不同酸催化剂对有机-钛柱撑蒙脱石复合材料光催化活性的影响

以钛酸丁酯为前驱体,分别采用醋酸和盐酸为溶胶-凝胶法制备TiO2溶胶的酸催化剂,将制备的溶胶分别加入经阳离子表面活性剂十六烷基三甲基溴化铵改性的浙江临安和内蒙古膨润土中,制备了有机-钛柱撑膨润土复合光催化剂,并对其进行XRD,SEM,BET表征.实验结果表明:钛阳离子经交换进入了膨润土层间,并以锐钛矿型的晶形存在,而且制备的复合光催化剂具有较好的层状结构,其比表面积均比相应的未经柱撑的膨润土的比表面积大.并且以甲基橙为目标污染物,考察了所制备的有机-钛柱撑膨润土复合光催化剂的吸附性能和光催化活性,发现两种方法所制备的复合光催化剂均具有较好的光催化活性.但是由于在醋酸介质中溶胶的水解速度较慢,可形成稳定均质的凝胶,因而形成的TiO2粒径相对较小,因此对于不同类型的膨润土,以醋酸为酸催化剂制备的复合光催化剂均比用盐酸为酸催化剂制备的复合光催化剂的催化活性好.     

介孔SO4^2-／TiO2固体超强酸的制备与表征

以工业硫酸钛液为原料，分步水解制得吸附硫酸根的介孔偏钛酸，焙烧得到介孔SO4^2-／TiO2固体超强酸。用Hammett指示刑法、XRD、BET和FI—IR等多种手段对催化剂进行了表征；以乙酸乙酯的合成为模型反应，考察了催化活性。结果表明所制备的SO4^2-／TiO2催化剂是介孔结构；随着焙烧温度的升高和SO4^2-含量的增加，其比表面积和酸强度都先增大后减小。最高酸强度H0=14．52，最大比表面积为192m^2／g；酸强度及硫含量与催化活性都有着密切联系。在500℃下焙烧，硫含量为2．7%时，催化活性最高。     

载Pt-TiO2纳米管阵列制备及其光电催化性能

采用阳极氧化法在纯钛箔表面制备TiO2纳米管,再用直流电沉积法在纳米管内沉积Pt,制备出载Pt-TiO2纳米管电极.并采用场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)对其进行表征.研究载Pt-TiO2纳米管阵列与TiO2纳米管阵列对有机磷农药敌敌畏(DDVP)的光电催化降解效果,并与光催化、电降解做了简单对比.结果表明:所制Pt-TiO2纳米管存在锐钛矿晶型TiO2,其饱合光电流比TiO2纳米管大.与单独光催化、电降解相比,载Pt-TiO2纳米管电极光电催化降解效果更显著.     

镧掺杂TiO2/膨润土复合光催化材料的制备及性能

以钠基膨润土为载体,钛酸丁酯和硝酸镧为原料,采用溶胶-凝胶法制备镧掺杂TiO2/膨润土复合光催化剂,采用X射线衍射(XRD)和红外光谱(IR)对复合催化剂进行了表征,在紫外光照射下,通过对TNT废水的光催化降解,考察其光催化活性。实验结果表明,掺杂镧与未掺杂镧的TiO2/膨润土复合光催化剂中TiO2主要以锐钛矿型存在;掺杂镧的TiO2/膨润土复合光催化剂的光催化性能明显优于未掺杂镧的TiO2/膨润土复合光催化剂,当镧的掺杂量为1%(原子分数),焙烧温度为500℃时,其光催化活性达到最佳效果。     

