基于表面等离子体共振效应的Ag(Au)/半导体纳米复合光催化剂的研究进展

由具有表面等离子体共振(surface plasmon resonance,SPR)效应的贵金属(Ag、Au等)纳米粒子和半导体纳米结构组成的纳米复合光催化剂具有优异的可见光光催化活性,成为新型光催化材料的研究热点之一。本文综述了Ag(Au)/半导体纳米复合光催化剂的制备方法、基本性质以及光催化应用方面的一些重要研究进展;重点介绍了Ag(Au)等纳米粒子的表面等离子共振增强可见光催化活性的机理,以及Ag(Au)纳米粒子与不同类型半导体复合的光催化剂的光催化性能,其中所涉及的半导体包括金属氧化物、硫化物和其他一些半导体;本领域未来几年的研究热点将集中于新型高效的Ag(Au)/半导体纳米复合光催化剂的微结构调控及其用于可见光驱动有机反应的机理研究。本文为基于SPR效应构建Ag(Au)/半导体纳米复合光催化剂的研究提供了有力的参考依据,并且指出Ag(Au)/半导体纳米复合光催化剂的研究是发展可见光高效光催化剂的重要方向。     

钛酸纳米管光催化剂的改性研究进展

钛酸纳米管具有高比表面积和光化学稳定性等特点,在光催化领域得到广泛的研究。为了拓宽可见光吸收范围和提高量子产率,需要对其进行改性。本文介绍了金属离子掺杂、贵金属沉积及复合半导体对钛酸纳米管光催化剂的改性研究最新进展,分别从实验制备及掺杂后的光催化特性入手,分析了各种改性方法的作用机理。最后指出了钛酸纳米管改性的进一步研究方向。     

TiO_2光催化降解有机染料反应机理

叙述了近年来国内外金属离子掺杂、贵金属沉积、半导体复合二氧化钛在光催化降解有机染料反应机理研究进展,以进一步揭示在TiO_2修饰改性反应机理研究中所面临的主要问题及今后改进措施,认为已开发的新型TiO_2光催化剂的光催化反应机理的研究,还处于初步设想及推测阶段,仍然需要实验进行验证。对于掺杂TiO_2光催化剂,尽管研究发现了多种可见光响应的光催化剂,但是大多数光催化反应效率较低,必须探究其它不同修饰剂对TiO_2的光吸收和光催化协同效应机理、光生电子与空穴在修饰条件下发生分离的机理,尤其是金属与非金属共同掺杂TiO_2光催化降解有机染料反应机理将是一个重要研究方向。     

改性纳米TiO_2可见光催化性能分析

在繁杂多变的催化剂之中,作为最早应用于解决能源和环境问题的半导体光催化剂,TiO_2因其高活性、性质稳定、廉价易得、安全无毒等优势如今依旧耀眼。得益于70年代开始不断进步的纳米技术,TiO_2纳米粒子、纳米棒、纳米管等具备纳米效应的光催化材料以不同方法被制备,TiO_2的光催化活性得到了很大改善。本文将基于改性纳米TiO_2的机理,结合影响改性纳米TiO_2可见光催化性能的因素分析,从离子掺杂、贵金属沉积和半导体复合三个实验途径,提升了改性纳米TiO_2可见光催化活性与性能。     

提高纳米二氧化钛可见光光催化活性研究的进展

综述了近年来提高纳米TiO2可见光光催化活性的研究,主要包括:对纳米TiO2进行表面复合与衍生、金属离子掺杂、半导体偶合、非金属元素掺杂改性和染料敏化等技术,并分析了各种不同掺杂改性机理.最后,展望了提高纳米TiO2可见光光催化活性研究进展的前景.     

