共查询到19条相似文献,搜索用时 187 毫秒
1.
采用溶胶凝胶法制备了不掺杂、V 掺杂、Ce掺杂、V/Ce共掺杂纳米TiO 2光催化剂,并将其分别负载于瓷砖上,利用X射线衍射分析(XRD)和扫描电镜分析(SEM)技术对薄膜样品的结构和形貌进行了表征。通过对甲醛的降解实验评价光催化剂的光催化活性。实验结果表明,光催化剂的负载量、共掺杂离子的掺杂量、掺杂配比、煅烧温度影响纳米TiO 2的光催化活性。V/Ce共掺杂TiO 2光催化剂产生了协同效应,其光催化活性优于纯TiO 2和单掺杂TiO 2样品。 相似文献
2.
以钛酸四丁酯为前驱体,过氧化氢为氧化剂,采用简单易行的低温氧化法制备出晶粒尺寸较小(平均尺寸25nm)的二氧化钛纳米粒子。通过贵金属Pt掺杂TiO2(Pt-TiO2)、稀土元素Ce掺杂TiO2(Ce-TiO2)和Pt、Ce共掺杂TiO2(Pt/Ce-TiO2)的掺杂的方法对二氧化钛进行改性。通过XRD,XPS,TEM,紫外漫反射等表征手段对制备的样品进行表征。通过可见光下降解罗丹明B来测试其光催化活性。实验结果表明,由ce掺杂的TiO2光催化剂对有机污染物的最大降解能力略大于Pt掺杂的TiO2,2种元素进行共同掺杂时对应的TiO2光催化剂降解能力最大。 相似文献
3.
模拟自然条件下的可见光,以甲醛的光催化降解为探针反应,评价了通过溶胶凝胶法分别制备的8种(银Ag、铜Cu、铁Fe、钨W、铈Ce、镧La、硫S、氯Cl)掺杂TiO 2纳米晶体的光催化活性及对甲醛水溶液的去除效果。用X射线衍射、激光粒度分析和紫外-可见分光光谱表征了掺杂纳米TiO 2的微晶尺寸、晶体结构与光学性能。结果表明:Ce离子尽管有较大的半径但是主要还是掺杂到晶格中,Ce掺杂可以促进TiO 2由非正分锐钛矿相向锐钛矿相和金红石相的转变,抑制载流子复合,使TiO 2的光吸收带边发生红移且有利于对可见光的吸收,从而使Ce掺杂TiO 2在模拟可见光下光催化甲醛水溶液的能力得到明显提高。 相似文献
4.
采用微乳法制备铁掺杂TiO 2纳米晶(Fe-TiO 2)复合体, 通过热重-差热(TG-DTA)、X射线衍射(XRD)、扫描电镜(SEM)和紫外漫反射光谱(DRS)等对其结构和形态进行表征; 以亚甲基蓝溶液(MB)为标准模拟降解物, 对Fe-TiO 2, 纯TiO 2和P25光催化降解性能进行评价。结果表明,Fe-TiO 2的光催化活性明显>P25,原因是Fe掺杂不仅能抑制TiO 2晶粒 相似文献
5.
以蒙皂石为载体,钛酸四丁酯为前驱物,在较低温度下由溶胶凝胶法制备得到负载型TiO 2光催化剂。研究了理论负载量、固定化温度、干燥、焙烧温度对TiO 2/蒙皂石复合光催化剂光催化性能的影响。采用XRD分析技术对复合材料进行了表征。结果表明,负载的TiO 2以锐钛矿-金红石的混晶相存在。当TiO 2理论负载量为15 mmol/g、溶胶反应温度为25℃、干燥温度为70℃时,TiO 2/蒙皂石复合光催化剂对偶氮染料光催化反应1 h降解率达93.40%。该制备技术的特点是在省去高温焙烧的条件下,制备出光催化活性高的负载型光催化剂。 相似文献
6.
以硫脲为硫的源物质,以钛酸四丁酯为TiO 2的前驱体,采用溶胶-凝胶法制备了掺硫改性TiO 2光催化剂。以活性艳红X-3B为目标污染物,研究了该催化剂的光催化降解性能,对硫掺杂量、催化剂焙烧温度、溶液pH值以及催化剂添加量等影响因素进行了研究,并采用XRD分析手法对光催化剂进行表征。结果表明,经掺硫改性后的TiO 2的催化活性有了很大提高,且硫的掺杂有一个最佳值,即Ti∶S的摩尔比为1∶1。经掺硫改性的TiO 2在可见光区具备一定的催化活性, 180 min内对活性艳红X-3B的去除率可达35.1%,且在紫外光区的催化活性优于纯TiO 2。 相似文献
7.
