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1.
In this work TiO2 thin films were modified with gold/palladium (Au/Pd) bimetallic paticles by sputtering method. TiO2 films were deposited on ITO (SnO2:In) by Doctor Blade method and post-anneling. The properties of the films were studied through measurements of XRD (X-ray diffraction) and AFM (atomic force microscopy). The degradation of methylene blue was studied by UV-irradiated pure TiO2 and Au/Pd-modified TiO2 in aqueous solution. Langmuir-Hinshelwood model was used to obtain kinetic information. Photocatalytic study indicated that Au/Pd-modified TiO2 photocatalytic activity was better than TiO2 pure; the best half-life time for Au/Pd-modified TiO2 in photodegradation was 2.8 times smaller than TiO2 pure; finally the efficiency in methylene blue photodegradation was improved from 23% to 43% when Au/Pd-modified TiO2 films were used.  相似文献   

2.
The build-up of intermediate species on the surface of TiO2 during gas-phase toluene (C7H8) photodegradation has been observed to deactivate the photocatalyst. Nanosized metallic deposits on the TiO2 surface may enhance the photocatalytic process and improve photocatalyst performance. In this study, noble (Ag, Au) and platinum group (Pt, Pd, Rh) metals, at a nominal loading of 0.5 at.%, were deposited onto Degussa P25 TiO2 to enhance photocatalyst performance and inhibit deactivation. Pd, Rh and Au deposits delayed photocatalyst deactivation by a factor of 2, while Pt deposits delayed photocatalyst deactivation by a factor of 20, when compared with neat TiO2. Ag deposits did not improve photocatalyst activity. Metal deposit performance was related to the work function of each metal, however, the Pt finding suggested that these effects are not governed solely by this aspect, but factors such as deposit characteristics and/or thermal catalytic properties of the metals may be influential.  相似文献   

3.
TiN/TiO2 nanoparticle photocatalyst was prepared by ball milling of TiO2 in H2O solution doped with TiN. The photocatalyst was characterized by UV–Vis diffuse reflection spectroscopy, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Based on the results of the characterization, the mechanism of the increase in photocatalytic activity was investigated. The results show that when the amount of doped TiN is 0.15 wt%, the photocatalytic activity of the TiN/TiO2 is at its peak. Compared with TiO2, the photoabsorption wavelength range of the TiN/TiO2 photocatalyst red-shifts about 30 nm, and the photoabsorption intensity increases as well. The photocatalytic activities of the photocatalyst are higher than that of TiO2 under UV and visible light irradiation. The increase of surface Ti3+ reactive center and the extension of the photoabsorption wavelength are the main factors for the increase in the photocatalytic activity of the TiN/TiO2. Doped TiN neither changes the TiO2 crystal phase nor creates new crystal phase by ball milling.  相似文献   

4.
TiO2 nanotubes were prepared by hydrothermal method and Au (or Pt) was loaded on TiO2 nanotubes by photodeposition method. The photocatalysts were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and N2 adsorption technique, respectively. The photocatalytic properties of the samples were also investigated. The results show that TiO2 nanotubes with uniform diameter were prepared, and they have specific surface areas over 400 m2/g. The specific surface areas of TiO2 nanotubes decrease with the increasing of calcining temperature, and crystalline phase of TiO2 in the wall of nanotubes was transformed from anatase into rutile phase in calcination process. The photocatalytic activities of TiO2 nanotubes are higher than that of nanosized TiO2, and the photocatalytic activities of TiO2 nanotubes were enhanced after loading Au (or Pt). After irradiation for 40 min under a 300 W of middle-pressure mercury lamp (MPML), the degradation rate of methyl orange solution using the Au/TiNT-500 (or Pt/TiNT-500) as a catalyst can reach 96.1% (or 95.1%). On the other hand, Au-loaded sample has evident adsorption peak in visible range, indicating that Au-loaded TiO2 nanotubes are hopeful to become visible light photocatalyst.  相似文献   

5.
Nitrogen and ferrum co-doped titania photocatalyst was prepared by the sol-gel route. The prepared photocatalyst was characterized by various techniques including X-ray diffraction (XRD), UV-vis diffusive reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and N2 adsorption-desorption isotherm. The photocatalytic activity of the co-doped titania photocatalyst was evaluated by the degradation of methyl orange (MO) from aqueous solution under visible light irradiation and was compared with that of the commercial TiO2 photocatalyst (Degussa P25). The results revealed that the nitrogen doping could lead to the response to visible light and that the ferrum doping could improve the photocatalytic performance. The effects of the component and the annealing temperature of the co-doped titania photocatalyst on the photocatalytic activity were investigated.  相似文献   

