共查询到19条相似文献,搜索用时 125 毫秒
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以偏钛酸为原料,制备了锐钛矿型纳米TiO2中性水溶胶,采用XRD、SEM、TEM、吸收光谱以及光电流响应等对TiO2水溶胶进行表征.结果发现,TiO2粒径约为11.6 nm,稀土元素La掺杂,使得水溶胶的吸收光谱阙值红移至545 nm,可见光响应能力明显增强.光催化降解试验表明,溶胶对甲醛具有快速降解能力,当甲醛浓度≤3×10-6时,24 h可以降解至国家标准范围以内,但降解过程受环境湿度影响明显. 相似文献
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[目的]研究竹活性炭比表面积及其孔径对TiO2/BAC光催化降解甲醛性能的影响.[方法]以竹子为原料,按照不同浸渍比,用磷酸活化法制备不同孔径和比表面积的系列竹活性炭(BAC)作为载体;通过溶胶凝胶法制备负载型光催化剂(TiO2/BAC),以水溶液中的甲醛作为目标污染物,考察所得的一系列负载型光催化剂的光催化性能;采用氮气吸附、SEM 进行表征,研究了竹活性炭的孔径和比表面积对负载型光催化剂性能的影响.[结果]竹活性炭吸附和TiO2光解的协同效应使TiO2/BAC光催化剂对水溶液中甲醛的处理效率显著提高;比表面积较大、微孔较多、平均孔径为2~3 nm的竹活性炭有利于TiO2的负载,制备得到的复合光催化活性较高.[结论]为TiO2光催化剂的固化负载研究提供了理论依据. 相似文献
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采用溶胶-凝胶法制备混晶纳米TiO2和珍珠岩负载纳米TiO2混晶催化剂,以XRD、SEM、UV-vis DRS和电化学方法对样品进行表征.结果表明,晶型调节剂的含量对混晶中金红石和锐钛矿相TiO2的比率有较大的影响;对于负载型纳米TiO2催化剂,混晶比影响催化剂的光催化降解效率.并讨论了混晶的光催化机理. 相似文献
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光催化剂与建筑材料的结合是光催化领域一个重要的发展方向.文中以添加纳米TiO2的水泥为研究对象,以甲基橙的光催化降解活性为指标,考察了光催化水泥用量、水泥中TiO2的含量、水泥水化龄期以及甲基橙初始浓度对甲基橙降解效果的影响.结果表明,在紫外光照射下,当甲基橙的初始浓度为5 mg/L,光催化水泥用量为3 g/L,水泥中TiO2含量为5%时,光催化效率最高;延长水泥水化龄期,光催化水泥对甲基橙的吸附性能和降解性能均有所下降;提高甲基橙初始浓度,可以增强光催化水泥对甲基橙的吸附性能,当初始浓度达到15 mg/L时,光催化水泥的吸附量可达54.5%. 相似文献
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纳米TiO2改性内墙乳胶漆的抗菌性能及甲醛降解研究 总被引:3,自引:0,他引:3
为了制备具有空气净化和抑菌功能的环保型内墙涂料,在分析纳米TiO2的光催化原理,铈离子和银离子抑菌机理的基础上,采用锐钛型纳米TiO2载银载铈复合改性纯丙内墙乳胶漆,并对改性后的内墙涂料进行了定性的抑菌环试验、定量的抑菌率试验和甲醛降解试验研究。试验结果表明,纳米TiO2载银载铈复合改性后的内墙涂料具有优异的抗菌性能和甲醛降解能力,经24h后,改性内墙涂料的抑菌率达到99.9%以上,经过40WEt光灯照射8h后甲醛降解率达到75%。 相似文献
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利用溶胶-凝胶法在煅烧温度600 ℃制备了不同Y3 掺杂量的纳米TiO2粉体,并用XRD技术对样品进行了表征.研究了Y3 掺杂量对样品相结构、晶粒尺寸和光催化降解亚甲基蓝的活性的影响,利用相结构与纳米TiO2光催化活性关系探讨了Y3 掺杂对纳米TiO2的光催化活性.结果表明,适量掺杂Y3 可以提高其光催化活性.当Y3 掺杂量为0.04%, 纳米TiO2粉体的光催化活性最佳,降解率为94.6%,其金红石相含量为9.8%,平均粒径为12 nm,Y3 掺杂强烈地抑制TiO2由锐钛矿相向金红石相的转变,减小晶粒尺寸这两方面均有利于提高光催化活性. 相似文献
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基于正交设计与BP神经网络优化制备Cu-Ce/TiO_2的预测模型 总被引:1,自引:0,他引:1
采用过渡金属Cu和稀土金属Ce对TiO2进行改性。为获取高效的甲醛气体去除率,运用正交实验设计结合BP神经网络优化TiO2的改性方案。以Cu-Ce掺杂负载量、Cu-Ce摩尔比和烧结温度为正交实验设计因子,每个因子各取3个水平,以光催化甲醛气体的降解效率为目标因子,编制3因素4水平正交设计表。结合BP网络强大的函数拟合功能,以正交设计表中3因素为网络输入层,以光催化甲醛气体的降解效率为网络输出层,建立BP神经网络优化模型,并通过该模型进行预测和优选,得到最佳的活性炭改性方案。即Cu-Ce掺杂负载量为2.92%、Cu-Ce摩尔比为1∶1和烧结温度为517℃。此时光催化甲醛气体的降解效率为61.60%,与预测值59.47%的相对误差为3.46%。 相似文献