含铁柱撑膨润土光催化降解OrangeⅡ

制备了两种含铁柱撑膨润土(Fe—Al—Bent和Fe—Bent),用XRD、BET、TEM对它们进行了性能表征。以偶氮染料OrangeⅡ为目标降解物,考察了它们作为复相Fenton催化剂的光催化性能,以及溶液的pH、H2O2浓度、催化剂用量对OrangeⅡ降解的影响．并与相应的均相Fenton反应进行了比较。结果表明Fe—Al—Bent和Fe—Bent具有很高的比表面积(分别为194．2和114．6m^2／g),用Fe—Al—Bent或Fe—Bent作光催化剂的复相光助Fenton反应的催化性能明显优于相应的均相光助Fenton反应。此外复合铁铝柱撑膨润土(Fe-Al-Bent)比单一的铁柱撑膨润土(Fe-Bent)在反应过程中具有更低的铁离子溶出量,它们还具有分离简单、重复使用性好等特点。     

铍、氮共掺杂TiO2的制备及其可见光下光解水制氢性能研究

通过煅烧硫酸钛与氨水水解沉淀物制备氮掺杂TiO2(N-TiO2),用浸渍法制备了铍、氮共掺杂TiO2光催化剂(Be-N-TiO2).通过可见光光还原沉积法载铂,以可见光(λ≥420nm)光催化制氢为探针反应考察了催化剂的活性,发现当煅烧温度为300℃,Be2 的掺杂量为1.5%(原子分数)时,制备的Pt/Be-N-TiO2制H2活性最高.通过XRD、DRS、FT-IR等手段对掺杂催化剂进行了表征,N掺杂可在TiO2中形成O-Ti-N键,使其具有可见光吸收能力;掺入Be2 可以有效的分离光生电子和空穴,减少了两者的复合,同时能够消除由于氮掺杂引入的氧空位,使共掺杂催化剂相对于单一的N-TiO2具有较高的可见光制H2活性.     

CNT-TiO2复合物的制备及其乳液催化苯甲醇选择氧化

以CNTs为基质,钛酸异丙酯为钛源,采用水热法制备CNT-TiO2复合物。采用扫描电子显微镜和X射线衍射等技术手段研究CNT-TiO2复合物的形貌和晶型结构特征,通过光学显微镜等技术手段研究TiO2、CNT-TiO2固体纳米颗粒形成的乳液体系的特征。以苯甲醇选择氧化制备苯甲醛为探针反应,研究浸渍法所制负载型钌基TiO2、CNT-TiO2乳液催化剂的催化反应性能,催化剂载体的乳化能力与其催化性能之间的规律性关系。结果发现:CNT-TiO2复合物的乳化能力强于TiO2颗粒,易形成乳液体积大及乳滴分布均匀的乳液体系;负载型Ru/CNT-TiO2催化剂的催化活性高于Ru/TiO2;催化剂载体的乳化能力与其催化活性密切相关,载体的乳化能力越强催化活性越高;CNT-TiO2复合物在苯甲醇选择氧化反应体系中起到了催化剂载体和固体乳化剂的双重作用。     

铁柱撑膨润土及染料橙二的光催化降解

通过铁盐与膨润土浆液反应制备铁柱撑膨润土(Fe-Bent)催化剂,结合X射线衍射(XRD)、比表面孔隙分析(BET)和高分辨扫描电镜(TEM)对催化剂晶相、比表面积和粒度进行表征。表征结果证实其具有很高的比表面积,铁以高催化活性的α-Fe2O3存在于复相催化剂中。以橙二为目标污染物,考察了不同类型的催化剂、催化剂用量以及H2O2浓度对其降解的影响,并与均相Fenton反应进行了比较。结果表明：使用铁柱撑催化剂,复相的Fenton反应对橙二的降解性能高于均相Fenton反应,且其具有良好的重复使用性。     

