疏水性可见光响应型纳米CuO/TiO2催化降解高浓度硝基苯

采用十二烷基硫酸钠（SDS）对纳米CuO/TiO₂光催化剂进行疏水改性,并在可见光的照射下,研究了疏水性CuO/TiO₂对硝基苯降解的影响因素。实验表明：SDS-CuO/TiO₂催化剂具备完整的锐钛矿和CuO晶体衍射峰;SDS负载量变化对催化剂的紫外可见吸收性能没有影响;催化剂表面的疏水位主要是长链烷基。各影响因素的最佳水平分别是：SDS负载量2.3 g•（2.5 g TiO₂）^-1,初始浓度400～500 mg•L^-1,催化剂用量0.2 g•L^-1,pH 9,H₂O₂添加量6 ml•L^-1。最佳条件下硝基苯2 h降解率为80％,4 h降解率为93％。     

硝基苯废水的TiO2光催化降解研究

以钛板负载TiO2光催化剂对水中的硝基苯的催化降解进行了研究,考察了催化反应时间、溶液的pH值等因素对光催化反应的影响.实验结果表明,在实验条件下,光催化降解硝基苯的最佳条件为pH=3,反应时间100 min.用H2O2 UV TiO2光催化反应体系处理低浓度的硝基苯样品效果更好一些.     

N修饰纳米TiO2可见光催化降解氮氧化物

为了充分利用可见光催化转化氮氧化物,采用碳酸铵作为N源,用浸渍的方法制备了掺N的纳米TiO2。XRD分析结果表明,修饰和煅烧过程没有改变TiO2的晶型;由X光电子能谱(XPS)可得,N在TiO2晶格中形成N—Ti—O键;催化剂的UV-Vis漫反射光谱显示,N修饰TiO2催化剂的吸收光谱发生了一定程度的红移,在可见光区有一定的吸收。N修饰TiO2催化在蓝光照射下对NO2有一定的转化。合适的N修饰量和煅烧温度对修饰过程非常重要,m[(NH4)2CO3]/m(TiO2)为0.20的混合物在600℃下煅烧1.0 h的催化剂在可见光下转化NO2的活性最高。     

改性活性炭负载TiO2光催化降解硝基苯

制备经铁改性的活性炭负载TiO2的光催化剂,以40 W紫外线灯为光源,对硝基苯的光降解反应进行了研究。探讨了经铁改性活性炭负载TiO2光催化剂的用量、降解的反应时间、硝基苯初始浓度、溶液pH、反应温度对反应的影响。结果表明,在紫外灯光照射下,以0.01－0.08 g该催化剂处理25 mL的10－100 mg/L硝基苯溶液,均有明显的降解效果,最佳的降解时间和pH分别为40 min和6.6。     

TiO2制备条件对硝基苯光催化降解效果的影响

以TiOSO4为原料,采取Sol—gel自蔓燃工艺制备了纳米TiO2,并用XRD、TEM测试技术对TiO2粉体进行了表征;以硝基苯为模拟污染物,通过正交试验研究了溶胶pH、煅烧温度、煅烧时间、Ti4 与柠檬酸的摩尔比四个因素对光催化活性的影响。结果表明:四个因素对硝基苯降解率的影响顺序为:温度>摩尔比>pH>时间,并确立了最优制备方案为pH=7、煅烧温度为600℃、煅烧时间为1.5h、摩尔比为1:2,可使硝基苯3h的降解率为61.5%。     

CuO/TiO2纳米纤维可见光催化CO2合成甲醇

以介孔SiO_2球为模板、TiCl4为前驱体,采用气相生长法制备了直径为8～10nm的TiO_2纳米纤维,然后采用浸渍法制备了具有异质结结构的CuO/TiO_2纳米纤维,在可见光照射下催化CO_2合成甲醇。通过SEM、TEM、XPS、UV-Vis、XRD、荧光光谱(PL)对催化剂进行了表征。结果表明:TiO_2纳米纤维较锐钛矿TiO_2纳米颗粒和商业TiO_2纳米颗粒(P25)荧光强度明显降低,光生电子-空穴对更加稳定。通过在TiO_2纳米纤维上负载CuO形成异质结结构后,进一步降低了催化剂的荧光强度,也增强了在可见光区的吸收。在300 W氙灯照射5 h进行光催化CO_2合成甲醇实验中,P25负载CuO后,催化合成甲醇产量为676μmol/g-cat,而负载了CuO的TiO_2纳米纤维,甲醇产量达1791μmol/g-cat,较CuO/P25提高了165%。     