以钛酸四丁酯为前驱体,采用溶胶凝胶法,制备了CoO掺杂的TiO2光催化剂。利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、紫外可见漫反射(UV-vis DRS)对催化剂进行了分析、表征。以中压汞灯为光源,研究了亚甲基蓝(MB)在CoO/TiO 2微粒水悬浮液中的降解动力学。结果表明:所制备的催化剂活性组分主要是锐钛矿型的二氧化钛和CoO固溶体,粒径为25~30 nm,分布均匀。亚甲基蓝的光催化降解动力学满足一级动力学,在一定的浓度范围内,反应速率常数随初始浓度增大而减少,适当的掺钴量可以有效地提高TiO 2光催化活性,其最佳掺杂量重量百分比为0.25%。 相似文献
8.
溶胶-凝胶和浸渍相结合的方法制备锰掺杂WO 3-TiO 2复合光催化剂,RXD表征,考察WO 3和Mn 2+掺入量、焙烧温度、焙烧时间及催化剂用量对光催化降解甲基橙的影响。结果表明,500℃焙烧2h,掺杂量 n(Mn2+)∶ n(WO3)∶ n(TiO2)=0.8∶1∶100时,光催化活性最高,光催化降解甲基橙溶液,120min后,降解率达90%, 比单纯 TiO 2的光催化活性提高81%。 相似文献
9.
采用溶胶凝胶法制备了多壁碳纳米管负载纳米TiO 2的复合光催化剂(TiO 2/MWCNTs),以偶氮类染料甲基橙为目标污染物,在自制的光催化反应器上进行了光催化降解反应实验。主要研究同一甲基橙初始浓度( C0)下,多壁碳纳米管不同管长和管径对复合光催化剂催化效果的影响。结果表明:该降解反应可用一级反应动力学方程描述,反应速率常数k随着多壁碳纳米管管长和管径的增大而增大;与纯纳米TiO 2相比,复合光催化剂对甲基橙的降解率提高了6%~18%,反应速率常数为前者的1.19~2.11倍;采用复合光催化剂的甲基橙光降解溶液自行沉降分离效果较好,静止沉降60 min后达到沉降平衡,剩余浊度为8.5 NTU,下降了90.6%。 相似文献
10.
以钛酸四丁酯为原料,空心微珠为载体,采用溶胶凝胶法制备TiO 2/beads光催化剂载体,然后浸渍法制备出H 4SiW 12O 40/TiO 2/beads表面负载修饰型复合光催化剂,并运用SEM、XRD、FT-IR和DRS对催化剂进行表征和分析。研究了H 4SiW 12O 40/TiO 2/beads对亚甲基蓝降解的光催化活性,考察了光强度、pH值、曝气量、底物浓度和催化剂用量等对催化效率的影响。实验结果表明,在中性条件下,H 4SiW 12O 40/TiO 2/beads催化剂的投加量为0.25 g/L,浓度为7.5 mg/L的亚甲基蓝溶液在250 W的紫外灯和600 W的可见光灯下光照60 min降解率分别可达到94.5%和55%。 相似文献
11.
The ozone initiated oxidation of 1,3,7-trimethylxanthine (caffeine), commonly found in wastewaters as model compound is reported using cerium (Ce)/titanium dioxide (TiO 2) as catalyst. The effect of pH and loading of ceria on titania were investigated. Effect of reaction conditions on degradation of caffeine based on their pseudo first-order rate constants were compared. The combination of catalyst Ce-TiO 2 and ozone aeration significantly enhanced the degradation of caffeine compared to uncatalysed ozonation. The oxidation of caffeine ensued via the free radical mechanism, through enhanced ozone decomposition into OH radicals. Ce/TiO 2(0.5?wt%) showed good activity in degradation of caffeine at pH 6, in both natural stream and river water samples showing about 60% total organic carbon removal in 2?h ozonation period. Using liquid chromatography-mass spectroscopy, degradation products were analysed. A reaction intermediate and one final product were positively identified. Nano-catalysts with different loadings of Ce on TiO 2 synthesized by sol-gel route were characterized by scanning electron microscope, transmission electron microscopy, BET and powder X-ray diffraction spectrum techniques. The results showed that the material retained a highly ordered mesoporous structure and possessed large surface area. 相似文献
12.
