拓展纳米TiO2作用光范围研究的进展

TiO2光催化剂在环境治理和能源开发方面具有广阔的应用前景，但其较宽的禁带宽度不能有效地利用太阳能，限制了它的应用范围。因此开发具有可见光响应的TiO2光催化剂将成为未来研究的主要方向。从染料敏化、半导体复合、金属离子和非金属离子掺杂等方面介绍了目前的研究现状，并对引入氧空位缺陷来改善其可见光催化活性进行了分析和展望。     

共掺杂改性TiO2光催化剂的研究进展

TiO2具备化学稳定性好、催化活性高、无污染、价格低廉等优点,在光催化领域有广阔的发展前景,但禁带宽度较大、可见光吸收能力差等缺点影响了TiO2在生产生活中的推广利用.本文综述了共掺杂改性TiO2在光催化领域的研究进展,介绍了纳米TiO2的光催化机理,分析比较了金属与金属共掺杂、非金属与非金属共掺杂、金属与非金属共掺杂三种改性方式对TiO2光催化性能的影响;指出共掺杂改性可以通过降低禁带宽度、产生可见光效应、抑制光生电子空穴复合等方式提高TiO2的光催化活性;总结了有关共掺杂作用机理和离子间协同作用的研究成果,提出了当下共掺杂改性TiO2研究存在的不足之处,并对今后的研究方向进行了展望.     

拓展纳米TiO2作用光范围研究的进展

TiO2光催化剂在环境治理和能源开发方面具有广阔的应用前景,但其较宽的禁带宽度不能有效地利用太阳能,限制了它的应用范围.因此开发具有可见光响应的TiO2光催化剂将成为未来研究的主要方向.从染料敏化、半导体复合、金属离子和非金属离子掺杂等方面介绍了目前的研究现状,并对引入氧空位缺陷来改善其可见光催化活性进行了分析和展望.     

氮掺杂TiO2光催化剂研究进展

对TiO2光催化剂进行改性,实现可见光催化活性是第二代光催化剂走向实用化的关键.氮掺杂TiO2是一种理想的具有可见光活性的光催化剂,由于N 2p态与O 2p态杂化,实现带隙窄化和吸收带边红移,对于实现可见光催化活性具有重要意义.评述了氮掺杂改性TiO2光催化剂的国内外研究现状,分析了不同掺杂方法对于实现TiO2可见光催化活性的掺杂机理和改性机理,提出研究合适的催化剂载体对TiO2进行氮等非金属负载是今后努力的方向,并且应该建立统一的催化剂性能评价标准.     

S掺杂改性TiO_2光催化剂的研究

TiO2具有无毒、化学性能稳定、价格便宜和不产生二次污染等特点,被认为是最有应用前景的光催化剂,但TiO2较宽的禁带宽度和低的量子转换效率限制了其实际应用。对TiO2进行改性以提高其在可见光区的光催化活性是近几年研究的热点。综述了S单掺及与其它离子共掺杂改性TiO2光催化剂的工作机理以及掺杂后对TiO2光催化性能的影响,介绍了国内外在该方面研究的主要进展,并讨论了TiO2光催化剂掺杂改性中存在的问题。     

非金属元素掺杂TiO2的可见光催化活性研究进展

TiO2(锐钛矿)的禁带宽度限制了其光诱导特性的广泛应用,非金属元素掺杂为TiO2在可见光辐射环境下的应用提供了新的机会.详细介绍了非金属元素(N、C、S、F)掺杂TiO2的制备方法和可见光催化活性研究的最新进展,讨论了制备工艺与掺杂TiO2可见光催化活性的关系,深入分析了非金属元素对TiO2可见光催化活性的诱导机理.制备工艺显著影响了掺杂元素的化学态和含量,从而决定了掺杂TiO2带隙中局域态的特征.带隙中局域态特征正是影响掺杂TiO2可见光催化活性的关键因素.文章也对未来的研究方向进行了展望.     

非金属阳离子掺杂锐钛矿相TiO2的第一性原理研究

采用基于第一性原理的平面波超软赝势方法研究了非金属阳离子掺杂锐钛矿相TiO2的晶体结构、杂质形成能、电子结构及光学性质.计算结果表明掺杂后发生的晶格畸变、原子间的键长及原子的电荷量的变化,导致了晶体中的八面体偶极矩增大,使光生电子-空穴对能有效分离; 掺杂离子的p态电子与O2p态、Ti3d态杂化形成杂质能级、价带宽化,从而导致TiO2的禁带宽度变窄、光吸收曲线红移到可见光区.这些计算结果很好地解释了非金属阳离子掺杂锐钛矿相TiO2在可见光下具有优良的光催化性能的内在原因.     

