二氧化钛基纳米复合光催化材料的制备方法及应用研究进展

TiO₂光催化剂在环境污染控制领域有着良好的应用前景,一直是光催化材料研究的热点。由于TiO₂的禁带宽度大、光生电子和空穴迁移能力低等缺点限制了在可见光照射下的光催化效率;为了克服TiO₂的局限性,人们对TiO₂进行了改性研究,以提高TiO₂在可见光下的光催化活性。本文综述了近年来二氧化钛基纳米复合光催化材料的制备方法,介绍其在污水处理、生物医药、农业生产等领域的应用。     

石墨烯/TiO2复合材料光催化降解有机污染物的研究进展

石墨烯是一种新型的碳纳米材料,具有超大的比表面积和优良的导电性能,将石墨烯与TiO₂复合可显著提高复合材料的光催化性能,在光催化领域具有广泛的应用前景。主要介绍了石墨烯/TiO₂复合纳米材料的制备方法以及在光催化降解有机污染物方面的应用,并分析了石墨烯/TiO₂复合材料促进光催化机理,最后对石墨烯/TiO₂复合光催化剂未来的发展趋势提出了展望。     

新型TiO2基光催化剂改性降解VOCs的研究进展

实现有机污染物(VOCs)高效清洁降解是生态环保领域亟待解决的问题。光催化技术成为解决VOCs的有效方法之一,TiO₂半导体光催化剂作为最成熟的一种光催化剂,具有催化效率高、绿色、成本低的特点,但由于TiO₂光量子效率低,电子—空穴对易复合,无法产生可见光响应等缺陷,使得TiO₂光化材料无法广泛高效的应用。文章综述了改性TiO₂基光催化材料降解VOCs的研究进展,介绍了TiO₂光催化降解VOCs的作用机理,梳理归纳并总结了近些年TiO₂光催化降解VOCs的改性研究,并对未来开发新型TiO₂基光催化材料降解VOCs提出展望。     

TiO2光催化技术降解印染废水的研究进展

由于TiO₂光催化技术具有无毒、稳定性好、材料易得和氧化能力强的特性,在印染废水前处理及深度处理工艺中具有较好的应用前景。文章阐述了TiO₂光催化降解有机污染物的机理,对近年来国内外不同Ti O₂改性方法进行了综述,分析了TiO₂光催化技术在处理印染废水时的效果,并对未来Ti O₂光催化技术在降解印染废水中的应用进行了展望。     

TiO2/生物炭复合催化剂在染料废水处理中的应用

介绍了生物炭的特点及TiO₂掺杂生物炭的制备与表征方法,综述了生物炭及TiO₂/生物炭催化剂在处理染料废水方面的应用,分析了TiO₂及TiO₂/生物炭光催化降解的反应机理,并展望了TiO₂/生物炭在光催化降解染料领域的发展方向。     

光催化剂TiO2的改性研究进展

光催化剂TiO₂在环境污染治理领域呈现出广阔的应用前景,但由于其自身存在不能响应可见光和量子效率低的缺陷而限制了它的应用,改性是提高TiO₂光催化性能的重要手段。在总结国内外科研成果的基础上,综述了现阶段TiO₂的主要改性方法（如光敏化、离子掺杂、复合半导体等）研究进展,并对TiO₂改性方法的发展趋势进行了展望。     

提高二氧化钛孔道中水分子扩散性的分子模拟

众所周知,二氧化钛(TiO₂)材料在光催化材料、生物材料、电化学和工业催化等多个领域表现出优异的性能,因而其在解决能源和环境危机中被寄予厚望。在上述TiO₂材料的众多应用中往往都离不开水分子与TiO₂材料的接触。TiO₂表面结构,特别是水分子在TiO₂表面上形成的微结构往往对于TiO₂材料的应用起到关键作用。另一方面,大比表面积的TiO₂材料表现出性能上的优势,因此制备具有纳米孔道结构的TiO₂材料成为研究趋势。结合上述两点,水分子受限于TiO₂纳米孔道中的行为成为研究的热点之一。以往的研究结果表明,水分子在TiO₂表面具有强吸附作用,而该作用会影响到水分子在TiO₂孔道中的流动性。本文意在通过分子模拟的研究,找到提高水分子TiO₂孔道中扩散性的方法,并解释流动性增加的原因,为实验研究工作者们提供指导和解释。通过调整多项模拟参数,结果表明对于实验工作更为可靠的方法是用碳层覆盖TiO₂的表面。这样可以在不改变原有实验条件的基础上大大提高水分子在TiO₂孔道中的扩散性。     