TiO2／UV／O2和TiO2／UV／N2体系降解水中对氯硝基苯

以商用TiO2P25为催化剂,分别在TiO2/UV/O2和TiO2/UV/N2两种体系下进行降解对氯硝基苯(pCNB)试验.采用ESR对两种体系下光催化反应形成的.OH进行测定,利用LC-MS对两种体系下反应形成的中间产物进行了定性和定量分析,最后对pCNB降解过程中氯和硝基的存在形式进行了研究.结果表明:TiO2/UV/O2体系的催化降解效果要明显优于TiO2/UV/N2体系;两种反应体系都有.OH产生,并且TiO2/UV/O2体系产生的.OH的量多于TiO2/UV/N2体系产生的.OH的量;TiO2/UV/O2体系形成的中间产物的种类要多于TiO2/UV/N2体系形成的,苯环上的氢、氯、硝基均可被.OH取代形成对硝基酚(pNP)、5-氯-2-硝基酚(5-C-2-PN)等酚类物质;两种体系下均有Cl-和NO2-存在,其中Cl-生成势与pCNB的去除势一致,只有TiO2/UV/O2体系中存在NO3-.     

g-C3N4/TiO2复合材料的制备及可见光催化降解硝基苯

采用原位合成法在TiO₂纳米管上沉积g-C₃N₄对材料进行改性,通过改变尿素的质量浓度制备了一系列不同负载量的g-C₃N₄/TiO₂复合材料(0.2、0.3、0.4、0.5、0.6 g·L^-1 g-C₃N₄/TiO₂ NTs),然后在可见光条件下考察了g-C₃N₄/TiO₂复合材料光催化降解硝基苯的性能,并对材料做了相关的表征分析和自由基清除实验。结果表明：将g-C₃N₄负载到TiO₂纳米管上可以显著提高光催化活性,可能是由于g-C₃N₄和TiO₂之间形成了异质结,延长了载流子的寿命,阻碍了电子与空穴的复合,从而提升了复合材料的光催化活性。     

可见光响应纳米TiO2-ZnO光催化性能的研究

以太阳光为光源,TiO2-ZnO复合材料为光催化剂,在太阳光照射下,以有机染料模拟工业废水为处理对象,研究了自制纳米复合材料TiO2-ZnO的光催化活性,结果表明:在日光照射60 min后,有机染料的降解率、CODCr去除率均＞90%,复合材料TiO2-ZnO光催化活性高于纯TiO2的光催化活性,光催化反应符合一级动力学方程.     

可见光响应的Fe^3＋修饰纳米TiO2光催化降解氮氧化物研究

为了在光催化转化氮氧化物的反应中利用可见光,以Fe（NO3）·9H2O作为Fe^3＋源,采用浸渍的方法,制备了Fe^3＋修饰的纳米TiO2。经XRD分析表明,搀杂和煅烧过程没有改变TiO2的晶型。由XRD和XPS图谱可知,Fe^3＋在TiO2表面形成Ti—O—Fe键。催化剂的UV-Vis漫反射光谱显示,Fe^3＋修饰TiO2催化剂的吸收光谱发生了一定程度的红移,在可见光区有一定的吸收。Fe^3＋修饰TiO2催化在蓝光照射下对NOx有一定的转化而且在模拟自然光下NOx的转化效率也有所提高。合适的Fe^3＋修饰量对修饰过程非常重要,Fe^3＋/Ti^4＋摩尔比为0.2%并在600℃下煅烧1.0 h的催化剂在可见光下转化NOx的活性最高。     

Degradation of phenol in industrial wastewater over the F–Fe/TiO_2 photocatalysts under visible light illumination

F–Fe/TiO_2 composite photocatalyst was synthesized by a facile one-step hydrothermal method and then characterized by XRD, XPS and UV–Vis DRS. The catalyst of F–Fe/TiO_2 exhibited the highest photodegradation rate for phenol as compared with pure TiO_2, F/TiO_2, Fe/TiO_2, F0.38–Fe0.13–TiO_2 and Fe(III)/F-TiO_2 under visible light irradiation. The simulated conditions of industrial phenolic wastewater including initial phenol concentration,visible light intensity, p H and different anions were investigated in the presence of F–Fe/TiO_2 photocatalyst. In addition, as expected, the F–Fe/TiO_2 photocatalyst displayed excellent stability, showing a potential industrial application for the treatment of phenolic wastewater.     