二氧化钛光催化剂的可见光响应研究进展

研究开发对可见光响应的纳米TiO2光催化剂是当前光催化研究领域的热门课题.概述了金属离子掺杂、非金属离子掺杂、表面光敏化、耦合半导体、引入氧空位等使二氧化钛可见光化的方法的研究现状.电荷传输与分离过程的变化使TiO2能有效地利用可见光,可见光化的程度取决于制备方法、热处理过程、掺杂物种类及浓度等.     

金属非金属共掺杂TiO2纳米管的研究进展

部分金属掺杂TiO2纳米管可以有效提高其光电转换效率;而很多非金属的掺杂可以拓宽TiO2纳米管的光谱响应范围从而提高对可见光的利用率。金属和非金属共掺杂则可以使两者协同作用。介绍了金属与非金属掺杂TiO2纳米管的机理、制备方法和研究现状,并在此基础上指出了现如今存在的问题并对其发展趋势进行了展望。     

Ta掺杂锐钛矿相TiO2的理论分析

采用基于密度泛函理论的第一性原理平面波超软赝势法,对Ta掺杂锐钛矿相TiO2的电子结构和光学吸收性质进行计算。结果表明,TiO2中掺杂Ta后,杂质能级与导带底混合,禁带宽度明显减小;杂质能级的引入和禁带宽度的减小使得Ta掺杂锐钛矿相TiO2光吸收在可见光范围内出现明显吸收增强。     

Efficient visible light driven photocatalytic removal of NO with aerosol flow synthesized B, N-codoped TiO2 hollow spheres

In this study, we demonstrate that aerosol assisted flow synthesized B, N-codoped TiO(2) photocatalyst possesses superior photocatalytic activity to pure and single element doped counterparts on the degradation of NO in a flow system under both simulated solar light and visible light irradiation. Characterization results revealed that B, N-codoped TiO(2) photocatalyst was composed of hollow microspheres. Boron and nitrogen were in the form of Ti-O-B and N-Ti-O structures, respectively. The introduction of B and N into the TiO(2) lattice could effectively tune the band gap of TiO(2) and extend its optical response to the visible-light region. The synergistic effect of B and N codoping on visible light driven photocatalytic activity enhancement of TiO(2) was discussed on the basis of experimental results.     

Synthesis and characterization of the N-doped TiO2 photocatalyst for the photodegradation of methylene blue and phenol

To extend the light absorption of TiO2-based photocatalysts towards the visible-light range and to eliminate the rapid recombination of excited electrons/holes during photoreaction, a new type of photocatalyst (N-doped TiO2) powder was prepared through a simple sol-gel process. The crystal phase composition, structure, and light absorption of the new photocatalyst were comprehensively examined via X-ray diffraction, ultraviolet-visible (UV-Vis) absorption spectroscopy, and atomic-absorption spectroscopy. The photo-oxidation efficiency of the photocatalyst was also evaluated in the photodegradation of methylene blue (MB) and of phenol in aqueous solutions under visible-light irradiation from a neon lamp (lambda > 400 nm). The results of the analyses that were performed in this study indicated that the N-doped TiO2 could eliminate the electron/holes recombination and could increase the light absorption in the visible range. The results of the analysis of the UV-Vis diffuse reflection and optical-absorption spectra indicated that a new energy level below 3.2 eV generated in the N-doped TiO2 promoted the optical absorption in the visible-light region and made visible-light excitation possible (E < 3.2 eV). The experiment demonstrated that the photo-oxidation efficiency of MB when N-doped TiO2 powder was used was significantly higher than that when the conventional TiO2 powders were used. The development of such photocatalyst may be considered a breakthrough in the large-scale utilization of solar energy to address the current and future environmental needs.     

纳米TiO2光催化剂可见光化的最新进展

TiO2是当前最具应用潜力的光催化剂之一，但仍然存在不足，主要表现在光吸收波长狭窄，吸收波长阈值在紫外区，摘要利用太阳光能量比例低等方面。对其进行改性，增加其光吸收波长范围，可以更充分地利用太阳光，达到节约能源的目的。因此，TiO2可见光化一直是研究热点。综述了近几年国内外最新的纳米TiO2可见光化改性的进展，如金属或非金属离子掺杂、贵金属沉积、有机染料光敏化、溶剂热法制备等，并对TiO2光催化剂的应用前景进行了展望，认为溶剂热法简便易行，应该重视和大力研究。     

A new approach toward carbon-modified vanadium-doped titanium dioxide photocatalysts

Carbon-modified vanadium-doped TiO? was successfully prepared with the intention of enhancing the visible-light photocatalytic performance by expanding the absorption in the visible-light region and improving the quantum efficiency of the photocatalytic reaction. The physicochemical properties of the catalysts were characterized by XRD, Raman, TEM, XPS, UV-vis diffuse reflectance spectra. The result indicated that some vanadium ions substituted for Ti?? in the lattice of TiO?, whereas all the carbon was modified on the surface of catalysts in the form of stable graphite-like carbonaceous species. Compared with vanadium doped TiO? sample and carbon modified TiO? sample, the 0.32C-0.5%V-TiO? photocatalyst exhibited excellent visible light activity and the synergistic effects of vanadium and carbon was responsible for improving the photocatalytic activity.     