Au对TiO2光电催化材料的改性策略研究进展

近年来,环境污染、能源枯竭问题日益严重,成为制约人类生存与发展的主要因素。光电催化技术能够同时实现污染物的降解与清洁能源的制备,有助于缓解环境污染与能源枯竭问题。作为典型的光（电）催化材料,TiO₂具有光活性强、性质稳定、廉价易得、环境友好等诸多优点,数十年来已成为光催化及相关领域的研究热点。然而,TiO₂存在的本征缺陷依然制约着其进一步推广应用,为此研究人员已提出多种方式对TiO₂进行改性。其中贵金属/TiO₂复合材料可显著提升TiO₂的光学活性并拓宽其吸收波长范围,尤其是Au/TiO₂材料体系已受到广泛关注和认可,表现出良好的应用前景。本文通过对目前Au/TiO₂复合材料的发展现状进行了总结,首先简单介绍了Au和TiO₂的化学性质及Au对TiO₂光学性能的增强原理;随后对Au/TiO₂复合材料的改性策略及相关作用机制展开讨论,包括Au对TiO₂光学性能的影响及调控、修饰方法的选择与影响等;最后总结出目前Au/TiO₂复合材料依然以克服TiO₂的两大本征缺陷为主,探讨各类新型Au/TiO₂复合材料有望使其得到逐步推广与实际应用。最后对目前Au/TiO₂复合材料的研究现状进行系统总结并探讨该材料未来的研究和发展方向。     

改进TiO2光催化降解水体中萘普生的研究

为解决TiO₂光催化降解水体中萘普生时易团聚、低活性的问题，对P25 TiO₂和石墨烯进行表面修饰，直接混合制得改进TiO₂催化剂，随后将其用于光催化降解水体中的萘普生，并研究降解动力学、作用机制以及生物毒性。XRD、FTIR、SEM表征结果表明，TiO₂经过修饰后引入了氨基，与改性石墨烯引入的含氧基团之间存在静电引力和化学键力，在这些力的作用下，TiO₂较好地接枝在石墨烯的表面。暗吸附、生物毒性、催化和猝灭实验结果表明，在500 W氙灯光照条件下，依靠石墨烯的协助，TiO₂在50 min内能将10 mg/L的萘普生接近完全矿化，矿化方式主要为h⁺与·OH协同氧化，生物毒性由母体的25.23%降至11.67%。实验结果表明改进TiO₂的制备方法直接、简单、可靠，可较好地解决P25 TiO₂易团聚、低活性的问题，是一种具有潜在应用前景的光催化材料。     

Ag/TiO2/PVDF复合纤维膜的制备及光催化性能研究

采用静电纺丝结合溶胶法制备了一系列不同Ag/TiO₂含量的Ag/TiO₂/PVDF复合纤维膜，并利用傅里叶红外光谱(FT-IR)、扫描电镜(SEM)、干湿重法、过滤测试法、微电脑抗张强度测定仪等对复合纤维膜的微观形貌、力学性能等进行表征和研究，结果表明添加适当的Ag/TiO₂时，所制备的Ag/TiO₂/PVDF复合纤维膜纤维表面比较平滑，具有较大的平均孔径和较高的孔隙率，且抗拉强度和伸长率均有所提高，但如过量添加Ag/TiO₂，则会导致膜性能受到影响。对Ag/TiO₂/PVDF复合纤维膜光催化降解溶液中亚甲基蓝(MB)的性能进行研究，结果表明，相较于PVDF原膜，Ag/TiO₂/PVDF复合纤维膜对于MB的光催化降解性能有显著提升，且其光催化降解过程符合准一级动力学模型。循环利用性能测试结果表明，Ag/TiO₂/PVDF复合纤维膜重复利用性较好，具有实际应用前景。     

Recent progress on nanostructure-based broadband absorbers and their solar energy thermal utilization