This study investigates the mechanism of photosensitization and the recombination of excited electron–hole pairs affected by depositing platinum (Pt) on the surface of titanium dioxide (TiO 2). A new catalyst of Pt–TiO 2 was prepared by a photoreduction process. Being model reactions, the photocatalytic oxidation of methylene blue (MB) and methyl orange (MO) in aqueous solutions using the Pt–TiO 2 catalyst was carried out under either UV or visible light irradiation. The experimental results indicate that an optimal content of 0.75%Pt–TiO 2 achieves the best photocatalytic performance of MB and MO degradation and that the Pt–TiO 2 catalyst can be sensitized by visible light. The interaction of Pt and TiO 2 was investigated by means of UV–Vis absorption spectra, photoluminescence emission spectra, and X-ray photoelectron emission spectroscopy. The Pt 0, Pt 2+ and Pt 4+ species existing on the surface of Pt–TiO 2, and the Ti 3+ species existing in its lattice may form a defect energy level. The Pt impurities, including Pt, Pt(OH) 2, and PtO 2, and the defect energy level absorb visible light more efficiently in comparison with the pure TiO 2 and hinder the recombination rate of excited electron–hole pairs. 相似文献
13.
Nitrogen-doped titanium dioxide (TiO2) and Fe–N-codoped TiO2 layers on fly ash cenospheres (FAC) as floating photocatalyst were successfully prepared through sol–gel method. Photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet (UV)–Vis diffuse reflectance spectroscopy (DRS), and nitrogen adsorption analyses for Brunauer–Emmett–Teller (BET) specific surface area. Photocatalytic efficiency of the prepared catalyst was evaluated through using the decomposition of Rhodamine B (RhB) as a model compound under visible light irradiation. Photocatalytic activity and kinetics of catalyst under visible light were detected in details from different Fe/Ti mole ratios by detecting photodegradation of RhB. Experimental results show that when the calcination temperature was 550 °C, the dosage of FAC was 3.0 g, and the mole ratio of Fe/Ti was 0.71 %; the synthesized Fe–N-TiO2/FAC photocatalyst presented as anatase phase and that N and Fe ions were doped into TiO2 lattice. The material’s specific surface area was 34.027 m2/g, and UV–Vis diffuse reflectance spectroscopy shows that the edge of the photon absorption has been red shifted up to 400–500 nm. Fe–N-codoped titanium dioxide on FAC had excellent photocatalytic activity during the process of photodegradation of RhB under visible light irradiation. 相似文献
14.
This study reports the synthesis and characterization of composite nitrogen and fluorine co-doped titanium dioxide (NF-TiO 2) for the removal of contaminants of concern in wastewater under visible and solar light. Monodisperse anatase TiO 2 nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-TiO 2 by direct incorporation into the sol–gel or by the layer-by-layer technique. The composite films were characterized with X-ray diffraction, high-resolution transmission electron microscopy, environmental scanning electron microscopy, and porosimetry analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was evaluated in a synthetic water solution and in an effluent from a hybrid biological concentrator reactor (BCR). Minor aggregation and improved distribution of monodisperse titania particles was obtained with NF-TiO 2-monodisperse (10 and 50 nm) from the layer-by-layer technique than with NF-TiO 2?+?monodisperse TiO 2 (300 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-layer method achieved significantly higher degradation rates in contrast with NF-TiO 2-monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO 2-P25. Using NF-TiO 2 layer-by-layer with monodisperse TiO 2 (50 nm) under solar light irradiation, the respective degradation rates in synthetic water and BCR effluent were 14.6 and 9.5?×?10 ?3?min ?1 for caffeine, 12.5 and 9.0?×?10 ?3?min ?1 for carbamazepine, and 10.9 and 5.8?×?10 ?3?min ?1 for atrazine. These results suggest that the layer-by-layer technique is a promising method for the synthesis of composite TiO 2-based films compared to the direct addition of nanoparticles into the sol. 相似文献
15.
