掺锌的TiO2纳米粉的结构相变及发光性质

采用溶胶－凝胶法制备了掺锌的TiO     

中温制备CeO2—TiO2复合氧化物及其结构研究

采用sol-gel法在700℃制备出氧化物陶瓷法1300℃才能获得的CeTi2O6复合氧化物.XRD结构分析表明,其晶体结构中存在8%的Ce缺位,化学式为Ce0.92Ti2O5.84,单斜晶系,空间群C2/m,晶胞参数a=0.9811(8)nm,b=0.3726(3)nm,c=0.6831(6)nm,β=118.84°.在1300℃焙烧该复合氧化物,晶系不变,缺位消失,化学式转变为正常的CeTi2O6,晶胞参数a=0.9813(3)nm,b=0.3752(4)nm,c=0.6883(5)nm,β=119.05°.用sol-gel法制备CeTi2O6复合氧化物先驱物,     

掺硼纳米TiO2的制备及光催化性能研究

采用改进的Sol-gel方法,制备了单分散椭球形微孔结构的掺B纳米TiO₂光催化剂,并用TG-DTA、XRD、XPS、UV-Vis、TEM、BET等手段进行表征.以难生化降解的染料罗丹明B为目标降解物,采用HPLC检测,通过不同光照时间下染料降解率考察了产物的光催化活性.结果表明,改进的Sol-gel法制得的光催化剂具有明显的孔结构,而且比表面积大、孔径分布窄、粒径小、分散性好;适量B的掺杂能够有效促进TiO₂纳米粒子的光催化活性.最佳催化剂制备条件:B掺杂的摩尔分数为20%、450℃煅烧2 h,此时所制得的B-TiO₂光催化剂活性比纯TiO₂有显著提高.     

热处理对TiO2纳米管结构相变的影响

TiO₂纳米管为无定形结构,焙烧后则由无定形转变为锐钛矿型,纳米管的管状结构被破坏,晶型转变是TiO₂纳米管的管状结构破坏的根本原因.经热处理,原来的TiO₂纳米管部分转变为长棒状的金红石型晶柱结构,而原料TiO₂在较大温度范围内焙烧均未出现长棒状晶柱结构;TiO₂由A→R的相变温差很大,TiO₂纳米管的A→R相变温度比原料约低350℃;合成的TiO₂纳米管的比表面积和孔体积很大.     

掺Sn的纳米TiO2表面光致电荷分离及光催化活性

采用溶胶-凝胶法制备了不同掺Sn量的TiO₂纳米粒子, 主要利用表面光电压谱(SPS)和光致发光光谱(PL)对样品进行了表征, 并通过光催化降解苯酚实验来评估样品活性. 重点考察了热处理温度和掺Sn量对样品表面光生载流子的分离及光催化活性的影响, 并探讨了Sn使TiO₂纳米粒子改性的机制. 结果表明, 在适当温度处理下, 适量Sn的掺入能够有效促进TiO₂纳米粒子表面光生载流子的分离, 以至于使其光催化活性得到显著提高.     

溶胶-凝胶法制备掺Sm3+的SiO2玻璃的结构及发光性能

利用溶胶-凝胶技术制备了掺不同量Sm3+和不同退火温度下的SiO2凝胶和玻璃,通过三维荧光光谱、激发光谱、发射光谱的测试,确定了Sm3+在SiO2凝胶玻璃中的最佳激发波长为360 nm,最强发射波长为610 nm,激发光谱的峰位置在360、393、464 nm处,发射光谱的峰位置在578、591、595、610、732nm处,分别归属于4G5/2-6H5/2、4G5/2-6H7/2、4G5/2-6H11/2跃迁,并证明当掺杂量达到1.15%时,Sm3+的发光最强,当Sm3+的掺杂量超过1.15%时,发生浓度猝灭效应.     

