DON) is a secondary metabolite produced by Fusarium, which is a trichothecene mycotoxin. As the main mycotoxin with high toxicity, wheat, barley, corn and their products are susceptible to contamination of DON. Due to the stability of this mycotoxin, traditional methods for DON reduction often require a strong oxidant, high temperature and high pressure with more energy consumption. Therefore, exploring green, efficient and environmentally friendly ways to degrade or reduce DON is a meaningful and challenging issue. Herein, a dendritic-like α-Fe2O3 was successfully prepared using a facile hydrothermal synthesis method at 160 °C, which was systematically characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). It was found that dendritic-like α-Fe2O3 showed superior activity for the photocatalytic degradation of DON in aqueous solution under visible light irradiation (λ > 420 nm) and 90.3% DON (initial concentration of 4.0 μg/mL) could be reduced in 2 h. Most of all, the main possible intermediate products were proposed through high performance liquid chromatography-mass spectrometry (HPLC-MS) after the photocatalytic treatment. This work not only provides a green and promising way to mitigate mycotoxin contamination but also may present useful information for future studies.


Sign in / Sign up

Export Citation Format

Share Document