TiO2掺杂改性提高光催化剂有机物降解能力技术研究进展

纺织行业生产过程中产生大量有机废水,严重危害环境及人体健康,降解废水中有机污染物成为近年来环保领域的研究热点。二氧化钛(TiO_2)的非均相光催化是有效降解有机污染物最有前途的技术之一。本文介绍了TiO_2的光催化机理并且从金属离子掺杂、非金属离子掺杂、半导体复合、染料敏化等方面综述了提高TiO_2光催化效率的研究进展。     

碳量子点与半导体复合光催化材料合成及降解有机污染物的应用进展

有机污染物的危害日益严重,引起人们的广泛关注。半导体光催化降解有机污染物是公认的绿色技术,但传统的半导体光催化材料对可见光的利用率低,光生电子与空穴易复合,导致降解有机污染物的效率不高,开发高效、稳定的半导体复合光催化材料,是当前光催化领域的研究热点。碳量子点(CQDs)是新型的纳米级荧光碳材料,可作为修饰剂与半导体材料复合,能够显著提高复合材料的光催化降解效率,极大地激发了研究者的兴趣。本文介绍了碳量子点与半导体光催化剂的复合方法,总结了近几年CQDs/半导体复合光催化材料降解有机染料、抗生素、止痛药、酚类化合物等有机污染物的应用成果。     

石墨烯复合金属离子掺杂纳米二氧化钛光催化材料的研究进展

对石墨烯复合金属离子掺杂纳米二氧化钛光催化材料在污染物治理、CO₂还原和资源化、H₂生产等方面的研究进展进行了论述。石墨烯复合金属离子掺杂纳米二氧化钛光催化材料相较于纳米二氧化钛,其禁带宽度变窄,提高了在可见光区的吸收性能,提高了光催化活性,提高了污染物降解率、CO₂还原和资源化的产率和H₂生产效率。     

纳米二氧化钛复合材料降解水中污染物的研究

对金属离子掺杂纳米二氧化钛复合光催化材料降低水中污染物的研究进展进行了论述；金属离子掺杂纳米二氧化钛复合光催化材料相较于纳米二氧化钛，其禁带宽度变窄，提高了在可见光区的吸收性能，提高了光催化活性，提高了污染物降解率。     

TiO_2光催化技术研究进展及展望

半导体二氧化钛已被广泛应用于各污染治理领域,成为降解有机污染物的一种重要手段。文章从TiO2光催化剂的制备方法、掺杂与改性、负载基材三个方面综述了TiO2光催化技术的使用现状和研究进展,总结了TiO2光催化体系降解有机污染物的研究方向。     

光催化剂改性及外场耦合光催化研究进展

介绍了光催化剂改性和外场耦合光催化技术研究进展.光催化刺改性主要围绕金属离子掺杂、非金属掺杂、半导体复合和表面修饰展开,光催化剂制备方法多样化将是今后的发展方向.揭示了超声波场,磁场、电场和微波场等外场耦合光催化反应机理,其中复合场耦合光催化技术和新型光催化反应器设计成为未来应用外场耦合光催化降解有机污染物的研究重点.     

Ni/Co共掺杂二氧化钛纳米片的可控制备及光催化性能研究

采用水热法合成掺杂不同金属元素的片状TiO₂纳米材料,对掺杂金属元素的纳米材料的光催化性质进行深入探讨,并对其光催化降解条件及对有机污染物甲基橙的光催化降解应用进行研究,进而选择最佳掺杂金属元素的TiO₂纳米材料作为光催化剂。结果表明,Ni/Co共掺杂二氧化钛纳米片的催化降解有机染料甲基橙效果最佳,能在短时间内对有机染料进行有效降解,在紫外光照下其降解效率约为92%。     

二氧化钛纳米管制备及其光催化降解有机物应用研究进展

介绍了近年国内外二氧化钛纳米管的几种制备方法,有水热合成法、模板法和阳极氧化法,叙述了二氧化钛纳米管光催化氧化技术在有机污染物降解方面的研究进展。认为今后的研究和发展方向为:优化二氧化钛纳米管光催化反应光谱可利用的范围,提高二氧化钛纳米管的催化活性,探索二氧化钛纳米管光催化氧化降解有机污染物中的优化条件,加强专门针对降解有机污染物的二氧化钛纳米管的研究,进一步的研究反应机理,加强对二氧化钛纳米管在各个领域应用的探索,并转化为实际工程应用。     

外场耦合光催化降解有机污染物研究进展

介绍了外场耦合光催化降解有机污染物的研究现状。围绕提高光催化过程的量子效率和能量利用率,加速光生载流子的界面迁移率,降低复合率等问题,通过比较超声场、磁场、电场、微波场和热场耦合光催化降解有机污染物的特点,指出了光催化降解有机污染物存在的问题和今后的研究重点。     