掺锗SiO2 玻璃的发光现象

掺锗SiO2 玻璃的发光现象;Ge/SiO2玻璃;Ge纳米晶粒;溶胶-凝胶;光致发光     

掺Tb-硅基发光材料制备过程中结构及发光性能

采用溶胶-凝胶技术 ,制备了不同退火温度下掺 Tb3＋的 SiO2玻璃 ,掺 Tb3＋的凝胶玻璃在 448,544,585,620 nm显示 Tb3＋的 5D4- 7FJ(J=3,4,5,6)的特征发光光谱 .通过不同退火温度下样品的激发光谱、发射光谱、红外光谱、远红外光谱及差热-热重谱研究了掺 Tb3＋的硅基材料由凝胶向玻璃转变过程中的结构变化及对 Tb3＋发光性能的影响 .结果显示 ,在 50～ 100℃退火温度下 ,凝胶大部分吸附水分子被除去 ,在 150～ 500℃退火温度区 ,是凝胶向玻璃转变的主要结构变化区 ,并且其发光强度也明显增加 ,到 800℃时趋于稳定 .这些现象得出一个结论 ,Tb3＋的发光跃迁被 O－ H基强烈猝灭而随退火温度的升高而加强 .     

掺铕Y2O3发光薄膜的制备及发光性能

溶胶-凝胶法;荧光;掺铕Y2O3发光薄膜的制备及发光性能     

掺Tb-硅基发光材料制备过程中结构及发光性能

采用溶胶 凝胶技术,制备了不同退火温度下掺Tb3＋的SiO2玻璃,掺Tb3＋的凝胶玻璃在448,544,585,620 nm显示Tb3＋的5D4 7FJ(J=3,4,5,6)的特征发光光谱.通过不同退火温度下样品的激发光谱、发射光谱、红外光谱、远红外光谱及差热 热重谱研究了掺Tb3＋的硅基材料由凝胶向玻璃转变过程中的结构变化及对Tb3＋发光性能的影响.结果显示,在50～100 ℃退火温度下,凝胶大部分吸附水分子被除去,在150～500 ℃退火温度区,是凝胶向玻璃转变的主要结构变化区,并且其发光强度也明显增加,到800 ℃时趋于稳定.这些现象得出一个结论,Tb3＋的发光跃迁被O－H基强烈猝灭而随退火温度的升高而加强.     

铁酸锌掺杂对二氧化钛结构相变及光催化性能的影响

分别采用共沉淀法和溶胶-凝胶法制备铁酸锌和二氧化钛纳米粉体,较系统地研究了铁酸锌纳米掺杂对二氧化钛“锐钛矿→金红石”的结构相变及光催化性能的影响.结果表明,适量铁酸锌的掺杂可促进二氧化钛的结构相变,显著提高其光催化活性,在最佳掺杂浓度时,其光催化降解苯酚的效率可以提高2～3倍.     

One-pot easily-processed TiO2 macroporous photoanodes (Ti-HIPE) for dye-sensitized solar cells

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Photoluminescence Properties of Quinidine and Quinidine Sulfate in the Sol‐gel System

The emission spectra of quinidine and quinidine sulfate doped in sol‐gels (tetraethoxysiliane system) have been measured during the sol‐gel transformation. Shifts in the emission spectra from 370 nm to 435 nm were observed in both molecules as the system changed from sol stage to dried glass over a period of two weeks. These shifts are attributed to the conformational changes of the doped molecules. In addition, the process of the signal changes was observed by an emerging new band at ?435 nm with a concomitant decline of the original band at 370 nm during the sol‐gel transformation. These results indicate that the conformational changes induced by the sol‐gel transformation are accomplished in one step instead of several intermediate states.     

Phase Transformation Strategies for the Construction of Heterojunction TiO2 Photocatalysts

Heterojunction TiO₂ has attracted great attention in photocatalytic applications due to its high efficiency in the separation of photogenerated electron-hole pairs and strong ability of light absorption. This work concisely summarizes the distinct crystal phases of TiO₂ and elucidates the prevalent methods employed in the synthesis of TiO₂ heterojunctions. Furthermore, the review highlights novel strategies for the realization of TiO₂ phase transformation, thereby contributing to a deeper understanding and advancement in the application of mixed-phase TiO₂ photocatalysts.     

CoFe2O4纳米粉体的聚丙烯酰胺凝胶法合成、表征及磁特性

采用改进的聚丙烯酰胺凝胶法制备了CoFe2O4纳米粉体.利用TG-DSC、mR及XRD等多种手段研究了干凝胶的热分解及CoFe2O4的成相过程.实验表明,以EDTA为配位剂,在500℃的烧结温度下可制备出高纯的CoFe2O4纳米粉体.同时发现.通过改变双丙烯酰胺与丙烯酰胺的比例,可以调控粉体的晶粒尺寸;随着双丙烯酰胺比...     

