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Sm(3+)-doped TiO(2) nanocrystalline has been prepared by sol-gel auto-combustion technique and characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, and also UV-vis diffuse reflectance spectroscopy (DRS). These Sm(3+)-doped TiO(2) samples were tested for methylene blue (MB) decomposition and *OH radical formation. The analysis of *OH radical formation on the sample surface under UV irradiation was performed by fluorescence technique with using terephthalic acid, which readily reacted with *OH radical to produce highly fluorescent product, 2-hydroxyterephthalic acid. It was observed that the presence of Sm(3+) ion as a dopant significantly enhanced the photocatalytic activity for MB degradation under UV light irradiation because both the larger specific surface area and the greater the formation rate of *OH radical were simultaneously obtained for Sm(3+)-doped TiO(2) nanocrystalline. The adsorption experimental demonstrated that Sm(3+)-TiO(2) had a higher MB adsorption capacity than undoped TiO(2) and the adsorption capacity of MB increased with the increase of samarium ion content. The results also indicated that the greater the formation rate of *OH radical was, the higher photocatalytic activity was achieved. In this study, the optimum amount of Sm(3+) doping was 0.5 mol%, at which the recombination of photo-induced electrons and holes could be effectively inhibited, the highest formation rate of *OH radicals was, and thereby the highest photocatalytic activity was achieved. 相似文献
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Multi-modal mesoporous TiO(2)-ZrO(2) composites with high photocatalytic activity and hydrophilicity
Utilizing the amphiphilic triblock copolymer Pluronic P123 as the surfactant, and Ti(O(n)Bu)(4) and ZrOCl(2)·8H(2)O as the inorganic sources, a series of multi-modal mesoporous TiO(2)-ZrO(2) composites have been successfully synthesized through a one-step method. The resultant materials were characterized in detail by x-ray diffraction, atomic force microscopy, high resolution scanning electron microscopy, transmission electron microscopy, N(2) adsorption and water contact angle measurements. The effect of calcination temperatures on the physical parameters, hydrophilicity and photocatalytic activity of the obtained mesoporous TiO(2)-ZrO(2) composites was also investigated in this paper. 相似文献
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Nano-TiO2 powder was prepared by sol-gel method with modified precursor, tetrabutyl titanate (TBT), and photocatalytic oxidation was applied in removal of organics in the powder. The microstructure of as-prepared nano-TiO2 was determined using UV-vis, TEM, XRD and BET. The results indicated that the nano-TiO2, with grain size of 3.8 nm and specific surface area of 359.1 m2/g, was composed of anatase alone, and that it exhibited significant blue-shift in its UV-vis spectrum. The decomposition of organics in the sample was systematically investigated using FT-IR and TG-DTA. According to the testing results, we could conclude that organics in the samples were completely eliminated by means of photocatalytic oxidation. With photocatalytic decoloration of active brilliant red X-3B in aqueous solution as model reaction, the photocatalytic activity of as-prepared nano-TiO2 was investigated and was compared with that of the samples experiencing heat treatment and Degussa P-25 as well. The experimental results indicated that the photoactivity of as-prepared nano-TiO2 is much higher than that of the samples experiencing heat treatment. 相似文献
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H(2)O(2)-sensitized TiO(2)/SiO(2) composites with high photocatalytic activity under visible irradiation 总被引:1,自引:0,他引:1
TiO(2)/SiO(2) composite photocatalysts were prepared by depositing of TiO(2) onto nano-SiO(2) particles. X-ray diffraction (XRD), transmission electron micrograph (TEM), Raman spectrometer, UV-Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the properties of the synthesized TiO(2)/SiO(2) composites. These results indicated that the products without calcination were amorphous, and calcination could enhance the crystallinity of TiO(2). Increases in the amount of TiO(2) would decrease the dispersion in the composites. H(2)O(2)-sensitized TiO(2)/SiO(2) composite photocatalysts could absorb visible light at wavelength below 550 nm. The photocatalytic activity of as-prepared catalysts was characterized by methyl-orange degradation. The results showed the uncalcined composite photocatalysts with amorphous TiO(2) exhibited higher photocatalytic activity under visible light, and the activity of catalysts with TiO(2) content over 30% decreased with increasing of TiO(2) content. Increases in the calcination temperature and TiO(2) content promote the formation of bulk TiO(2) and result in a decrease in activity. 相似文献
