Studies on Photocatalytic Activity of Powders and Hydrophilicity Property of Thin Films of TiO2 Codoped with Iron and Nitrogen

TiO2在光催化反应中具有高强度的氧化能力，能够将大多数有机污染物最终降解成为CO2、H2O以及其它无机小分子物质，从而消除对环境的污染。进一步对TiO2薄膜表面结构进行研究，研究者还观察到TiO2的另一特性——光致超亲水性。由于TiO2的带隙能较大（Eg=3.2eV），只有在紫外光照射下才能表现出高光催化活性和超亲水性。但是紫外光在太阳光中所占比例较小，使得太阳光能的利用率很低。此外，光生电子与空穴的高复合几率还会降低光量子产率。这些不利因素均使TiO2材料的实际应用受到限制。考虑到以上因素，本研究使用铁、氮共掺杂TiO2，对其进行改性研究，以期使TiO2的吸收波长向可见光方向移动，并使Ti...TiO2 photocatalytic oxidation is a promising method of sewage treatment and air purification, which, by virtue of its strong oxidation power, can decompose most organic pollutants into CO2, H2O and other small inorganic molecules completely. By research on surface structure of TiO2 thin films, it had been found that ultraviolet (UV) illumination of TiO2 could create a hydrophilic surface that allo...学位：理学硕士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：20042507

Hydrophilicity of TiO_2 Thin Films Codoped with Iron and Nitrogen

[中文文摘]采用溶胶-凝胶法制备了铁掺杂TiO2(Fe-TiO2)薄膜,将Fe-TiO2薄膜放置氨气气氛中高温处理,形成铁、氮共掺杂TiO2(Fe/N-TiO2)薄膜.通过XRD、XPS、SEM、UV-Vis法进行吸收光谱分析及薄膜表面亲水接触角分析,研究了铁、氮掺杂浓度,热处理温度,膜厚等因素对薄膜亲水性能的影响.结果表明,Fe/N-TiO2(0.5%Fe,摩尔百分数)显示出更佳的亲水性能,在可见光下优势尤为明显.铁掺杂主要作用是降低电子和空(的复合几率,氮掺杂可以增强TiO2薄膜在可见光区的吸收,两种效应相互结合,共同提高了薄膜在可见光下的亲水性能.[英文文摘]TiO2 doped with iron(Fe-TiO2)thin films were synthesized using sol-gel method.TiO2 codoped with iron and nitrogen(Fe/N-TiO2)thin films were prepared by calcining Fe-TiO2 thin films in ammonia atmosphere.The influence of iron and nitrogen doping concentration,heat-treatment temperature and film thickness on the hydrophilicity of the films were studied by XRD,XPS,SEM,UV-Vis spectra and measured water contact angle.The results indicated that Fe/N-TiO2(0.5%Fe,molar percent)films were optimum in hydrophilicity,especially under visible-light irradiation. Doping iron mostly reduced the recombination of electrons and holes, and doping nitrogen in TiO2 enhances photoresponse in visible-light region. The hydrophilicity benefited from both effects.国家自然科学基金(50472057

Preparation and Photocatalytic Activity of TiO_2 Powder Codoped with Iron and Nitrogen

Using TiCl4 as the titanium source, nanoparticles of TiO2 doped with nitrogen(N-TiO2) were synthesized by triethylamine. TiO2 powder codoped with iron and nitrogen(Fe/N-TiO2) were prepared by adsorption-deposition of Fe3+ on N-TiO2 and calcining at 400 ℃ for 2 h. From the XPS results for N1s binding energy at 399.6 eV and 396.6 eV, it is proposed that the partial N atoms as substitution atoms replace for O atoms in TiO2 lattice. The onset of the absorption spectrum of Fe/N-TiO2 has a 45 nm red-shift compared with that of TiO2. The results of photocatalytic degradation of methylene blue solution indicate that Fe/N-TiO2 (0.45% Fe3+) has a higher activity.Its photocatalytic activity is about 2 times as high as that of pure TiO2 under UV-light, and 3 times under sunlight. Doping of nitrogen in TiO2 enhances photoresponse in visible light region and doping of Fe3+ reduces the recombination of electrons and holes. Both of the above effects are beneficial for improving the performances of Fe/N-TiO2 photocatalyst.国家自然科学基金(No.50472057

Preparation and photocatalytic activity of TiO2 powder codoped with iron and nitrogen

Using TiCl4 as the titanium source, nanoparticles of TiO2 doped with nitrogen (N-TiO2) were synthesized by triethylamine. TiO2 powder codoped with iron and nitrogen (Fe/N-TiO2) were prepared by adsorption-deposition of Fe3+ on N-TiO2 and calcining at 400 degrees C for 2 h. From the XPS results for N1s binding energy at 399.6 eV and 396.6 eV, it is proposed that the partial N atoms as substitution atoms replace for O atoms in TiO2 lattice. The onset of the absorption spectrum of Fe/N-TiO2 has a 45 nm red-shift compared with that of TiO2. The results of photocatalytic degradation of methylene blue solution indicate that Fe/N-TiO2 (0.45% Fe3+) has a higher activity. Its photocatalytic activity is about 2 times as high as that of pure TiO2 under UV-light, and 3 times under sunlight. Doping of nitrogen in TiO2 enhances photoresponse in visible light region and doping of Fe3+ reduces the recombination of electrons and holes. Both of the above effects are beneficial for improving the performances of Fe/N-TiO2 photocatalyst