环境领域的二氧化钛基光催化剂负载和改性技术研究进展

在环境问题日益加剧的今天,二氧化钛基光催化剂因其具有优异的性质,是光催化领域中人们研究的热点。二氧化钛基光催化剂研究包括能源领域的光解水制氢、太阳能电池、水体内污染物的去除以及CO_2资源化利用等方面。本文综述了近年来国内外二氧化钛的负载和改性技术的研究进展。通过硅土类、聚合物类、玻璃类和碳材料等载体来负载二氧化钛,可有效解决其易流失、难回收和容易团聚的问题;以非金属掺杂、贵金属沉积、过渡金属离子掺杂、染料敏化和半导体材料复合等对二氧化钛进行改性研究,可有效减小二氧化钛半导体材料禁带宽度,能够有效降低电子和空穴复合的概率,增强二氧化钛基催化剂的可见光活性。并对未来的二氧化钛基光催化剂在环境中污水处理及大气有机污染物治理应用研究方面进行了展望。     

Photocatalytic properties of TiO2 modified with platinum and silver nanoparticles in the degradation of oxalic acid in aqueous solution

The commercially available TiO₂-catalyst (Degussa P25) was modified with nanosized platinum and silver particles by the photoreduction method to obtain different noble metal loading (0.5 and 1 wt.%). The characterization of the synthesized catalysts was carried out by the BET method, XPS, TEM and the adsorption of the model pollutant. The degradation of oxalic acid has been studied in aqueous solution photocatalyzed by band-gap-irradiated TiO₂, modified with nanosized platinum or silver particles. The photocatalytic activity of TiO₂, modified with noble metal, is approximately double that of the semiconducting support. The adsorption properties of the catalysts, as well as the noble metal content on the surface of the support, influence the efficiency of the photocatalytic process. The reaction rate of photocatalytic degradation of the oxalic acid follows a zero kinetic order according to the Langmuir–Hinshelwood model. The increase of the quantum yield of the photodestruction reaction of the studied model pollutant is due to the formation of Schottky barriers on the metal–semiconductor interface, which serve as efficient electron traps, preventing the electron–hole recombination.     

Research progress on modification strategy of g-C3N4 and g-C3N4/Ti3C2 heterojunction

Graphite phase carbon nitride (g-C₃N₄) is a kind of metal-free semiconductor material with a forbidden band width of about 2.7 eV and has visible light response capability. Attributed to its good thermal and chemical stability, adjustable morphology and chemical structure, it is widely used in the field of photocatalysis. However, due to its low specific surface area and wide band gap, its response range to visible light is narrow and the recombination rate of photogenerated carriers is high, resulting in a low photocatalytic efficiency, which can be effectively improved by modification. The two-dimensional material Ti₃C₂ has a narrower band gap compared with other semiconductor materials, and the heterogeneous junction between Ti₃C₂ and g-C₃N₄ is expected to obtain a wider range of visible light absorption and higher photocatalytic efficiency. This article reviews the modification methods of g-C₃N₄ including morphology control, doping and constructing heterojunctions, as well as the action mechanism, preparation methods and applications of g-C₃N₄/Ti₃C₂ heterojunction in photocatalytic hydrogen evolution, organics degradation and synthesis, etc.     

g-C3N4的改性策略以及g-C3N4/Ti3C2异质结研究进展

石墨相氮化碳（g-C₃N₄）禁带宽度约为2.7 eV,具有可见光响应能力。由于其良好的热和化学稳定性,且形貌和化学结构可调,在光催化领域应用广泛。但由于其带隙宽,对可见光响应范围窄,且光生载流子的复合率高,导致其光催化效率低,可通过改性来改善。本文综述了对g-C₃N₄形貌调控、掺杂和构建异质结等改性策略,以及g-C₃N₄/Ti₃C₂异质结的作用机理、制备方法和在光催化析氢、有机物降解及合成等领域的应用。     

g-C3N4制备方法及其光催化性能提升途径的研究进展

聚合物半导体g-C3N4因较窄带隙、稳定性高、成本低等特点而在污染物降解和清洁能源生产方面引起了广泛关注。但纯g-C3N4光催化剂电荷分离率低、电荷重组率高等缺点导致其光催化能力不理想,因此改善g-C3N4的光催化性能是目前光催化领域的研究热点。通过构造异质结、元素掺杂等改性手段制备的g-C3N4基光催化剂增强了对可见光的吸收,光催化能力强,拥有较好的工业应用前景。本工作首先简单介绍了g-C3N4基光催化剂的研究现状,其次概述了其制备方法的研究现状并介绍了几种制备g-C3N4工艺及特点,说明了应用不同制备工艺时应注意的问题。此外对其光催化性能提升途径的机理进行阐述,并且指明了发展方向,最后进行总结和展望。在后续研究中,若能有效结合材料科学与环境科学的优势,开发结构稳定和光催化性能优异的g-C3N4基光催化复合材料对提高其实际价值具有重要意义。     