红磷光催化材料的研究进展

红磷作为一种可见光响应的半导体光催化剂，具有廉价易得、化学性质稳定、低毒以及合适的带隙等优点，但也存在商业红磷比表面积小以及光生电子-空穴对复合严重等问题，需要对其进行改性以提高光催化性能。本文着重评述了红磷在形貌调控、表面修饰、复合调控和构建异质结等改性手段方面的研究进展以及改性催化剂在降解有机污染物、分解水制氢等方面的应用。最后指出未来的研究方向在于同时用多种手段改性、拓展红磷在光催化领域的应用和深入进行机理探索等方面。     

铋系半导体光催化材料的改性

铋系半导体光催化剂是近年来较热门的一类光催化剂,大多具有各向异性的层状结构与合适的禁带宽度,其可见光响应性能好,在环境及能源领域有着广阔前景。然而其依然存在对可见光的吸收有限、光生电子-空穴易复合的问题。介绍了近年来对铋系半导体光催化材料(铋的氧化物、含氧酸盐、卤氧化物等)改性的手段,包括形貌结构调控、表面修饰、构建异质结和组成调控,阐述了改性的效果以及机理,并对其今后发展的前景进行了展望。     

聚苯胺改性负载型纳米二氧化钛的研究

采用悬浮聚合法制备聚苯乙烯微珠载体,通过矿化接枝技术将溶胶-凝胶法制备的纳米二氧化钛负载在微珠载体上,制成负载型纳米二氧化钛光催化剂。利用导电聚苯胺对负载型纳米二氧化钛光催化剂进行可见光改性研究,通过XRD,SEM等方法对负载型纳米二氧化钛光催化剂进行表征;通过光催化降解甲基橙实验评价了导电聚苯胺改性负载型纳米二氧化钛光催化剂在可见光条件下的光催化活性。实验结果表明：导电聚苯胺对负载型纳米二氧化钛光催化剂的改性,可有效改善负载型纳米二氧化钛光催化剂在可见光条件下的光催化性能,降解率提高了24.5%。     

半导体核壳材料光催化剂分解水制氢研究进展

光催化剂催化分解水制氢是一种将太阳能有效转化为氢能的绿色途径，其中半导体核壳材料光催化剂在太阳能分解水制氢中表现出优异的性能。主要从半导体材料改性角度出发，综述和评论了国内外半导体核壳材料光催化剂分解水制氢的最新研究进展。重点阐述了常见氧化物、氮氧化物、氮化物及硫化物核壳材料半导体光催化剂分解水制氢的基本原理和改性效果等。分析了掺杂离子、构建异质结、负载助催化剂等改性方法在改变光催化剂禁带宽度、降低光生载流子复合几率、加快光生电荷传输速率和增加制氢活性位点等方面的影响。提出未来分解水制氢光催化剂可深入开发晶面依赖纳米复合光催化材料、助剂改性光催化材料、新型光催化半导体材料的研究方向。     

半导体光催化剂的研究现状及展望

半导体光催化氧化技术是一种新型的现代化水处理技术,对多种有机物有明显的降解效果,具有广泛的前景.本文简要综述了半导体光催化剂的研究开发现状,并对存在的问题和未来的发展动向进行简要分析.列举了近几十年来关于光催化研究的部分成果,内容涉及到光催化作用机理、光催化剂类型、TiO2半导体光催化剂的改性、光催化剂的固定化等各方面.最后,指出了存在的问题及今后的研究趋势.     

Visible-Light-Induced Photocatalytic Inactivation of Bacteria by Composite Photocatalysts of Palladium Oxide and Nitrogen-Doped Titanium Oxide

Composite photocatalysts of palladium oxide and nitrogen-doped titanium oxide (PdO/TiON) were synthesized by a sol–gel process, as convenient forms of nanopowder or immobilized powder on nanofiber. The PdO/TiON catalysts were tested for visible-light-activated photocatalysis using different bacterial indicators, including gram-negative cells of Escherichia coli and Pseudomonas aeruginosa, and gram-positive cells of Staphylococcus aureus. Disinfection data indicated that PdO/TiON composite photocatalysts have a much better photocatalytic activity than either palladium-doped (PdO/TiO₂) or nitrogen-doped titanium oxide (TiON) under visible-light illumination. The roles of Pd and N were discussed in terms of the production and separation of the charge carriers under visible-light illumination. The photocatalytic activity was thus dependent on dopants and light intensity. Microscopic characterization demonstrated that visible-light photocatalysis on PdO/TiON caused drastic damage on the bacteria cell wall and the cell membrane.     