Hydrophilicity of TiO2 thin films codoped with iron and nitrogen

TiO2 doped with iron (Fe-TiO2) thin films were synthesized using sol-gel method. TiO2 codoped with iron and nitrogen (Fe/N-TiO2) thin films were prepared by calcining Fe-TiO2 thin films in ammonia atmosphere. The influence of iron and nitrogen doping concentration, heat-treatment temperature and film thickness on the hydrophilicity of the films were studied by XRD, XPS, SEM, UV-Vis spectra and measured water contact angle. The results indicated that Fe/N-TiO2 (0.5%Fe, molar percent) films were optimum in hydrophilicity, especially under visible-light irradiation. Doping iron mostly reduced the recombination of electrons and holes, and doping nitrogen in TiO2 enhances photoresponse in visible-light region. The hydrophilicity benefited from both effects

The effects of ocean acidification on marine organisms and ecosystem

海洋酸化是CO2排放引起的另一重大环境问题.工业革命以来,海洋吸收了人类排放CO2总量的三分之一.目前,海洋每年吸收的量约为人类排放量的四分之一(即约每小时吸收100万吨以上的CO2),对缓解全球变暖起着重要的作用.然而,随着海洋吸收CO2量的增加,表层海水的碱性下降,引起海洋酸化.海洋酸化会引起海洋系统内一系列化学变化,从而影响到大多数海洋生物的生理、生长、繁殖、代谢与生存,可能最终导致海洋生态系统发生不可逆转的变化,影响海洋生态系统的平衡及对人类的服务功能.地球历史上曾多次发生过海洋酸化事件,伴随着生物种类的灭绝,其内在联系虽然不甚明确,却也可能暗示未来海洋酸化可能对海洋生态系统产生重大的影响.Ocean acidification is known as another global change problem caused by increasing atmospheric CO2.Since the industrial revolution, the oceans have absorbed more than one third of the anthropogenic CO2 released to the atmosphere, currently, at a rate of over 1 million tons per hour, totaling to about one quarter of all anthropogenic CO2 emissions annually.Uptake of CO2 by the ocean has played an important role in stabilizing climate by mitigating global warming.However, rising ocean carbon levels caused by the uptake of anthropogenic CO2 (acidic gas) leads to increased ocean acidity (reduced pH) and related changes in ocean carbonate chemistry, or "ocean acidification".Recent research has shown that ocean acidification affects the physiology, growth, survival, and reproduction of many, if not most marine organisms.Ultimately, future ocean acidification may lead to significant changes in many marine ecosystems, with consequential impact on ecosystem services to societies.Several ocean acidification events are known to have occurred during Earth’s history, each coinciding with high rates of species’ extinctions.Although the mechanisms involved in past massive species extinction associated with ocean acidification events, they certainly hint potential disastrous impacts on ecosystem functions in short future.中国科学院“百人计划”(2006-067); 国家自然科学基金(40872168)资

TiO_(2-x) Thin Film Prepared by RF Magnetron Sputtering and Its Effects on UV-Vis Absorption

[中文文摘]用射频反应磁控溅射法,250℃时在石英玻璃片上沉积TiO2-x薄膜,用XRD、SEM、XPS、UV-Vis等对其进行表征.结果表明:未经热处理的薄膜呈锐钛矿型,薄膜表面粗糙,粒径约为30 nm的小晶粒聚集在一起,形成一个个“小层”,层层错叠;经600℃保温2 h热处理的薄膜呈金红石型,晶粒较大,孔隙变大.XPS分析发现:未经热处理的薄膜表面存在着20%的三价钛,有与之相对应的较多的氧空位;经600℃在空气中热处理后,三价钛减少到8%,同时氧空位减少.UV-Vis吸收表明,氧空位的存在有利于TiO2-x的吸收边向可见光波段移动.[英文文摘]TiO2-x films were prepared on quartz(SiO2) substrates at 250℃ by reactive radio-frequency(RF) magnetron sputtering,then heated at 600℃ in air for 2 h.The films with and without heat-treatment were characterized by XRD,SEM,XPS and UV-Vis.The films with and without heat-treatment presented rutile and anatase polycrystalline structure,respectively.Rough surfaces were obtained for all the films.For the film without heat-treatment,about 30 nm sub-grains grouped together into agglomeration to form layer-over-layer st ructure. Af ter heated at 600 ℃,the gain size became larger ,the pores got bigger. According to XPS analyses , there were 20% Ti3 + and more oxygen vacancies in the lattice of the film without heat2t reatment ,while 8% Ti3 + for the films heated at 600 ℃. The existence of oxygen vacancies helps the absorption edge extend to visible light according to the comparison in UV-Vis absorption.国家自然科学基金(50472057)资

The Cause of the ＂fun run＂ Phenomenon,the Bottleneck of Development and the Countermeasure Research——Analysis from the Perspective of Sociology

曾被年轻人"抗拒"的长跑运动,近年来,受到越来越多的年轻人推崇,风生水起的马拉松赛事和草根长跑活动就是佐证。运用文献资料法、逻辑分析法等研究方法,从社会学视角,分析了"乐跑"背后的社会原因及"乐跑"发展的瓶颈,认为,长跑运动相关事的包装、媒体对长跑活动的助推以及长跑运动特有的运动体验和功能,是形成"乐跑"现象的主要原因。然而,也存在硬件条件、安全问题等因素,制约这一"潮流"的良性发展,提出了"乐跑"现象发展的一些思考。Young people have been ＂ resist＂ long-distance running,in recent years,by more and more young people respected,wind and water from the marathon and grass-roots long-distance running is evidence. This paper analyzes the social reasons behind the ＂ fun run＂ and the bottleneck of the development of ＂ fun run＂ from the perspective on sociology,and points out that the packaging of the long-distance running related activities. Boost and long-distance movement unique sports experience and function,is the formation of ＂ fun run＂ phenomenon of the main reasons. However,there are also hardware conditions,security issues and other factors,restricting the ＂ trend＂ of the benign development and put forward some thoughts on the development of ＂ fun run＂ phenomeno