Nanostructure-based broadband absorbers are prominently attractive in various research fields such as nanomaterials,nanofabrication,nanophotonics and energy utilization.A highly efficient light absorption in wider wavelength ranges makes such absorbers useful in many solar energy harvesting applications.In this review,we present recent advances of broadband absorbers which absorb light by nanostructures.We start from the mechanism and design strategies of broadband absorbers based on different materials such as carbon-based,plasmonic or dielectric materials and then reviewed recent progress of solar energy thermal utilization dependent on the superior photo-heat conversion capacity of broadband absorbers which may significantly influence the future development of solar energy utilization,seawater purification and photoelectronic device design.     

光学膜保温性能的研究

研究了光学干涉膜对光的选择性,分析了其厚度对最大反射峰的影响。采用自制的隔热效果测试装置对干涉膜的隔热效果进行了测定。研究表明干涉膜反射光的波长范围主要由其厚度决定,随着光学厚度的增加,主要反射光波波长位置逐渐从较短区域向较长区域迁移;在红外灯照射下干涉膜和空白玻璃之间的温差最高可达2.4℃。     

光子晶体增强三线态-三线态弱光上转换发光特性研究

基于三线态-三线态湮灭机制的长波激发短波发射的弱光频率上转换,由于所需激发光能量接近太阳光强度,在太阳能电池、光催化降解和生物成像等领域显现诱人应用前景。本文采用无皂乳液聚合法制备纳米尺寸的聚苯乙烯-甲基丙烯酸甲酯-丙烯酸(P(St-MMA-AA))单分散乳胶微球,通过控制表面活性剂用量来调控乳胶微球尺寸大小,并利用竖直沉积法制备获得与上转换发光体系匹配的光子晶体薄膜。研究表明,该光子晶体可有效增强双组份体系的上转换发光。为弱光上转换技术走向应用探索一条新途径。     

Photocatalytic degradation of trichloroethylene over TiO<Subscript>2</Subscript>/SiO2 in an annulus fluidized bed reactor

The effects of superficial gas velocity (Ug), wavelength and intensity of ultraviolet (UV) light, oxygen and H₂O concentration on the photocatalytic degradation of TCE (Trichloroethylene) over TiO₂/SiO₂ catalyst have been determined in an annulus fluidized bed photoreactor. The key factor in determining the performance of the annulus fluidized bed photoreactor is found to be an optimum superficial gas velocity (Ug) that provides the optimum UV lighttransmit through the proper size of bubbles in the photoreactor. The degradation efficiency of TCE increases with light intensity but decreases with wavelength of the UV light and H₂O concentration in the fluidized bed of TiO₂/silica-gel photocatalyst. The optimum concentration of O₂ for TCE degradation is found to be approximately 10%. The annulus fluidized bed photoreactor is an effective tool for high TCE degradation with efficient utilization of photon energy. This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University.     

Upconversion in solar cells

The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Modification of the spectrum requires down- and/or upconversion or downshifting of the spectrum, meaning that the energy of photons is modified to either lower (down) or higher (up) energy. Nanostructures such as quantum dots, luminescent dye molecules, and lanthanide-doped glasses are capable of absorbing photons at a certain wavelength and emitting photons at a different (shorter or longer) wavelength. We will discuss upconversion by lanthanide compounds in various host materials and will further demonstrate upconversion to work for thin-film silicon solar cells.     

聚氯乙烯的紫外光降解机理及影响因素

介绍了聚氯乙烯(PVC)的紫外光降解机理。PVC的立构规整性、溶剂、增塑剂、热稳定剂和颜料及PVC的共混物一般被认为是光降解的主要影响因素,紫外光波长及制品厚度会对紫外光降解过程产生一定影响。作为该领域的研究热点之一,有关光降解的研究不仅有利于防止PVC制品在一般场合下的过快降解,而且有益于合理利用PVC作为环保材料时的光降解特性。     

A novel photochromic material based on halophosphate: Remote light-controlled reversible luminescence modulation and fluorescence lifetime regulation