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Nitrogen-doped titanium dioxide powders were prepared by wet method, that is, the hydrolysis of acidic tetra-butyl titanate using aqueous ammonia solution, followed by calcination at temperatures about 350 degrees C. The catalysts exhibited photocatalytic activity in the visible light region owing to N-doping. The light absorption onset of TiO(2-x)N(x) was shifted to the visible region at 459 nm compared to 330 nm of pure TiO(2). An obvious decrease in the band gap was observed by the optical absorption spectroscopy, which resulted from N2p localized states above the valence band of TiO(2-x)N(x) (compared to TiO(2)). The TiO(2-x)N(x) catalyst was characterized to be anatase with oxygen-deficient stoichiometry by X-ray diffraction (XRD), surface photovoltage spectroscopy (SPS) and X-ray photoelectron spectroscopy (XPS). The binding energy of N1s measured by XPS characterization was 396.6 eV (TiN bonds, beta-N) and 400.9 eV (NN bonds, gamma-N(2)), respectively. The photocatalytic activity of TiO(2-x)N(x) under visible light was induced by the formation of beta-N in the structure. Photocatalytic decomposition of benzoic acid solutions was carried out in the ultraviolet and visible (UV-vis) light region, and the TiO(2-x)N(x) catalyst showed higher activity than pure TiO(2). 相似文献
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Wijayarathna TR Aponsu GM Ariyasinghe YP Premalal EV Kumara GK Tennakone K 《Nanotechnology》2008,19(48):485703
Dye-sensitized photoelectrochemical solar cells made from nanocrystalline films of TiO(2) doped with copper and sensitized with indoline 149 dye are found to have impressively higher efficiencies compared to equivalent cells made from undoped films. The surface concentration of copper atoms on the TiO(2) where this effect is optimized is nearly the same as the concentration of dye molecules on the TiO(2) surface. Copper doping shifts the flat-band potential of TiO(2) in the negative direction, which is favorable for increasing the open-circuit voltage of the cell. It is suggested that in addition to the linkage of the carboxylate ligand of the dye to the TiO(2) surface, moieties in the rhodanine rings of the dye coordinate to the copper atoms on the TiO(2) surface. The coordination of the dye to copper seems to have a positive influence on the efficiency of the cell. 相似文献
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TiO2/Bi2S3 heterojunctions with a nuclear-shell structure were prepared by the coprecipitation method. The products were characterized by X-ray diffraction analysis, Raman spectra, transmission electron microscope images and energy dispersion X-ray spectra. Results showed that as-prepared Bi2S3 was urchin-like, made from many nanorods, and TiO2/Bi2S3 heterojunctions have a similar nuclear-shell structure, with Bi2S3 as the shell and TiO2 as the nuclear. The photocatalytic experiments performed under UV irradiation using methyl orange as the pollutant revealed that the photocatalytic activity of TiO2 could be improved by introduction of an appropriate amount of Bi2S3. However, excessive amount of Bi2S3 would result in the decrease of photocatalytic activity of TiO2. The relative mechanism was proposed. 相似文献
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Changlin Yu Longfu Wei Xin Li Jianchai Chen Qizhe Fan Jimmy C. Yu 《Materials Science and Engineering: B》2013,178(6):344-348
Square-like B doped TiO2 nanocrystals were first synthesized by a mild solvothermal method with H3BO4 and titanium isopropoxide as the precursors, and isopropyl alcohol as reaction medium. Then, Ag nanoparticles were deposited on TiO2-B nanosquares by photo-deposition. The as-synthesized products have been investigated by photocatalytic reaction test and characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectra (DRS). The results showed that boron was successfully doped into TiO2 nanosquares under solvothermal condition. The obtained Ag/TiO2-B composite showed high efficiency in degradation of acid orange II under visible light irradiation. The high photocatalytic performance could be attributed to the synergistic effect of B doping and the plasmon photocatalysis role of the deposited silver nanoparticles over TiO2. 相似文献
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Pavasupree S Ngamsinlapasathian S Suzuki Y Yoshikawa S 《Journal of nanoscience and nanotechnology》2006,6(12):3685-3692