Degradation of atrazine using metalloporphyrins supported on TiO2 under visible light irradiation

A combined solar photo-Fenton and biological treatment is proposed for the decontamination of a mixture of five commercial pesticides commonly used in intensive agriculture Vydate (10% Oxamyl), Metomur (20% Methomyl), Couraze (20% Imidacloprid), Ditimur-40 (40% Dimethoate) and Scala (40% Pyrimethanil). Photo-Fenton experiments were conducted in a solar pilot reactor consisting of four compound parabolic collectors in which the pesticide mixture was treated at an original dissolved organic carbon (DOC) concentration of 200 mg/L in the presence of Fe²⁺ or Fe³⁺ concentration of 5, 20 and 55 mg/L. Ferrous ions were marginally more active than ferric in terms of active ingredient degradation, which followed zero order kinetics, more so in the early reaction stages. Photo-Fenton was also far more effective (by at least two orders of magnitude) than the respective dark reaction under identical experimental conditions.Irradiation for 50–100 min (normalized at 30 W/m² light intensity) at 20 mg/L Fe²⁺ was able to completely eliminate the active ingredients, and reduce DOC by about 15–50% and COD by 40–70%, respectively. At these conditions, ecotoxicity to the marine bacteria V. fischeri was substantially lessened, while aerobic biodegradability in tests with activated sludge was enhanced.     

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。     

可见光响应的非金属离子掺杂二氧化钛的研究进展

TiO_2的宽禁带宽度[Eg=(3.0～3.2)eV]限制了其光催化特性的实际应用,非金属元素掺杂为提高TiO_2在可见光光催化活性提供了契机。介绍了非金属元素(氮、碳、硫、氟和硼)掺杂TiO_2的制备方法和可见光催化活性的研究进展,分析非金属元素对TiO_2可见光催化活性的诱导机理。制备工艺影响掺杂元素的化学态和含量,决定掺杂元素在TiO_2晶体微观状态。掺杂元素在TiO_2晶体微观状态与TiO_2可见光催化活性具有相关性,对未来的研究方向进行了展望。     

可见光下Cu2O/TiO2催化臭氧氧化头孢曲松钠性能研究

抗生素是治疗各种传染病的常用药物,但残留在水环境中的抗生素会对生态系统造成威胁。因此,探索去除水环境中抗生素的有效方法具有重要意义。由于光催化臭氧氧化技术可以高效降解和矿化水体中的污染物,该技术受到广泛关注。本工作通过浸渍-化学还原法制备Cu₂O/TiO₂复合材料并将其作为可见光催化臭氧氧化头孢曲松钠(CRO)的催化剂。利用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、比表面积分析仪(BET)和紫外-可见漫反射光谱仪(UV-Vis DRS)对Cu₂O/TiO₂形貌结构和光学性能进行表征,考察了Cu₂O/TiO₂配比、Cu₂O/TiO₂投加量、臭氧浓度、头孢曲松钠初始浓度、溶液初始pH值等因素对可见光催化臭氧氧化头孢曲松钠的影响。结果表明,Cu₂O对TiO₂的掺杂改性使材料孔容和平均孔径增大,能带宽度减小,...     