水热法合成氧化镍-二氧化硅催化剂及其用于碳纳米管的制备

以硝酸镍和正硅酸乙酯为原料，制得Ni(OH)2／SiO2二元胶体，经水热晶化法和常压干燥法分别合成了纳米级氧化镍-二氧化硅复合粉体催化剂}用这两种催化剂在相同催化裂解条件下分别制得了多壁碳纳米管；采用XRD和TEM等测试手段对两种催化剂物相、形貌及由两种催化剂制得的碳纳米管形态、收率及纯度作了比较，结果表明：水热晶化法比常压干燥法合成的催化剂粉体颗粒粒径小(为10～20nm），分散性好，催化活性高，使得所制得的碳纳米管管径小(为10～16nm)、分布窄、纯度和收率都相对较高；同时对用不同水热反应温度合成的催化剂(物相不同)制备碳纳米管进行了研究。     

Al-Ce柱撑膨润土的制备研究

以内蒙某地的钙基膨润土为原料,对其进行特性分析、钠化改型,再以改型膨润土为基质,采用常规水相合成法制备了蒙脱石层间Al-Ce柱撑化合物。借助X射线衍射分析(XRD),氮气吸附及扫描电镜(SEM)等分析手段,考察了Al/Ce摩尔比、柱撑剂反应温度、柱撑反应时间和柱撑化合物洗涤次数对柱撑膨润土在层间距(d_(001))、比表面积(BET)等性能方面的影响行为。结果表明,当n(Al)∶n(Ce)=5∶1,柱撑剂反应温度40℃,柱撑反应时间5 h,柱撑膨润土洗涤5次时,500℃煅烧后Al-Ce柱撑膨润土的层间距稳定在1.847 nm,比表面积达307.2 m~2/g,具有较好的热稳定性,可作为高性能柱撑膨润土加以应用。     

Platinum-nanoparticle-modified TiO2 nanowires with enhanced photocatalytic property

Highly crystalline Pt nanoparticles with an average diameter of 5 nm were homogeneously modified on the surfaces of TiO(2) nanowires (Pt-TiO(2) NWs) by a simple hydrothermal and chemical reduction route. Photodegradation of methylene blue (MB) in the presence of Pt-TiO(2) NWs indicates that the photocatalytic activity of TiO(2) NWs can be greatly enhanced by Pt nanoparticle modification. The physical chemistry process and photocatalytic mechanism for Pt-TiO(2) NWs hybrids degrading MB were investigated and analyzed. The Pt attached on TiO(2) nanowires induces formation of a Schottky barrier between TiO(2) and Pt naonoparticles, leading to a fast transport of photogenerated electrons to Pt particles. Furthermore, Pt incoporation on TiO(2) surface can accelerate the transfer of electrons to dissolved oxygen molecules. Besides enhancing the electron-hole separation and charge transfer to dissolved oxygen, Pt may also serve as an effective catalyst in the oxidation of MB. However, a high Pt loading value does not mean a high photocatalytic activity. Higher content loaded Pt nanoparticles can absorb more incident photons which do not contribute to the photocatalytic efficiency. The highest photocatalytic activity for the Pt-TiO(2) nanohybrids on MB can be obtained at 1 at % Pt loading.     

H(2)O(2)-sensitized TiO(2)/SiO(2) composites with high photocatalytic activity under visible irradiation

TiO(2)/SiO(2) composite photocatalysts were prepared by depositing of TiO(2) onto nano-SiO(2) particles. X-ray diffraction (XRD), transmission electron micrograph (TEM), Raman spectrometer, UV-Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the properties of the synthesized TiO(2)/SiO(2) composites. These results indicated that the products without calcination were amorphous, and calcination could enhance the crystallinity of TiO(2). Increases in the amount of TiO(2) would decrease the dispersion in the composites. H(2)O(2)-sensitized TiO(2)/SiO(2) composite photocatalysts could absorb visible light at wavelength below 550 nm. The photocatalytic activity of as-prepared catalysts was characterized by methyl-orange degradation. The results showed the uncalcined composite photocatalysts with amorphous TiO(2) exhibited higher photocatalytic activity under visible light, and the activity of catalysts with TiO(2) content over 30% decreased with increasing of TiO(2) content. Increases in the calcination temperature and TiO(2) content promote the formation of bulk TiO(2) and result in a decrease in activity.     