一种可见光响应纳米 TiO2粉体的光响应特性表征

利用有机溶剂水热法制备了一种新型的可见光响应纳米TiO2粉体光催化剂．对其进行光响应特性表征，研究发现：固相粉末漫反射吸收谱反映了该TiO2粉体具有类似改性TiO2的可见光响应的特征；而在纳米颗粒稀悬浮液的特定条件下，紫外-可见吸收谱给出了该纳米TiO2粉体的类似本征TiO2的光响应特征，观测不到其可见光响应特征；分析表明，该现象可能与在稀悬浮液的条件下，声子参与的光致电子跃迁过程的退化有关．     

过渡金属Cr掺杂对金红石光性影响的研究

报道了采用高温扩散掺杂敏化法在金红石晶体表面掺入Cr离子、有效提高可见光响应的研究结果,分别利用UV－VIS、XFA、XRD和LRS等测试手段对样品进行了分析。结果表明Cr离子掺入晶体表面后以Cr2O3的形式与基体TiO2形成固溶体Cr2TiO5,提高了可见波段的光吸收,使原来位于410nm的TiO2的吸收边移到了750nm处,实现了与太阳光谱的匹配。     

过渡金属Cr掺杂对金红石光性影响的研究

报道了采用高温扩散掺杂敏化法在金红石晶体表面掺入Cr离子、有效提高可见光响应的研究结果.分别利用UV-VIS、XFA、XRD和LRS等测试手段对样品进行了分析.结果表明Cr离子掺入晶体表面后以Cr     

A study of parameter setting and characterization of visible-light driven nitrogen-modified commercial TiO2 photocatalysts

An optimal condition applied to the Taguchi method with an L(9) orthogonal array for preparing a visible-light driven nitrogen-modified TiO(2) (N-TiO(2)) photocatalyst by a simple hydrolysis method has been examined for material characteristics and a photodecolorization test of methyl blue (MB) under various visible light source (fluorescent and blue LED lamps) irradiations. Results of the material characterization showed that the absorption of prepared N-TiO(2) powder exhibited a significant extension into visible light regimes with an optical bandgap (Eg) of around 2.96 eV, which subsequently improved the visible-light photocatalytic activity of N-TiO(2) samples. The superior photocatalytic properties, the pseudo first-order reaction rate constants (k) and photodecolorization efficiency (η%) of a N-TiO(2) photocatalyst during the photodecolorization test of methyl blue (MB) under two different visible light irradiations were very evident compared to those for pure TiO(2). For photodecolorization of practical dyeing from the waste water from the dyeing and finishing industry, a higher photodecolorization efficiency of N-TiO(2) powder toward Direct blue-86 (DB-86) (Direct Fast Turquoise Blue GL) dye was also achieved.     

Low temperature preparation and visible light induced photocatalytic activity of europium doped hydrophobic anatase TiO2-SiO2 photocatalysts

The Eu(3+) doped TiO2-SiO2 photocatalysts, as a reclaimed visible-light responsive photocatalyst, were prepared by sol-gel method with TEOS, TBT and europium nitrate as precursors, by keeping the molar of TEOS:TBT constant at 1:1 and with different europium doping content. The resulting photocatalysts were characterized by XRD, TEM, SEM, EDX, UV-VIS DRS, FTIR and BET method. Analytical results demonstrated that only anatase phase is present in photocatalysts with high surface areas. The mean size is around 10 nm form TEM, which is consistent with the analytical result according to SEM. It can be seen methyl groups exist in photocatalysts based on analysis of FTIR and EDX. It was found that the resulting Eu(3+) doped photocatalysts exhibit higher photocatalytic activity than undoped photocatalysts and P25 on the degradation of rhodamine B(RhB, 10 mg/l) in water under visible light irradiation (lambda > 410). After irradiation for 3 h, the maximum absorption decreases gradually with irradiation time and absorption band shifts from 554 to 507 nm.     

非金属掺杂TiO2催化剂的制备及可见光诱导活性

通过金属及非金属离子掺杂改性、离子注入以及染料光敏化等方法可以将只能紫外光激发的TiO2光催化反应红移到可见光区域进行,近年来国内外在非金属掺杂TiO2可见光催化剂研究取得了积极进展。本文主要对N掺杂和C掺杂TiO2的制备方法进行了介绍,同时对其掺杂的非金属存在形态及掺杂机理作了理论分析。