ZnS:Cu powders with strong visible-light photocatalysis and pyro-catalysis for room-temperature dye decomposition

In this work, strong visible-light photocatalysis and pyro-catalysis for dye decomposition was observed in hexagonal wurtzite phase ZnS:Cu. As described herein, ZnS:Cu ceramic is shown to be a visible-light-responsive material with a band gap of ~2.77 eV. Under visible-light irradiation, the photocatalytic decomposition ratios of ZnS:Cu on 5 mg/L Rhodamine B, methylene blue, and acid orange 7 solutions reach 99.2%, 95.9%, and 78.8%, respectively. With respect to pyro-catalysis results, the decomposition ratio for acid orange 7 in the same concentration is 82.2%. For photo-/pyro-bi-catalysis, the decomposition ratio can reach ~95%. In summary, the ZnS:Cu ceramics exhibit strong visible-light photocatalysis and pyro-catalysis, making it a viable solution for decomposing synthetic dyes wastewater through utilizing the visible-light energy and cold-hot cycling.     

Covalently synthesized graphene oxide-aptamer nanosheets for efficient visible-light photocatalysis of nucleic acids and proteins of viruses

A novel photocatalyst, graphene oxide (GO) functioned aptamer, was covalently synthesized and characterized as being composed of photosensitive GO and target recognition aptamer. Aptamer enhanced photocatalytic activities of GO were studied under broad visible-light spectrum. The complex photocatalyst effectively inactivated viruses, and damaged the proteins capsid and nucleic acids of viruses in irradiation. Subsequently, the proteins posed carbonylation and the nucleic acid bases (especially for guanosine) received oxidized modification. GO was reduced by loss of oxygen elements. GO-aptamer and viruses constituted a redox system under visible-light irradiation. The photocatalysis paths involved energy transfer (generation of singlet oxygen), electron transfer (generation of anion radicals) and water dissociation (generation of the precursor to the hydrated electron). GO-aptamer is a smart photocatalyst to selectively photocatalyze of nucleic acids and proteins, which is attractive in environment protection, biochemical engineering and phototherapy.     

可见光催化降解水中卤代有机污染物的研究进展

卤代有机污染物（HOCs）在水环境中检出频率高达45%,由于其具有毒性大、持久性强和易累积等特点,该类污染物引发的环境问题已引起越来越多的关注。可见光催化技术具有高效太阳能利用率、强选择性及反应条件温和、处理费用低等优点,对于降解水中HOCs具有独特的处理优势,因此近年来被广泛研究。本文梳理了可见光催化降解水中HOCs的核心脱卤机制,包括氧化脱卤、还原脱卤和水解脱卤,在脱卤机制的基础上汇总了三大类主流催化剂的脱卤贡献率,主要包括金属基光催化剂、碳基光催化剂及其他新型光催化剂三类光催化材料。基于可见光作用下降解水中HOCs的应用案例分析,探讨了光催化反应过程中的主要影响因素是溶液pH、催化剂用量及反应温度等。可见光催化降解去除效率高是本技术的核心优势,但由于催化剂的成本高和选择性差导致了其无法大规模应用,未来可见光催化材料设计应向成本低廉、精准匹配污染物从而实现高选择性的方向改进。     

非金属掺杂的第二代二氧化钛光催化剂研究进展

寻求廉价、环境友好并具有可见光光催化活性的第二代光催化剂将是光催化发展进一步走向实用化的关键。氮掺杂的TIO2是新发现的具有可见光光催化活性的复合光催化剂,非金属掺杂可以使复合物的复合禁带宽度小于TIO2的禁带宽度,从而使TIO2的吸收边向可见光移动。对TIO2的氮、碳、硫、卤素掺杂国内外研究现状进行了系统评述,分析了提高TIO2可见光活性的原因,指出非金属元素特别是氮元素的阴离子掺杂是在不降低紫外光催化活性的基础上实现可见光响应的较好方法。     

Co-precipitation synthesis,band modulation and improved visible-light-driven photocatalysis of Te4+/Ti4+-codoped Bi3Nb17O47

