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431.
Preparation of TiO2 Thin Film Photocatalysts by Dip Coating Using a Highly Viscous Solvent 总被引:6,自引:0,他引:6
TiO2 thin film photocatalysts coated onto soda lime glass were prepared by a dip coating process using a highly viscous solvent. The source of the TiO2 was tetraisopropyl orthotitanate, and -terpineol was used as the solvent. Two types of thin film preparation procedures based on dip coating (a sol-gel system and thermal decomposition system) were used to prepare the samples. TiO2 thin films were obtained after calcination at 450°C for 1 hour. The film thickness obtained with a single dipping was proportional to the viscosity of the dip coating solutions. The obtained thin films were transparent with a thickness of 1 m. The crystal form of the obtained photocatalyst films was anatase alone. The thin films were formed with aggregated nano-sized TiO2 single crystals (7–15 nm). The photocatalytic activity of the TiO2 thin films, as evaluated by the photooxidation of NO (1 ppm) in dry air, was as high as our previous TiO2 thin films prepared by the sol-gel method. 相似文献
432.
Cu/ZnO-TiO2复合半导体光催化材料的制备与表征 总被引:6,自引:0,他引:6
The metallic Cu modified n-p coupled semiconductors Cu/ZnO-TiO2 were prepared by sol-gel method, and their crystal structure, surface composition and absorptivity of UV light were investigated by techniques of DTA-TG, XRD, TEM, BET, TPR, IR and UV-Vis. The results show that the main crystal structure of the coupled-semiconductors is anatase TiO2 with the particle size in the range of 10~16 nm and BET surface area above 80 m2·g-1. In the process of Sol-gel the probability to form ZnO is reduced because of the dilution of Zn2+ with Ti(OC4H9)4. But through the molecular-level contact with TiO2, Zn2+ cations take the places of the O-tetrahedral and O-octahedral centers to partly form Zn2TiO4, and the coupling effects decrease the reflectivity of semiconductors in the wavelength region of 250~400 nm. A photo-exciting mechanism of the semiconductors embedded with metallic Cu was proposed. The Fermi energy of metallic Cu is in the band gap of ZnO and TiO2, so the addition of metallic Cu offers new energy bands to give and receive the photoelectrons, thus expanding the absorption region of the semiconductors to visible light. 相似文献
433.
The fungicide Flutriafol was mineralised on irradiation of its aqueous solution, in which anatase P25 was suspended, with a medium pressure mercury lamp under an air stream. The half-time of reaction, t1/2, i.e. the time at which the total organic carbon of the solution was halved, decreased in the series of P25 loaded with RuO2>Pt>Ag>MnO2. Heating P25 at 500°C for 3 h reduced t1/2 compared to bare, unheated P25. 相似文献
434.
Chien-Sheng Kuo Yao-Hsuan Tseng Chia-Hung Huang Yuan-Yao Li 《Journal of molecular catalysis. A, Chemical》2007,270(1-2):93-100
Ultraviolet and visible-light-responsive titania was synthesized and employed in the NOx photomineralization. A thermal decomposition reaction of titanium isopropoxide was carried out with a metal-organic chemical vapor deposition (MOCVD), enabling continuous production of TiO2 nanoparticles. Carbon-containing titanium dioxide with the anatase phase prepared at 500 °C under nitrogen atmosphere exhibited high photocatalytic activity for NO oxidation under visible-light illumination. Experimental results indicate that up to 48% removal of NOx can be achieved in a continuous flow type of reaction system under visible-light illumination (green LED). The chamber temperature in this MOCVD process plays an important role in lattice structure formation, and also affected TiO2 carbon content. The carbonaceous species on the TiO2 surface, shown by X-ray diffractometry (XRD), and Raman, UV–vis, and X-ray photoelectron spectroscopies (XPS), is important to the visible-light absorption and visible-light-catalytic mineralization of NOx. 相似文献
435.
层状纳米光催化复合材料HNbWO6/Pt的合成及性质 总被引:4,自引:0,他引:4
用固相合成法合成出LiNbWO6,并用离子交换法制备出HNbWO6;通过PrNH2 层间膨胀、Pt(NH3 ) 2 + 4层间插入和紫外光分解等反应 ,合成出一种新的层状光催化纳米复合材料HNbWO6/Pt ,并比较了不同合成方法对样品性能的影响 .X射线衍射、漫反射、ICP和比表面积测定等的表征结果表明 :该样品的层间高度为 0 .3~ 0 .5nm ,禁带能隙为 2 .2 5~ 3.10eV .用波长大于 2 90nm的 45 0W汞灯照射 5h ,1g样品可催化分解甲醇溶液 (10 % )产生氢气约 40ml,表明所研制的层状纳米复合材料具有较高的光催化活性 相似文献
436.
Modulating the properties of monolayer C_2N: A promising metal-free photocatalyst for water splitting 下载免费PDF全文
Photocatalytic water splitting has gained increasing attention, since it utilizes renewable resources, such as water and solar energy, to produce hydrogen. Using the first-principles density functional theory, we investigate the properties of the single layer C_2N which was successfully synthesized. We reveal that monolayer C_2N has a substantial direct band gap of 2.45 eV. To regulate its band gap, four different nonmetal elements(B, O, P, and S) on the cation and anion sites are considered. Among them, B-doped N site is the most effective one, with the lowest formation energy and a band gap of 2.01 eV. P-doped N site is the next, with a band gap of 2.08 eV, though its formation energy is higher. The band alignments with respect to the water redox levels show that, for these two dopings, the thermodynamic criterion for the overall water splitting is satisfied. We therefore predict that B-or P-doped C_2N, with an appropriate band gap and an optimal band-edge position, would be a promising photocatalyst for visible-light water splitting. 相似文献
437.
Structure-tuning strategies for synthesis and modification of Bi2MoO6, a novel visible light photocatalyst, have progressed at a quick pace. The enhancement of photocatalytic performances has been obtained through several morphology controls including hierarchical structures and heterojunctional nanocomposites. In this article, various structure modifications and their structural advantages in photocatalysis will be reviewed. In the first section, the structures of Bi2MoO6 such as crystal structures, electronic structures, and band structures will be presented. In the second section, many controllable synthesis approaches for modification of Bi2MoO6, including solid-state reaction, co-precipitation, solvothermal, and hydrothermal methods will be introduced. In the last section, the enhancement of photocatalytic activity for Bi2MoO6 due to the structure tuning will be discussed. The comprehensive review will provide perspectives on the research of efficient photocatalysts under visible light irradiation. 相似文献
438.
439.
440.
以ZnO及WO3为前驱反应物,制备了一系列不同ZnWO4含量的ZnWO4-ZnO复合光催化剂.利用X射线衍射、扫描电子显微镜及X射线能谱仪等手段对催化剂进行表征,并以紫外光为光源,罗丹明B为模拟污染物,评价催化剂的活性.结果表明,热处理温度及ZnWO4与ZnO摩尔比对催化剂光催化降解罗丹明B的活性影响显著.当复合4mol;ZnWO4,并于850 ℃煅烧所制得的ZnWO4-ZnO催化剂活性最高,比纯ZnO高出25;.这是因为ZnWO4的复合可抑制ZnO晶粒长大,提高光生电子与空穴的分离效率,进而改善其光催化活性. 相似文献