Synthesis and photocatalytic property of SnO2/TiO2 nanotubes composites

SnO2/TiO2 nanotubes composite photocatalysts with different SnO2 contents were successfully synthesized by means of a simple solvothermal process. The synthesized products were characterized physically by X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM). The composite photocatalysts can not only make the target pollutant, methylene blue (MB), adsorbed at a high concentration level around the surface of the composites but also decrease the recombination rate of electron-hole pairs so as to achieve good photocatalytic performance. The effect of SnO2 contents on the photocatalytic activities of the composites was also investigated. The results showed that the SnO2/TiO2 nanotubes composite photocatalyst with 5 wt.% SnO2 loading had the highest photocatalytic efficiency.     

TiO_2/改性膨润土复合光催化材料的制备及其性能

本文采用无机和有机两种改性方法对钠基膨润土进行改性,在超声辅助下采用溶胶-凝胶法制备了TiO2/改性膨润土复合光催化材料。用X射线衍射(XRD)和红外光谱(IR)等测试技术对复合材料进行了表征,以TNT的吸附和降解为模型反应,考察了膨润土的改性对复合材料的吸附和光催化性能的影响。实验结果表明:无机改性的膨润土层间距减小,而有机改性膨润土的层间距增大;膨润土的改性提高了其对水中有机物的吸附性能,且能有效地抑制复合材料中TiO2晶粒尺寸,提高复合材料的光催化性能。     

Oxidation of triclosan by ferrate: reaction kinetics, products identification and toxicity evaluation

The Crystal Violet (CV) dye represented one of the major triphenylmethane dyes used in textile-processing and some other industrial processes. Various metals doped titanium dioxide (TiO(2)) photocatalysts have been studied intensively for the photodegradation of dye in wastewater treatment. In order to understand the mechanistic detail of the metal dosage on the activities enhancement of the TiO(2) based photocatalyst, this study investigated the CV photodegradation reactions under UV light irradiation using a Pt modified TiO(2) photocatalyst. The results showed that Pt-TiO(2) with 5.8% (W/W) Pt dosage yielded optimum photocatalytic activity. Also the effect of pH value on the CV degradation was well assessed for their product distributions. The degradation products and intermediates were separated and characterized by HPLC-ESI-MS and GC-MS techniques. The results indicated that both the N-de-methylation reaction and the oxidative cleavage reaction of conjugated chromophore structure occurred, but with significantly different intermediates distribution implying that Pt doped TiO(2) facilitate different degradation pathways compared to the P25-TiO(2) system.     

Pt负载型二氧化钛纳米管/纳米晶复合光催化剂的制备及其光催化性能

结合强吸附能力与高光催化活性的催化剂有望更有效地除去废水中的污染物. 以Degussa P25二氧化钛为原料, 采用水热法制备了二氧化钛纳米管(简称为TNTs), 将TNTs加入到溶有氯铂酸和柠檬酸(还原剂)的无水乙醇中, 在蒸汽相水解装置中通过一步法制备了Pt负载型二氧化钛纳米管/纳米晶复合光催化剂. 蒸汽相处理过程中, 部分纳米管转变为锐钛矿相TiO₂, 仍有部分以管的形式存在, 使纳米复合物保留了较高的吸附能力. 利用X射线衍射(XRD)、透射电子显微镜(TEM)、比表面及孔隙度分析仪等方法对产物进行了表征. 结果表明, 粒径约为4 nm的金属性Pt较好地分散在TNTs及由纳米管转变而来、晶粒尺寸约为8 nm的锐钛矿相TiO₂晶粒表面, 复合物保留了高于216 m²/g的比表面积. 光催化降解染料酸性红及亚甲基蓝的实验结果表明, 纯管有较好的吸附能力, 但是光催化性能非常低, 经120℃蒸气处理并负载贵金属Pt后光催化活性有了显著的提高.     