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采用溶胶-凝胶法和浸渍法制备了Gd3 掺杂TiO2光催化剂Gd/TiO2,以乙烯作为模拟污染物进行气相光催化降解实验,研究乙烯的流速、催化剂的粒径、热效应、反应温度等动力学因素对光催化降解反应的影响.结果表明,乙烯的流速≥20mL·min-1时,光催化活性趋于稳定;粒径大小对光催化活性基本上没有影响.乙烯在纯TiO2和Gd/TiO2样品上的光催化氧化是一级反应,光催化活性随着反应温度的升高而增强,其中,Gd/TiO2样品的光催化性能随反应温度的变化更显著.纯TiO2和Gd/TiO2样品的表观活化能分别为21.5 kJ·mol-1和16.3 kJ·mol-1,反应活化能降低,反应速率加快可能是纯TiO2掺杂Gd3 后光催化活性提高的动力学方面的原因. 相似文献
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锐钛矿型纳米TiO2溶胶的低温制备及其光催化活性评价 总被引:5,自引:0,他引:5
研究了以四氯化钛和氨水为原料,在常温下通过两步法制备TiO2溶胶。TEM和XRD分析表明,TiO2溶胶粒径小于10 nm,并存在一定数量的锐钛矿型晶相结构。自然光照条件下,通过对亚甲基蓝水溶液的光催化降解试验和对新鲜馒头的防霉试验,考察了TiO2溶胶的光催化活性,同时检验了TiO2溶胶的稳定性。结果表明,TiO2溶胶具有较好的光催化活性和稳定性。 相似文献
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《中国稀土学报(英文版)》2019,37(8):845-852
Gd~(3+)/TiO_2 and Gd_2O_3/TiO_2 nanoparticles were prepared by ball milling method.The effects of Gd~(3+)ion and Gd_2O_3 on the structure and optical property of TiO_2 were studied by XRD and UV-vis DRS.Specific surface area was determined by Brunauer-Emmett-Teller(BET)method.The morphology and elemental composition were characterized by SEM-EDS.XPS was used to determine the surface compositions and chemical character of elements.The sample sizes and microstructures were observed by TEM.The photocatalytic activities of TiO_2 nanoparticles modified with rare earth metal gadolinium(Gd~(3+)ion or Gd_2O_3)were evaluated by degradation of methylene blue(MB)under UV light.Experimental results indicate that 2,5 mol%Gd~(3+)/TiO_2 shows the best photocatalytic activity compared with Gd_2O_3/TiO_2 and pure TiO_2.The existence of gadolinium can exhibit the aggregation and induce lattice distortion of TiO_2 obtained from XRD,SEM and TEM results.The band gap energy of 2.5 mol%Gd~(3+)/TiO_2 decreases to3.07 eV and it leads to visible light absorption response which can be seen from UV-vis absorption spectra.The surface area of 2.5 mol%Gd~(3+)/TiO_2 equals to 85.8 m~2/g and average crystal size is 21.1 nm.EDS and XPS analyses reveal that gadolinium can be introduced either into TiO_2 lattice or adsorbed on the surface of TiO_2.The content of surface OH groups in 2.5 mol%Gd~(3+)/TiO_2 is 50,88%(1.55 times higher than that of pure TiO_2)and the content of lattice oxygen decreases to 11.26%.The MB(25 mg/L)degradation reaction rate constants of 2,5 mol%Gd~(3+)/TiO_2,0.5 mol%Gd_2O_3/TiO_2 and pure TiO_2 were0.0713,0.0588 and 0.0263 min~(-1),respectively.The degradation rates of rhodamine B(30 mg/L)in 60 min are 97,9%,90.1%and 84.6%for 2,5 mol%Gd~(3+)/TiO_2,0.5 mol%Gd_2O_3/TiO_2 and pure TiO_2,respectively. 相似文献