TiO 2:Nb nanopowders within a dopant concentration in the range of 0.1?C15?at.% were prepared by one-step flame spray synthesis. Effect of niobium doping on structural, optical and photocatalytic properties of titanium dioxide nanopowders was studied. Morphology and structure were investigated by means of Brunauer?CEmmett?CTeller isotherm, X-ray diffraction and transmission electron microscopy. Diffuse reflectance and the resulting band gap energy were determined by diffuse reflectance spectroscopy. Photocatalytic activity of the investigated nanopowders was revised for the photodecomposition of methylene blue (MB), methyl orange (MO) and 4-chlorophenol under UVA and VIS light irradiation. Commercial TiO 2-P25 nanopowder was used as a reference. The specific surface area of the powders was ranging from 42.9?m 2/g for TiO 2:0.1?at.% Nb to 90.0?m 2/g for TiO 2:15?at.% Nb. TiO 2:Nb particles were nanosized, spherically shaped and polycrystalline. Anatase was the predominant phase in all samples. The anatase-related transition was at 3.31?eV and rutile-related one at 3.14?eV. TiO 2:Nb nanopowders exhibited additional absorption in the visible range. In comparison to TiO 2-P25, improved photocatalytic activity of TiO 2:Nb was observed for the degradation of MB and MO under both UVA and VIS irradiation, where low doping level (Nb?<?1?at.%) was the most effective. Niobium doping affected structural, optical and photocatalytic properties of TiO 2. Low dopant level enhanced photocatalytic performance under UVA and VIS irradiation. Therefore, TiO 2:Nb (Nb?<?1?at.%) can be proposed as an efficient selective solar light photocatalyst. 相似文献
16.
This work aimed to optimize high-performance photocatalysts based on graphene oxide/titanium dioxide (GO/TiO 2) nanocomposites for the effective degradation of aqueous pollutants. The catalytic activity was tested against the degradation of dichloroacetic acid (DCA), a by-product of disinfection processes that is present in many industrial wastewaters and effluents. GO/TiO 2 photocatalysts were prepared using three different methods, hydrothermal, solvothermal, and mechanical, and varying the GO/TiO 2 ratio in the range of 1 to 10%. Several techniques were applied to characterize the catalysts, and better coupling of GO and TiO 2 was observed in the thermally synthesized composites. Although the results obtained for DCA degradation showed a coupled influence of the composite preparation method and its composition, promising results were obtained with the photocatalysts compared to the limited activity of conventional TiO 2. In the best case, corresponding to the composite synthesized via hydrothermal method with 5% of GO/TiO 2 weight ratio, an enhancement of 2.5 times of the photocatalytic degradation yield of DCA was obtained compared to bare TiO 2, thus opening more efficient ways to promote the application of photocatalytic remediation technologies. 相似文献
17.
In this work, Ag-doping TiO 2 nanotubes were prepared and employed as the photocatalyst for the degradation of toluene. The TiO 2 nanotube powder was produced by the rapid-breakdown potentiostatic anodization of Ti foil in chloride-containing electrolytes, and then doped with Ag through an incipient wetness impregnation method. The samples were characterized by scanning electron microscope, high-resolution transmission electron microscopy, X-ray diffraction, surface photovoltage measurements, X-ray photoelectron spectroscopy and N 2 adsorption. The nanotubular TiO 2 photocatalysts showed an outer diameter of approximately 40 nm, fine mesoporous structure and high specific surface area. The photocatalytic activity of Ag-doping TiO 2 nanotube powder was evaluated through photooxidation of gaseous toluene. The results indicated that the degradation efficiency of toluene could get 98% after 4 h reaction using the Ag-doping TiO 2 nanotubes as the photocatalyst under UV light illumination, which was higher than that of the pure TiO 2 nanotubes, Ag-doping P25 or P25. Benzaldehyde species could be observed during the photocatalytic oxidation monitored by in situ FTIR, and the formed benzaldehyde intermediate during reaction would be partially oxidized into CO 2 and H 2O. 相似文献
18.
用浸渍-提拉法制备玻璃弹簧负载型TiO2薄膜催化剂,在自制的反应器中进行光催化降解由丙酮、甲苯、对二甲苯组成的模拟室内挥发性有机污染物VOCs研究.研究发现:催化剂中掺杂金属离子能影响催化剂的降解效果,降解效果依次为掺铈TiO2>纯TiO2>掺银TiO2;气体流量显著影响降解效果,丙酮、甲苯和对二甲苯的最佳降解流量分别为3、5、7 L/min;混合气体中非对称性的极性分子的降解效率高于对称性分子,导致丙酮、对二甲苯组分降解率降低,甲苯降解率增高. 相似文献
19.
采用溶胶-凝胶法制备了不掺杂、V掺杂、Ce掺杂、V/Ce共掺杂纳米TiO2光催化剂,并将其分别负载于瓷砖上,利用X射线衍射分析(XRD)和扫描电镜分析(SEM)技术对薄膜样品的结构和形貌进行了表征。通过对甲醛的降解实验评价光催化剂的光催化活性。实验结果表明,光催化剂的负载量、共掺杂离子的掺杂量、掺杂配比、煅烧温度影响纳米TiO2的光催化活性。V/Ce共掺杂TiO2光催化剂产生了协同效应,其光催化活性优于纯TiO2和单掺杂TiO2样品。 相似文献
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