Preparation, characterization and activity evaluation of TiN/F-TiO2 photocatalyst

In this paper, F-TiO(2) and TiN/F-TiO(2) nanoparticle photocatalysts were prepared by ball milling. The photocatalysts were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), terephthalic acid photoluminescence probing technique (TA-PL), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflection spectroscopy (DRS). The photocatalytic activity of the photocatalysts was evaluated by photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The results showed that the photocatalytic activity of the F-TiO(2) was much higher than that of TiO(2), and the photocatalytic activity of the TiN/F-TiO(2) was much higher than that of TiO(2) and F-TiO(2) under UV light irradiation. The optimum percentage of doped TiN is 0.2 wt.%. Compared with pure TiO(2), the photoabsorption wavelength range of the TiN/F-TiO(2) and F-TiO(2) photocatalysts red shifts and improves the utilization of the total spectrum. The effect of ball milling time on the photocatalytic activity of the photocatalysts was also investigated. The optimum ball milling time is 12 h. The mechanisms of influence on the photocatalytic activity of the photocatalysts were also discussed.     

磁载核壳型TiO_2复合光催化剂的研究进展

TiO2是一种高效的光催化剂,为解决TiO2纳米颗粒从悬浮体系中分离回收难的问题,可将其包覆于磁性微球之外,借助于磁场的作用实现快速有效分离。简要介绍了磁载核壳型TiO2复合光催化剂的基本概念、分类及制备方法。根据磁载复合光催化剂的核壳之间是否包覆结合层,将其分为直接包覆磁载TiO2光催化剂和非直接包覆磁载TiO2光催化剂。磁载TiO2复合光催化剂的制备方法有溶胶-凝胶法、均匀沉淀法、微乳液法、原位生长法以及微波水热法等。还介绍了磁载核壳型TiO2复合光催化剂在水处理方面的应用,并且对其未来的发展前景进行了展望。     

Photocatalytic reduction of NO with NH3 using Si-doped TiO2 prepared by hydrothermal method

A series of Si-doped TiO2 (Si/TiO2) photocatalysts supported on woven glass fabric were prepared by hydrothermal method for photocatalytic reduction of NO with NH3. The photocatalytic activity tests were carried out in a continuous Pyrex reactor with the flow rate of 2000mL/min under UV irradiation (luminous flux: 1.1x10(4)lm, irradiated catalyst area: 160cm2). The photocatalysts were characterized by X-ray diffraction (XRD), BET, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectrophotometer, transmission electron microscopy (TEM), photoluminescence (PL) and temperature-programmed desorption (TPD). The experiment results showed that NO conversion on Si/TiO2 at 323K could exceed 60%, which was about 50% higher than that on Degussa P25 and pure TiO2. With the doping of Si, photocatalysts with smaller crystal size, larger surface area and larger pore volume were obtained. It was also found that Ti-O-Si bands were formed on the surface of Si/TiO2 and that the surface hydroxyl concentration was greatly increased. As a result, total acidity and NH3 chemisorption amount were enhanced for Si/TiO2 leading to its photocatalytic activity improvement.     

S、RE共掺杂TiO2的制备及其可见光分解水制氢性能

采用溶胶-凝胶法制备了系列稀土(La、Eu、Nd、Tb、Er)和硫共掺杂TiO2光催化剂RE/S/TiO2。通过紫外-可见(UV-Vis)漫反射、X射线衍射(XRD)对催化剂进行了表征。以EDTA为电子给体,考察了光催化剂在可见光照射下的制氢活性。研究结果表明,S/TiO2具有可见光活性,稀土掺杂进一步提高了S/TiO2可见光活性,其活性顺序依次为Eu/S/TiO2>La/S/TiO2>Nd/S/TiO2>Tb/S/TiO2>Er/S/TiO2。与纯TiO2和S/TiO2光催化剂相比,稀土掺杂使催化剂的粒径减小,晶格畸变应力增大,从而提高了催化剂可见光制氢活性。