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采用溶胶-凝胶法制备了系列稀土(La、Eu、Nd、Tb、Er)和硫共掺杂TiO2光催化剂RE/S/TiO2。通过紫外-可见(UV-Vis)漫反射、X射线衍射(XRD)对催化剂进行了表征。以EDTA为电子给体,考察了光催化剂在可见光照射下的制氢活性。研究结果表明,S/TiO2具有可见光活性,稀土掺杂进一步提高了S/TiO2可见光活性,其活性顺序依次为Eu/S/TiO2>La/S/TiO2>Nd/S/TiO2>Tb/S/TiO2>Er/S/TiO2。与纯TiO2和S/TiO2光催化剂相比,稀土掺杂使催化剂的粒径减小,晶格畸变应力增大,从而提高了催化剂可见光制氢活性。 相似文献
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Qiao Zhang Ji-Bong Joo Zhenda Lu Michael Dahl Diana Q. L. Oliveira Miaomiao Ye Yadong Yin 《Nano Research》2011,4(1):103-114
Mesoporous nanocrystal clusters of anatase TiO2 with large surface area and enhanced photocatalytic activity have been successfully synthesized. The synthesis involves the
self-assembly of hydrophobic TiO2 nanocrystals into submicron clusters, coating of these clusters with a silica layer, thermal treatment to remove organic
ligands and improve the crystallinity of the clusters, and finally removing silica to expose the mesoporous catalysts. With
the help of the silica coating, the clusters not only maintain their small grain size but also keep their mesoporous structure
after calcination at high temperatures (with BET surface area as high as 277 m2/g). The etching of SiO2 also results in the clusters having high dispersity in water. We have been able to identify the optimal calcination temperature
to produce TiO2 nanocrystal clusters that possess both high crystallinity and large surface area, and therefore show excellent catalytic
efficiency in the decomposition of organic molecules under illumination by UV light. Convenient doping with nitrogen converts
these nanocrystal clusters into active photocatalysts in both visible light and natural sunlight. The strategy of forming
well-defined mesoporous clusters using nanocrystals promises a versatile and useful method for designing photocatalysts with
enhanced activity and stability. 相似文献
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A series of pure and Y3+-doped TiO2 nanoparticles with high photocatalytic activities were prepared by a sol-gel method using tetra-n-butyl titanate as precursor.The as-prepared catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and diffuse reflectance spectroscopy(DRS).The results indicated that yttrium doping could effectively reduce the crystalline size,inhibit the anatase-to-rutile phase transformation and surppress the recombination of the photogenerated electron-h... 相似文献
108.
以五水硝酸铋和五氧化二钒为原料,通过微波合成法制备了纳米BiVO4,采用X-射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征了样品的形貌、结构和特性。XRD表明所制备的样品是纯的单斜晶型BiVO4;SEM显示样品的形貌呈层状结构;TEM进一步指出这些片层结构是由小粒子聚集而成的多孔结构。以催化降解甲基橙来考察其光催化性能。在100mL的10mg/L甲基橙溶液中加入0.12g经673K恒温热处理2h后的BiVO4及0.2mL H2O2,调节pH值为3.0,在可见光下照射90min后,降解率达到94.70%,催化性能良好。 相似文献
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Marjo Kettunen Riitta J. Silvennoinen Nikolay Houbenov Antti Nykänen Janne Ruokolainen Jani Sainio Viljami Pore Marianna Kemell Mikael Ankerfors Tom Lindström Mikko Ritala Robin H. A. Ras Olli Ikkala 《Advanced functional materials》2011,21(3):510-517
Chemical vapor deposition of a thin titanium dioxide (TiO2) film on lightweight native nanocellulose aerogels offers a novel type of functional material that shows photoswitching between water‐superabsorbent and water‐repellent states. Cellulose nanofibrils (diameters in the range of 5–20 nm) with native crystalline internal structures are topical due to their attractive mechanical properties, and they have become relevant for applications due to the recent progress in the methods of their preparation. Highly porous, nanocellulose aerogels are here first formed by freeze‐drying from the corresponding aqueous gels. Well‐defined, nearly conformal TiO2 coatings with thicknesses of about 7 nm are prepared by chemical vapor deposition on the aerogel skeleton. Weighing shows that such TiO2‐coated aerogel specimens essentially do not absorb water upon immersion, which is also evidenced by a high contact angle for water of 140° on the surface. Upon UV illumination, they absorb water 16 times their own weight and show a vanishing contact angle on the surface, allowing them to be denoted as superabsorbents. Recovery of the original absorption and wetting properties occurs upon storage in the dark. That the cellulose nanofibrils spontaneously aggregate into porous sheets of different length scales during freeze‐drying is relevant: in the water‐repellent state they may stabilize air pockets, as evidenced by a high contact angle, in the superabsorbent state they facilitate rapid water‐spreading into the aerogel cavities by capillary effects. The TiO2‐coated nanocellulose aerogels also show photo‐oxidative decomposition, i.e., photocatalytic activity, which, in combination with the porous structure, is interesting for applications such as water purification. It is expected that the present dynamic, externally controlled, organic/inorganic aerogels will open technically relevant approaches for various applications. 相似文献
110.
采用了一种新颖而有效的方法制备SnO2纳米粒子:利用氩弧焊电弧形成的高温将反应台上的锡蒸发,在装置的另一端通过高压直流电场收集锡粒子,制得纳米级锡粒子,然后在空气气氛下将纳米锡粒子在800℃~90℃范围内进行热处理,最终得到SnO2纳米粒子。制得的SnO2纳米粒子粒径在50nm左右,且杂质较少。将制得的SnO2纳米粒子... 相似文献