Luminescent material Ca₂Ba₃(PO₄)₃F:Eu²⁺ displays green emitting in the range of 400–700?nm, which is ascribed to the 4f⁶5d¹ →4f⁷ transition of Eu²⁺ ions. Amazingly, the body color of the samples can be changed between colorless and green upon alternative UV and visible light irradiation/heating treatment with robust fatigue resistance due to photochromism. The photochromic effect strongly depends on the Eu²⁺ doping concentration. After remote-controlled short-UV irradiation, the overall Eu²⁺ emission intensity presents a significant decrease, and inversely, exhibits an increase to the initial level after illuminated by longer wavelength light or heat treatment. Moreover, the fluorescence lifetime also can be regulated reversibly, of which the regulation degree depends on the short-UV irradiation and longer wavelength illumination time/heating temperature. A schematic diagram based on energy levels is proposed to illustrate the photochromism mechanism.     

Structural and Functional Change in Albino Rat Retina Induced by Various Visible Light Wavelengths

The effects of visible light, from short to long wavelengths, on the retina were investigated functionally and histologically. The left eyes of Sprague–Dawley albino rats (6-weeks old, n = 6 for each wavelength) were exposed to seven narrow-band wavelengths (central wavelengths, 421, 441, 459, 501, 541, 581, and 615 nm) with bandwidths of 16 to 29 nm (half bandwidth, ±8–14.5 nm) using a xenon lamp source with bandpass filters at the retinal radiant exposures of 340 and 680 J/cm². The right unexposed eyes served as controls. Seven days after exposure, flash electroretinograms (ERGs) were recorded, and the outer nuclear layer (ONL) thickness was measured. Compared to the unexposed eyes, significant reductions in the a- and b-wave ERG amplitudes were seen in eyes exposed to 460-nm or shorter wavelengths of light. The ONL thickness near the optic nerve head also tended to decrease with exposure to shorter wavelengths. The decreased ERG amplitudes and ONL thicknesses were most prominent in eyes exposed to 420-nm light at both radiant exposures. When the wavelengths were the same, the higher the amount of radiant exposure and the stronger the damage. Compared to the unexposed eyes, the a- and b-waves did not decrease significantly in eyes exposed to 500-nm or longer wavelength light. The results indicate that the retinal damage induced by visible light observed in albino rats depends on the wavelength and energy level of the exposed light.     

Über den Einfluß von Licht verschiedener Intensität und Wellenlängenbereiche auf den oxydativen Verderb von Speiseölen II: Versuchsergebnisse und Diskussion

Influence of Light of Varying Intensity and Wavelength on the Oxydative Deterioration of Edible Oils II: Experimental Results and Discussion Since the action of light is a major cause for the deterioration of oils and fats, light-catalyzed oxidation of refined soybean oil was carried out under defined conditions of intensity and wavelength and the quantum yields were calculated. Not only was the intensity of light varied at a constant wavelength but also, in contrast to hitherto known work, the quantum density was held constant at various wavelengths. The photochemical action was dependent on the wavelength and the former increased with decreasing wavelength to a much greater extent than as might have been expected from the energy content of the light quantum.     

光催化环己烷选择氧化合成环己酮/环己醇催化研究进展

环己烷选择性氧化合成环己醇/酮具有重要工业价值,工业上热氧化路线反应温度高、副反应多、转化率低、选择性不高,亟需条件更温和、更环保的替代路线。以太阳光为驱动的光催化环己烷氧化路线可在常温常压下实现环己烷的选择性氧化,受到极大关注。本文综述了近10年来光催化环己烷选择性氧化催化体系、反应机理和反应影响因素的研究情况,对光催化环己烷选择性氧化催化循环中环己烷分子活化、环己酮/醇形成、活性自由基再生的基元过程和催化剂失活机理进行总结和分析;对影响光催化环己烷选择性氧化的反应参数进行深入分析和讨论;指出·OH为主要的活性自由基,环己基过氧化氢是重要的中间产物,环己酮/醇主要通过环己基过氧化氢的光催化分解形成,光辐射条件（光强和波长）、溶剂、催化剂结构和表面性质都是光催化环己烷选择性氧化的重要影响因素。最后指出光催化环己烷选择性氧化规模化应用的关键是进一步提高光催化剂的寿命和稳定性以及设计结构合理、高效利用光能的光催化反应装置。