掺杂镧和铈的TiO2纳米粒子的结构相变

以钛酸四丁酯,La2O3和Ce(NO3)3@6H2O为原料,采用溶胶-凝胶法制备了纯的和分别掺杂5mol%镧和铈的TiO2纳米粒子,并利用XRD,TG-DTA,TEM和XPS等测试技术对样品的晶型、尺寸和形貌等进行了表征,主要考察了镧和铈的掺杂对TiO2的晶粒尺寸和锐钛矿→金红石结构相变的影响,并初步的探讨了镧和铈的作用机理.结果表明,600℃焙烧而获得的TiO2纳米粒子具有与P-25型TiO2粒子相类似的组成、结构、形貌和粒子尺寸;掺杂剂镧和铈分别以La2O3和CeO2小团簇形式存在,并比较均匀的弥散在TiO2纳米粒子中,二者的掺杂抑制了锐钛矿晶粒的增长和锐钛矿→金红石的结构相变,使相变温度显著提高,晶格畸变增大,而镧比铈的作用更加显著.镧和铈的作用机理可能主要与掺杂离子的半径和价态以及稀土氧化物的存在和熔点等有关.     

镧铈混合掺杂氧化钛纳米粉体晶型转变的研究

采用溶胶-凝胶法,在不同的热处理温度下制备了稀土镧铈掺杂的不同晶型的TiO2纳米粉体。用X射线衍射仪,透射电子显微镜对所制备的TiO2纳米粉体进行表征,分析在不同热处理温度下制备的TiO2纳米粉体的晶粒尺寸及晶相组成,研究热处理温度对晶型转变的影响。研究表明:与未掺杂的TiO2晶型转变温度650℃相比较,稀土镧铈混合掺杂大大的抑制了TiO2锐钛矿向金红石晶相的转变,且在800℃煅烧温度以下,平均晶粒在15nm之内;当达到晶相转变温度时,晶粒突增到49nm。     

TiO2-SnO2纳米粉末的制备及表征

以廉价的无机盐为原料,采用溶胶-凝胶(Sol-Ge l)法制备了TiO2-SnO2纳米粉,并采用DTA、XRD、TEM技术对粉体进行了表征.实验结果表明:用该法制得的TiO2-SnO2超细粉体粒径在5～7 nm左右.     

镧、铈掺杂TiO_2超滤膜的制备

考察了镧、铈掺杂对二氧化钛(TiO2)超滤膜的影响。镧掺杂可以有效抑制TiO2晶型随烧结温度增加的急剧转变。镧、铈掺杂可以有效控制膜层的粒径和孔径,并提高其抗酸碱性能。TiO2膜层粒径为60~80nm,孔径为10~60nm,抗酸碱性能较差;而经镧、铈掺杂后的TiO2膜层粒径为50nm左右,孔径为10~20nm,抗酸碱性能较好,其中镧掺杂效果优于铈掺杂。     

稀土元素掺杂纳米TiO2Zeta电位的研穷

采用溶胶-凝胶法制备纳米TiO2以及稀土元素（Ce、Nd、Pr、Sm）掺杂纳米TiO2粉体．采用透射电镜（TEM）表征粉体形貌，MARVEN NANO ZS-90仪器测试粉体Zeta电位。结果表明：制备粉体属于纳米级别；在pH值2～11范围内，Pr、Sm、Nd掺杂与纯纳米TiO2 Zeta电位-pH曲线形状大致相同，相对于纳米TiO2的Zeta电位-pH曲线，Pr、Sm掺杂曲线右移，等电点增大；Nd掺杂曲线左移，等电点减小。Ce掺杂未出现等电点，在pH值2～11范围内，其Zeta电位始终为负值，在pH值相同时，5％Ce-TiO2 Zeta电位绝对值〉1％Ce-TiO2、2．5％Ce-TiO2．     

稀土铈掺杂对纳米TiO2结构和性能影响

研究了纳米二氧化钛负载稀土铈离子的基本性能,二氧化钛对铈离子的吸附机理,焙烧温度对二氧化钛晶型结构影响,不同吸附量对二氧化钛光学性能的影响;结果表明纳米级二氧化钛对铈离子具有很强的吸附力,铈离子的添加提高了二氧化钛晶型转变温度,铈离子的吸附可以提高二氧化钛的光催化降解性能。     

稀土铈掺杂纳米ZnO抗菌复合材料研究

采用纳米ZnO为载体,按照不同掺杂比例制备了复合无机抗菌剂 Ce4 /ZnO,采用抑菌圈实验和最小抑菌浓度实验来检测其抗菌性能。结果表明,掺杂稀土Ce4 明显提高了纳米 ZnO的抗菌性。通过对ZnO白样和Ce4 /ZnO试样的XRD测试, 结果表明 Ce4 已进入 ZnO晶格,同时对复合抗菌机理进行了探索研究。     

镧铁掺杂的纳米TiO2薄膜的光吸收性能研究

采用溶胶-凝胶法,以钛酸四丁酯为原料,在生物载波片上制备了金属离子镧铁双元掺杂纳米TiO2薄膜,经过440℃高温热处理后,TiO2为锐钛矿型;通过紫外可见分光光度计测量薄膜的透射光谱,发现掺杂后TiO2的吸收边有改变,薄膜对可见光的吸收也明显加强.     