低温液相制备金红石型TiO2纳米晶须

目前，已有多种控制TiO2形貌及晶须生长的方法，如模板合成、超分子组装、声化学合成液相法及固相合成等，其中，液相法是最为廉价和简单的方法．为此，近期采用低温液相法合成金红石型TiO2受到了极大的关注．本文在以前工作的基础上，采用改进的实验方法通过在低温陈化一定浓度的TiCl4水溶液直接获得了金红石型TiO2纳米晶须，并对产物进行了初步表征．     

Photoluminescence of samarium-doped TiO2 nanotubes

Samarium (Sm)-modified TiO₂ nanotubes (TNTs) were synthesized by low-temperature soft chemical processing. X-ray powder diffraction analyses of the synthesized Sm-doped and non-doped TNTs show a broad peak near 2θ=10°, which is typical of TNTs. The binding energy of Sm ³d_5/2 for 10 mol% Sm-doped TNT (1088.3 eV) was chemically shifted from that of Sm₂O₃ (1087.5 eV), showing that Sm existed in the TiO₂ lattice. Sm-doped TNTs clearly exhibited red fluorescence, corresponding to the doped Sm³⁺ ion in the TNT lattice. The Sm-doped TNT excitation spectrum exhibited a broad curve, which was similar to the UV–vis optical absorption spectrum. Thus, it was considered that the photoluminescence emission of Sm³⁺-doped TNT with UV-light irradiation was caused by the energy transfer from the TNT matrix via the band-to-band excitation of TiO₂ to the Sm³⁺ ion.     

Zn_2SnO_4纳米材料制备及光致发光特性

以ZnO、SnO2和活性炭的混合物为原料,通过碳热还原热蒸发法无催化剂成功制备出Zn2SnO4纳米材料.借助X射线衍射仪(XRD)、拉曼光谱和扫描电子显微镜(SEM)对样品物相和形貌进行了表征,结果显示样品为面心立方结构的Zn2SnO4纳米链状棒,同时含有少量的ZnO物相.利用X射线光电子能谱(XPS)对Zn2SnO4样品表面各元素的化学状态及相互作用方式进行了测试,结果表明:样品中Zn和Sn分别是以+2价和+4价氧化态形式存在,其中Zn2p3/2电子有两个结合能,分别来自ZnO和Zn2SnO4,Zn2SnO4中Sn4+占据不同的格点位置.室温下光致发光谱(PL)结果显示,样品在紫外区域(320-450nm)和可见区域存在很强的发光带,其中紫外区域的宽发光带,经过高斯拟合可分为358和385nm两个发光峰,与同条件下制备得到的纯ZnO纳米材料发光谱比较,确认358nm发光峰是来自于Zn2SnO4的近带边复合发光.     

Photoluminescence and photoactivity of titania particles prepared by the sol–gel technique: effect of calcination temperature

The photoluminescence (PL) characteristics of anatase titania particles prepared by the sol–gel method were investigated and correlated to their photocatalytic behavior with respect to the change of calcination temperature. It was found that the photoluminescence intensity measured at 77 K was gradually increased by increasing the calcination temperature due to the reduction of the internal defects which are responsible for the radiationless recombination of photoexcited electron/hole pairs. Also, the calcination temperature was found to influence the maximum peak position (λ) of the photoluminescence spectra of titania. That is, a blue shift of the photoluminescence spectrum occurs as a consequence of the enlargement of the energy-gap between the lowest excited state and the ground state of titania as increasing the calcination temperature. The quenching behavior of the photoluminescence at 77 K was monitored by in situ supplying oxygen at 77 K in order to investigate what happened to the surface of titania by the calcination. The quenching intensity was monotonically increased with increasing the calcinations temperature. Based on the above results, we concluded that the calcination of titania at higher temperature produces more surface-active sites easily reacting with oxygen molecules as well as improving the crystallinity of anatase phase. Consequently, higher temperature heat treatment of anatase titania particles makes it possible to get higher photoactivity as long as no significant rutile phase is formed.