Fullerene modification CdSe/TiO2 and modification of photocatalytic activity under visible light

CdSe, CdSe-TiO₂, and CdSe-C₆₀/TiO₂ composites were prepared using sol–gel method, and their photocatalytic activity was evaluated by measuring the degradation of rhodamine B solutions under visible light. The surface area, surface structure, crystal phase, and elemental identification of these composites were characterized by nitrogen adsorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and UV-visible (vis) absorption spectrophotometry. XRD showed that the CdSe-C₆₀/TiO₂ composite contained a typical single and clear anatase phase. SEM of the CdSe-C₆₀/TiO₂ composites revealed a homogenous composition in the particles. EDX revealed the presence of C and Ti with strong Cd and Se peaks in the CdSe-C₆₀/TiO₂ composite. The degradation of dye was determined by UV–vis spectrophotometry. An increase in photocatalytic activity was observed and attributed to an increase in the photoabsorption effect by fullerene and the cooperative effect of the CdSe. The repeatability of photocatalytic activity was also tested in order to investigate the stability of C₆₀ and CdS-C₆₀/TiO₂ composites.     

Efficient hydrogen production by photocatalytic water-splitting using Pt-doped TiO2 hollow spheres under visible light

Pt doped TiO₂ hollow spheres (Pt/HS-TiO₂) are prepared by a sol–gel method and characterized by XRD, SEM, TEM and UV-visible absorption spectra. In addition, Pt/HS-TiO₂ is employed as the catalyst for photocatalytic hydrogen production from water splitting under visible light irradiation. The results show that Pt/HS-TiO₂ with hollow sphere structure presents excellent photocatalytic hydrogen evolution performance. The hydrogen generation rate can reach more than 1023.71 μmol h⁻¹ g⁻¹ at room temperature and no obvious deactivation is observed after 30 h irradiation. Furthermore, the reactively of Pt/HS-TiO₂ could be reproduced in the repeated cycle. Therefore, Pt/HS-TiO₂ is a promising photocatalyst to efficiently generate hydrogen under visible-light irradiation at room temperature.     

Graphene modified Nd/TiO2 photocatalyst for methyl orange degradation under visible light irradiation

A novel nanoscale GR–Nd/TiO₂ composite photocatalyst was synthesized by the hydrothermal method. Its crystal structure, surface morphology, chemical composition and optical properties were studied using XRD, TEM, and XPS, DRS and PL spectroscopy. It was found that graphene and neodymium modification shifts the absorption edge of TiO₂ to visible-light region. The results of photoluminescence (PL) emission spectra show that GR–Nd/TiO₂ composites possess better charge separation capability than do Nd/TiO₂ and pure TiO₂. The photocatalytic activity of prepared samples was investigated by degradation of methyl orange (MO) dye under visible light irradiation. The results show that the GR–Nd/TiO₂ composite can effectively photodegrade MO, showing an impressive photocatalytic activity enhancement over that of pure TiO₂. The enhanced photocatalytic activity of the composite catalyst might be attributed to the large adsorptivity of dyes, extended light absorption range and efficient charge separation due to Nd doping and graphene incorporation.     

One-step hydrothermal synthesis of N-doped TiO2/C nanocomposites with high visible light photocatalytic activity

N-doped TiO(2) nanoparticles modified with carbon (denoted N-TiO(2)/C) were successfully prepared by a facile one-pot hydrothermal treatment in the presence of L-lysine, which acts as a ligand to control the nanocrystal growth and as a source of nitrogen and carbon. As-prepared nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR) spectra, and N(2) adsorption-desorption analysis. The photocatalytic activities of the as-prepared photocatalysts were measured by the degradation of methyl orange (MO) under visible light irradiation at λ≥ 400 nm. The results show that N-TiO(2)/C nanocomposites increase absorption in the visible light region and exhibit a higher photocatalytic activity than pure TiO(2), commercial P25 and previously reported N-doped TiO(2) photocatalysts. We have demonstrated that the nitrogen was doped into the lattice and the carbon species were modified on the surface of the photocatalysts. N-doping narrows the band gap and C-modification enhances the visible light harvesting and accelerates the separation of the photo-generated electrons and holes. As a consequence, the photocatalytic activity is significantly improved. The molar ratio of L-lysine/TiCl(4) and the pH of the hydrothermal reaction solution are important factors affecting the photocatalytic activity of the N-TiO(2)/C; the optimum molar ratio of L-lysine/TiCl(4) is 8 and the optimum pH is ca. 4, at which the catalyst exhibits the highest reactivity. Our findings demonstrate that the as-obtained N-TiO(2)/C photocatalyst is a better and more promising candidate than well studied N-doped TiO(2) alternatives as visible light photocatalysts for potential applications in environmental purification.