W掺杂纳米TiO2的制备及光催化性能

本文以钛酸丁酯Ti（OC4H9）4和钨酸铵（NH4）6W7O24·6H2O为原料,制备W掺杂的TiO2纳米粒子,用XRD、TEM和IR进行表征,以罗丹明B的光催化降解对其光催化性能进行了研究,表明掺杂使TiO2纳米粒子的光催化活性显著增强。     

纳米TiO2稀土元素掺杂改性与光催化性能研究

采用溶胶-凝胶法制备纳米材料,以钛酸丁酯为前驱体,冰醋酸为螯合剂,通过水解缩聚作用制备纳米TiO2,掺杂稀土元素Ce对纳米TiO2进行改性,运用热分析(DSC)、X射线衍射(XRD)、透射电镜(TEM)和光吸收等手段,研究了不同掺杂量对TiO2相变和光催化活性的影响,确定了最佳的掺杂量和热处理温度。     

Fabrication of the CN co-doped rod-like TiO2 photocatalyst with visible-light responsive photocatalytic activity

The CN co-doped TiO₂ nanorods were synthesized by the vapor transport method of water molecules, and urea was used as the carbon and nitrogen source. The samples were characterized by X-ray diffraction and photoelectron spectroscopy analysis. The scanning electron microscope images showed that as-prepared TiO₂ powders were nanorods, which were formed by the stacking of nanoparticles with a uniform size around 40 nm. The degradation of methylene blue with the prepared nanorods demonstrated the photocatalytic activities of TiO₂ under visible light are improved by doping with C and N elements. The main reasons were discussed: doping with C and N elements could enhance the corresponding visible-light absorption of TiO₂. On the other hand, doping C and N could create more oxygen vacancies in the TiO₂ crystals, which could capture the photogenerated electrons more effectively. Thus, more photogenerated holes could be left to improve the photocatalytic activity of TiO₂.     

钛酸锶铅纳米陶瓷粉的制备及其烧结致密化行为

采用化学共沉淀法制备了一系列(Sr1-xPbx)TiO3陶瓷粉体,通过差热-热重(DTA-TG)分析确定了共沉淀产物的煅烧温度.X射线衍射(XRD)分析表明,化学共沉淀产物基本上呈非晶态,随后煅烧过程中发生晶化,主晶相为立方(Sr1-xPbx)TiO3固溶体.随着Pb含量的增加,逐渐出现游离的四方PbTiO3次晶相.所制得的(Sr1-xPbx)TiO3粉体具有纳米晶粒及纳米颗粒结构,平均晶粒及颗粒尺寸分别为20～30 nm和20～50 nm;颗粒形貌为不规则球形,团聚较为严重,以一次团聚颗粒为主,平均直径为200 nm,较大的二次团聚体平均粒径约为750 nm.纳米粉体烧结成瓷的温度显著降低,在1 150℃烧结基本实现致密化,而且由烧结前的立方相为主完全转变为四方相,没有了游离的PbTiO3并存在铁电畴亚结构.     

纳米二氧化钛粉体水基体系分散稳定性评价研究

以乙二醇为分散剂，设计了正交实验考察纳米二氧化钛粉体在水中的分散性能，采用重力沉降法、分光光度法、粘度法、Zeta电位测定法、粒径分析等方法评价其分散效果。比较不同的表征手段的优劣及其适用的条件，寻求一种科学、准确、简易的表征二氧化钛粉体分散稳定性的方法。实验结果表明，分光光度法操作简便，对实验仪器要求不高，能快速表征体系的分散稳定性：结合Zeta电位测定和粒径分析，可以得到纳米二氧化钛分散稳定性的可靠信息。最后提出了纳米粉体分散研究的一般方法。     

Au-N共掺杂TiO2纳米管电极的制备与表征

采用等离子体法和光化学沉积法制备出Au-N共掺杂TiO2纳米管(Au-N-TNT)电极,并对其进行了扫描电镜(SEM)、X射线衍射(XRD)、紫外可见漫反射(UV-VIS-DRS)、循环伏安(CV)、和瞬态光电流(I-t)分析.以Au-N-TNT为工作电极,对四环素进行了光电催化降解研究.结果表明,Au-N-TNT管口...     