Bismuth niobate semiconductors are of considerable interest in both contaminant degradation and H₂-generation. However, the wide band gap strictly limits the optical absorption in visible-light wavelength. In this work, a new niobate semiconductor Bi₃Nb₁₇O₄₇ was prepared with co-precipitation synthesis. To modify the band structure, Te⁴⁺-, Ti⁴⁺-, and Te⁴⁺/Ti⁴⁺-doping were conducted in Bi₃Nb₁₇O₄₇ lattices. Rietveld refinements were used to investigate the crystal phase and structure. The UV–vis absorption measurements concluded that Te⁴⁺-, Ti⁴⁺- doping could greatly modify the band energy of Bi₃Nb₁₇O₄₇. The Te⁴⁺/Ti⁴⁺-doped sample could harvest more visible light in the longer-wavelength region being favorable for photocatalysis performances. This was verified by RhB photodegradation tests under the visible-light irradiation (λ > 420 nm). To discuss the photocatalytic mechanisms, XPS and impedance spectra were measured. The improved photocatalysis was related to the microstructure changes, charge carrier dynamics, oxygen vacancies, and redox couples of multivalent ions. The present work provides a valid route to modify the band structure and to improve the photocatalysis abilities via impurity ions Te⁴⁺/Ti⁴⁺-doping in bismuth niobate semiconductors.     

Fe(Ⅲ)改性金红石TiO_2可见光催化H_2O_2降解阿特拉津的研究

以Fe(Ⅲ)改性金红石TiO_2(r-TiO_2)制备Fe/r-TiO_2,研究了Fe/r-TiO_2可见光催化H_2O_2降解阿特拉津的各种影响因素.结果表明,Fe/r-TiO_2在H_2O_2及波长不低于400mm的可见光协同作用下,控制反应体系的pH为3,H_2O_2的浓度为1 mmol·L~(-1),催化剂质量浓度为1 g·L~(-1),经1 h后,阿特拉津的降解率可达95%.     

Ag/g-C3N4 photocatalysts: Microwave-assisted synthesis and enhanced visible-light photocatalytic activity

Ag/g-C₃N₄ photocatalysts were synthesized by a rapid microwave-assisted polyol process. The characterization results showed monodisperse Ag nanoparticles with diameters of a few nanometers closely attached to the edges of g-C₃N₄. The presence of Ag nanoparticles in Ag/g-C₃N₄ photocatalysts enhanced the visible-light absorption and suppressed the recombination of photogenerated electron/hole pairs. The Ag/g-C₃N₄ photocatalysts exhibited the superior visible-light responsive photocatalytic activity for rhodamine B degradation. The mechanism of visible-light induced photocatalysis over Ag/g-C₃N₄ photocatalysts was also discussed.     

Enhanced visible-light-driven photocatalysis of surface nitrided electrospun TiO2 nanofibers

Enhanced visible-light-driven photocatalysis of TiO(2) nanofibers have been prepared by the electrospinning method combined with a surface nitridation process. The visible-light-driven photo-catalytic activity of surface nitrided TiO(2) (N-TiO(2)) nanofibers has been evaluated using rhodamine B indicator, and it was found that the visible-light-driven photocatalytic activity of the electrospun TiO(2) nanofibers could be enhanced by nitridation in NH(3) atmosphere. The optimal visible-light photocatalytic activity of N-TiO(2) nanofibers exceeded that of pure TiO(2) nanofibers by a factor of more than 12. The nitridation temperature under NH(3) flow was found to play an important part in the performance of N-TiO(2) nanofibers, and the optimum temperature is 500 °C. Structure, morphology and photoluminescence of these nanofibers were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and photoluminescence (PL) spectroscopy. The mechanism of the enhancement of visible-light-driven photocatalytic activity by surface nitridation has been discussed.     

TiO_2可见光催化的研究进展

综述了近年来国内外研究TiO2可见光催化反应的进展,如金属或非金属掺杂、染料光敏化、与其它半导体复合、与H2O2复合等,阐述了TiO2可见光催化的反应机制,指出了TiO2可见光催化存在的主要问题、发展前景及今后的研究方向。