High surface area nanosheet TiO2 with mesoporous structure were synthesized by hydrothermal method at 130 degrees C for 12 h. The samples characterized by XRD, SEM, TEM, SAED, and BET surface area. The nanosheet structure was slightly curved and approximately 50-100 nm in width and several nanometers in thickness. The as-synthesized nanosheet TiO2 had average pore diameter about 3-4 nm. The BET surface area and pore volume of the sample were about 642 m(2)/g and 0.774 cm(3)/g, respectively. The nanosheet structure after calcinations were changed into nanorods/nanoparticles composite with anatase TiO2 structure at 300-500 degrees C (10-15 nm in rods diameter and about 5-10 nm in particles diameter). The solar energy conversion efficiency (eta) of the cell using nanorods/nanoparticles TiO2 (from the nanosheet calcined at 450 degrees C for 2 h) with mesoporous structure was about 7.08% with Jsc of 16.35 mA/cm(2), Voc of 0.703 V and ff of 0.627; while eta of the cell using P-25 reached 5.82% with Jsc of 12.74 mA/cm(2), Voc of 0.704 V, and ff of 0.649. 相似文献
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Koichiro Hayashi Michihiro Nakamura Yoji Makita Rise Fujiwara Toshinari Kori Kazunori Ishimura 《Materials Letters》2011,65(19-20):3037-3040
Sea urchin-shaped rutile nanostructures (SUR NSs) with abundant {110} surfaces are synthesized at 60 °C under atmospheric pressure. The SUR NSs were ~ 420 nm in diameter and contain a number of needle-like rutile single crystals grown parallel to the (110) face from a single nucleus in a radial fashion. The photocatalytic activity of the SUR NSs is significantly higher than that of commercial rutile nanoparticles with the same specific surface area. This demonstrates that {110} facets are effective in enhancing photoactivity. 相似文献
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将微晶纤维素溶解于NaOH-尿素的低温溶液中形成纤维素溶液,在水浴中再生形成纳米纤维素溶液.然后将纳米纤维素溶液与TiO2(P25)混合,并添加少量的钛酸正丁酯作为交联剂形成复合溶液.将制备得到的复合溶液通过流延法固载到玻璃片表面形成玻璃固载的TiO2/纳米纤维素复合膜.通过SEM、XRD表征了复合膜的形貌与结构.将玻璃固载的TiO2/纳米纤维素复合膜在紫外光下进行光催化降解甲基橙(MO)以评估复合膜的光催化性能,研究了纳米TiO2含量对复合膜光催化性能的影响,复合膜的重复使用性能以及光降解的动力学过程.结果表明:复合膜对MO的光催化降解能力可达90%以上,与纯TiO2粉末相当,并重复使用3次光催化性能基本保持不变.复合膜对甲基橙的降解动力学符合一级动力学特征.当纳米TiO2相对于纤维素的质量分数为33.3%时,光催化活性最高,动力学速率常数为0.035min-1. 相似文献
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Xiangchen Kong Huiming Huang Zhaoyang Li Yanqin Liang Zhenguo Li Shengli Zhu 《材料科学技术学报》2021,80(21):171-178
TiO2 (B) nanosheets/GO (graphene oxide) hybrids are considered to be outstanding performance pho-tocatalysts for high efficiency of H2 evolution.However,they still suffer severe challenges during the synthetic processes,such as a large amount of the capping agents adhering on the surface and easy occurrence of aggregation.To figure out these obstacles,Ar plasma treatment as a modified method in this study not only enable the TiO2 (B) nanosheets distributed uniformly on the GO sheets but also engi-neer defects within TiO2 (B) nanosheetsto significantly improve the photocatalytic activity for the water splitting.The hydrogen evolution rate of the TiO2-x (B)/GO sheets is 1.4 times higher compared with that of original TiO2 (B)/GO sheets without Ar plasma treatment.The improved photocatalytic proper-ties were owing to the synergetic effects of oxygen vacancies and the heterojunction between GO and TiO2 (B),which can promote the visible light utilization and accelerate separation and transportation of photogenerated electron-holes.This study can provide a facile pathway to prepare the two-dimensional hybrid photocatalysts with high photocatalytic H2 activity. 相似文献
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Ji-An Cha Sang-Hun An Hee-Dong Jang Chan-Soo Kim Dong-Keun Song Tae-Oh Kim 《Advanced Powder Technology》2012,23(6):717-723
Visible-light responsive N-doped ZrO2/TiO2 photocatalysts were synthesized via a sol–gel process. To obtain the optimum nitrogen doping content and operational conditions for photodegradation of NO, several key factors (including nitrogen doping, initial NO concentration, light intensity, reactor temperature, etc.) were investigated under both UV and visible light irradiation. Physical characterization of the photocatalysts was performed using X-ray diffraction (XRD), UV–visible absorption spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). The observed results suggest that nitrogen was doped in the lattice of TiO2 and had an effect on the translation of phase, photodegradation activity, and visible-light response. Among synthesized photocatalysts, 0.1 M Zr and 0.15 M N supported on TiO2 exhibited the best visible-light response and the highest NO photodegradation activity. 相似文献
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Li Zhengguang Liu Xiangchun Bai Ningna Wu Qi Zhang Kai 《Journal of Materials Science: Materials in Electronics》2021,32(11):14456-14463
Journal of Materials Science: Materials in Electronics - In order to combine ZnWO4 and TiO2 to form a heterojunction, a sol–gel method combined with a hydrothermal method was used to... 相似文献