Er-Ce共掺杂TiO2纳米粉体的制备及光催化性能研究

采用溶胶-凝胶法制备了Er-Ce共掺杂的TiO2纳米粉体，并以亚甲基蓝溶液为目标降解物研究了掺杂纳米TiO2粉体在紫外光作用下的光吸收和光催化性能。采用TG-DTA、XRD和TEM等测试技术对样品的晶型、形貌和粒径尺寸进行了表征。结果表明，Er-Ce共掺杂的TiO2粉体最佳热处理温度为550℃，结晶完整、主晶相为锐钛矿型，平均粒径约为20nm；掺杂可使TiO2吸收带发生红移，光催化性能增强；共掺杂体系的最佳量为n（Er）：n（TiO2）=0．1％，n（Ce）：n（TiO2）=0．05％。此掺杂量的TiO2粉体对亚甲基蓝有良好的降解效果，反应2h降解效果达到92．37％，优于同等条件下制备的未掺杂的纯TiO2粉体。掺杂复合光催化剂对亚甲基蓝的降解遵循一级动力学方程。     

Preparation and properties of sliver and nitrogen co-doped TiO2 photocatalyst

TiO₂ photocatalysts co-doped with different content of Ag and N were prepared by sol–gel method combined with microwave chemical method. The samples were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), ultraviolet–visible diffuse reflectance spectrum (UV–vis) and photo-luminescence emission spectrum (PL). The photocatalytic activity was investigated by photocatalytic degradation of methylene blue (MB) under irradiation of fluorescent lamp. The results indicate that Ag and N co-doping can restrain the increase of grain size, broaden the absorption spectrum to visible light region, and inhibit the recombination of the photo-generated electron–hole pairs. Moreover, the photocatalytic activity of Ag–N–TiO₂ in MB degradation is remarkable improved. The degradation rate of the sample with Ag:TiO₂ = 0.05 at%, N:TiO₂ = 18.50 wt% in 5 h is 93.44%, which is much higher than that of Degussa P25 (39.40%).     

复合TiO2纳米管制备与表征

首次采用温和的制备方法制得Al2O3-TiO2纳米管.TiO2粉体在700℃下熔融、110℃水热反 应,制备了管径约为数纳米、单层管壁厚约为0.2纳米,管长约为数微米的复合Al2O3-TiO2纳米管.组织形貌和特性使用TEM、DRS和XRD进行表征.由于Al2O3的沉积在TiO2纳米管上,导致纳米管对紫外光的吸收蓝移40 nm.并对其形成机理进行了讨论.     

TiO2 nanoparticles co-doped with silver and nitrogen for antibacterial application

We have prepared a series of TiO2 nanoparticles for antibacterial applications. These TiO2 nanoparticles were prepared by the hydrolysis precipitation method with Ti(OBu)4, silver nitrate and ammonia. Crystal structure, particle size, interfacial structure and UV-visible light response of the prepared nanoparticles were characterized by X-ray diffraction measurements (XRD), Transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR) and UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRs). The XRD spectra showed that all samples were anatase structure calcined at 450 degrees C for 3 hours. The Ag doping made the peak of diffraction wider. The results of TEM showed that the nanoparticles of TiO2, N-TiO2 and 1% Ag-N-TiO2 were all spherical in shape and well distributed with a mean size of 19.8 nm, 39.2 nm and 20.7 nm, respectively. N doping caused the nanoparticle size to increase, while, when the doped amount of Ag+ increased, the TiO2 particle size decreased. The FTIR revealed that Ag and N doping of TiO2 appeared to have strong absorption by -OH group and showed the characteristic absorption band of NH4+ and Ag. The UV-Vis-DRs indicated that the absorption band of Ag-N co-doped TiO2 had red shift and that the optical absorption response (between 400 nm and 700 nm) had obvious enhancement. The antibacterial properties of nanoparticles were investigated by agar diffusion method toward Escherichia coli and Bacillus subtilis. The results indicated that both Ag- and N-doped TiO2 could increase the antibacterial properties of TiO2 nanoparticles under fluorescent light irradiation. A 1% Ag-N-TiO2 had the highest antibacterial activity with a clear antibacterial circle of 33.0 mm toward Escherichia coli and 22.8 mm toward Bacillus subtilis after cultivation for 24 hours.     

Fabrication and microstructure of TiO2--ZrO2 composite membranes

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