铁酸铋光催化剂改性的研究进展

铁酸铋是一种钙钛矿型半导体光催化剂,因具有合适的光学带隙,良好的化学稳定性及可见光吸收性等特点而备受青睐。然而,铁酸铋的光生电子空穴对复合率高,载流子效率较低,导致其光催化活性较弱,限制了其实际应用。在概述铁酸铋结构和光催化机理的基础上,着重综述了贵金属沉积、半导体复合、金属离子掺杂等铁酸铋改性方法的作用机理与研究进展,探讨了铁酸铋光催化剂未来的研究方向。     

铁酸铋光催化剂改性的研究进展

铁酸铋是一种钙钛矿型半导体光催化剂,因具有合适的光学带隙、良好的化学稳定性及可见光吸收性等特点而备受青睐.然而,铁酸铋的光生电子-空穴对复合率高,载流子效率较低,导致其光催化活性较弱,限制了其实际应用.在概述铁酸铋结构和光催化机理的基础上,该文着重综述了贵金属沉积、半导体复合、金属离子掺杂等铁酸铋改性方法的作用机理与研究进展,探讨了铁酸铋光催化剂未来的发展方向.     

A review on mechanism,applications and influencing factors of carbon quantum dots based photocatalysis

CQDs (carbon quantum dots) have attracted a lot of attention in the field of photocatalysis due to its absorption of visible light, up-conversion luminescence, rich free groups on the surface and low cost. CQDs doped semiconductor can improve the photocatalytic reaction rate by the following three points: (1) adjust the band structure of photocatalyst; (2) facilitate the absorption of more visible light; (3) facilitate electron transfer and inhibits electron-hole recombination. In this review, the mechanism (photosensitizer, electron acceptor, up-conversion luminescence, etc.) and applications (photocatalytic degradation of organic pollutants, reduction of heavy metals, etc.) of CQDs in the field of photocatalysis are briefly introduced. Finally, the factors affecting the photocatalytic activity were summarized in order to adjust the reaction conditions and show high catalytic activity. It is hoped that this review can provide insights and inspiration for the development of CQDs in the field of photocatalysis.     

Investigation into Photocatalytic Degradation of Gaseous Benzene in a Circulated Photocatalytic Reactor (CPCR)

Due to the fact that suspended TiO₂ powder enjoys free contact with gaseous pollutant molecules in photocatalytic reactors, it can generally achieve better efficiency than immobilized TiO₂ catalysts. However, difficulties with the separation of this catalyst powder from treated pollutants and its re‐use often limit its application. Therefore, a circulated photocatalytic reactor (CPCR) was designed to enhance the performance of the photocatalytic degradation of gaseous benzene. TiO₂ film photocatalysts were prepared by the sol‐gel method at low temperatures and coated onto the inner wall of this reactor by a bonding agent composed of poly‐(2, 2‐dimethyl)‐acrylic ethylene ester emulsion in which TiO₂ powder was characterized by FTIR, TEM and SEM. In particular, the influences of initial concentration and gas flow rate of benzene on the degradation conversion, D_p, apparent reaction rate constants, k_r, initial degradation rate, r, and the deactivation and regeneration of catalyst in the CPCR, were investigated. The results indicated that the degradation conversion, apparent reaction rate constants and initial degradation rate were closely correlated to the initial concentration of benzene. To elucidate the factors governing the observations, the adsorption characteristics and kinetics of the photocatalytic degradation of benzene were analyzed using the Langmuir adsorption isotherm and Langmuir‐Hinshelwood kinetic model. It was found that the reaction kinetics were best described by a fixed pseudo‐first‐order kinetic equation of photocatalytic degradation of gaseous benzene in the CPCR.     

改性纳米二氧化钛可见光催化降解水体中五氯酚

采用共沉淀-浸渍法制备掺Fe的改性纳米TiO2光催化剂,以五氯酚(PCP)的光催化降解反应为模型,研究了不同光催化剂、不同光催化降解体系对水体中PCP降解效率。结果表明,适量Fe元素掺杂改性TiO2后,光催化剂为锐钛矿型,粒径变小,形貌规则,分散性能良好,且掺杂后可降低纳米TiO2光生电子-空穴对的复合几率,提升光催化剂对可见光子利用率。0.008%Fe-TiO2具有最佳的PCP可见光催化降解效率,降解率达90.3%,超声对光催化氧化降解水体PCP有良好协同作用。该降解反应体系简单、可直接利用可见光,成本低、便于推广。