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《钢铁研究学报(英文版)》2015,(12)
The effect of TiO_2 addition to the stainless steel slag glass-ceramics was studied.Different mass percentages of TiO_2 were added to four samples of the parent glass made from stainless steel slag and cullet.The temperatures of nucleation and crystallization were determined by differential scanning calorimetry(DSC).According to Xray diffraction(XRD) and scanning electron microscopy(SEM) analysis,adding TiO_2 refined grains and restricted the formation of the akermanite phase by capturing Ca~(2+) to form the perovskite phase.Diopside was the main crystal phase of the glass-ceramics.The bending strength and Vickers hardness increased with the addition of TiO_2.The optimal amount of TiO_2 was 7 mass%,and the highest bending strength and Vickers hardness were 144.6 MPa and6.26 GPa,respectively. 相似文献
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Di Wu Chen Li Qiushi Kong Zaifeng Shi Dashuai Zhang Lili Wang Lizhi Han Xiaopeng Zhang Qiang Lin 《中国稀土学报(英文版)》2018,36(8):819-825
Ball milling method was applied to prepare Lu~(3+)/TiO_2 photocatalysts. The catalysts were characterized with X-ray powder diffraction(XRD), X-ray photoelectron spectroscopy(XPS), UV-visible diffuse reflectance spectra(UV-vis DRS), energy dispersive X-ray spectrometer(EDS), transmission electron microscopy(TEM) and Brunauer-Emmett-Teller(BET) method. The photocatalytic activities were determined by the degradation of methylene blue(MB) equipped with a 300 W medium pressure mercury lamp. Results show that the first order reaction rate constants of Lu~(3+)/TiO_2 and pure TiO_2 are0.0565 and 0.0263 min-1, respectively, which both were evaluated under the condition of catalysts loading of 0.2 g/L,initial concentration of 25 mg/L for MB, mole ratio of Lu~(3+)/TiO_2 of 1.5% and milling time of 4 h. The average crystal sizes of 1.5 mol% Lu~(3+)/TiO_2 and pure TiO_2 are 18.7 and 19.3 nm, respectively. 相似文献
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In this paper,various techniques including BET,XRD,SEM and XPS were used to study the sintering ofpure and La_2O_3-doped titania.The experimental results show that sintering of titania proceeds via volume diffu-sion.Adding of lanthanum oxide decreases the rate of sintering and hinders the phase transition from anatase torutile crystal by strong surface interaction between the mixed crystals(La_4Ti_9O_(24),La_(0.66)TiO_(2.99))and TiO_2. 相似文献