6.
Novel Pd/InVO4-TiO2 thin films with visible light photocatalytic activity were synthesized from the Pd and InVO2 co-doped TiO2 sol via sol-gel method. The photocatalytic activities of Pd/InVO4-TiO2 thin films were investigated based on the oxidative decomposition of methyl orange in aqueous solution. The as-prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and UV-vis absorption spectroscopy (UV-vis). The results indicate that the Pd/InVO4-TiO2 thin films are compact, uniform and consist of sphere nanoparticles with diameters about 80-100 nm. The UV-vis spectra show that the Pd/InVO4-TiO2 thin films extend the light absorption spectrum toward the visible region. XPS results reveal that doped Pd exist in the form of metallic palladium. The photocatalytic experiments demonstrate that Pd doping can effectively enhance the photocatalytic activities of InVO4-TiO2 thin films in decomposition of aqueous methyl orange under visible light irradiation. It has been confirmed that Pd/InVO4-TiO2 thin films could be excited by visible light (E < 3.2 eV) due to the existence of the Pd and InVO4 doped in the films.  相似文献   

7.
A series of photocatalysts TiO2/CFA were prepared using coal fly ash (CFA), waste discharged from coal-fired power plant, as substrate, and then these photocatalysts were characterized by scanning electron microscope, X-ray diffraction analysis, nitrogen adsorption test and ultraviolet-visible absorption analysis. The effects of loading percent of TiO2 on the photocatalytic activity and re-use property of TiO2/CFA were evaluated by the photocatalytic decoloration and mineralization of methyl orange solution. The results show that the pore volume and the specific surface area of the TiO2/CFA both increased with the increase in the loading percent of TiO2, which improved the photocatalytic activity of TiO2/CFA. However, when the loading percent of TiO2 was too high (up to 54.51%), superfluous TiO2 was easy to break away from CFA in the course of water treatment, which was disadvantaged to the recycling property of TiO2/CFA. In this study, the optimal loading percent of TiO2 was 49.97%, and the efficiencies of photocatalytic decoloration and mineralization could be maintained above 99% and 90%, respectively, when the photocatalyst was used repeatedly, without any decline, even at the sixth cycle.  相似文献   

8.
Photocatalysis of supported TiO2 film photocatalyst in a pulsed discharge system for phenol degradation was studied in this paper. The obtained results revealed that the supported TiO2 film with anatase structure had preferable photocatalytic activity in the pulsed discharge system. Phenol degradation and main byproduct generation were better in the discharge/TiO2 system. The photocatalyst prepared with eight times dipping process had higher photocatalytic activity than other photocatalysts and testified a preferable photocatalyst condition in the pulsed discharge system. Furthermore, the supported TiO2 photocatalyst kept photocatalytic activity after using five times in the pulsed discharge system.  相似文献   

9.
高攀  吴晶  柳清菊  周文芳 《中国物理 B》2010,19(8):87103-087103
The crystal structures, electronic structures and optical properties of nitrogen or/and praseodymium doped anatase TiO2 were calculated by first principles with the plane-wave ultrasoft pseudopotential method based on density functional theory. Highly efficient visible-light-induced nitrogen or/and praseodymium doped anatase TiO2 nanocrystal photocatalyst were synthesized by a microwave chemical method. The calculated results show that the photocatalytic activity of TiO2 can be enhanced by N doping or Pr doping, and can be further enhanced by N+Pr codoping. The band gap change of the codoping TiO2 is more obvious than that of the single ion doping, which results in the red shift of the optical absorption edges. The results are of great significance for the understanding and further development of visible-light response high activity modified TiO2 photocatalyst. The photocatalytic activity of the samples for methyl blue degradation was investigated under the irradiation of fluorescent light. The experimental results show that the codoping TiO2 photocatalytic activity is obviously higher than that of the single ion doping. The experimental results accord with the calculated results.  相似文献   

10.
In order to improve visible light photocatalytic activities of the nanometer TiO2, a novel and efficient Cr,S-codoped TiO2 (Cr-TiO2-S) photocatalyst was prepared by precipitation-doping method. The crystalline structure, morphology, particle size, and chemical structure of Cr-TiO2-S were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) techniques, respectively. Results indicate that the doping of Cr and S, cause absorption edge shifts to the visible light region (λ > 420 nm) compare to the pure TiO2, reduces average size of the TiO2 crystallites, enhances desired lattice distortion of Ti, promotes separation of photo-induced electron and hole pair, and thus improves pollutant decomposition under visible light irradiation. The photocatalytic activities of Cr-TiO2-S nanoparticles were evaluated using the photodegradation of methyl orange (MO) as probe reaction under the irradiation of UV and visible light and it was observed that the Cr-TiO2-S photocatalyst shows higher visible photocatalytic activity than the pure TiO2. The optimal Cr-TiO2-S concentration to obtain the highest photocatalytic activity was 5 mol% for both of Cr and S.  相似文献   

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