二氧化钛-硫化镉/还原氧化石墨烯复合材料光催化降解废水中有机物的研究

采用溶剂热法制备出二氧化钛-硫化镉/还原氧化石墨烯(TiO_2-CdS/rGO)三元复合光催化材料,研究其对亚甲基蓝、罗丹明B的光催化降解效果.结果表明,TiO_2-CdS/rGO对亚甲基蓝、罗丹明B的光催化降解效果优于TiO_2-CdS的,催化效率得到明显提高,降解时间大大缩短.在可见光照射下,以TiO_2-CdS/rGO为光催化剂,当光反应时间为40min时,亚甲基蓝、罗丹明B的降解率可达100%.     

铁酸锌掺杂纳米二氧化钛的制备及其光催化活性

 以钛酸四丁酯和自制铁酸锌为原料,采用溶胶-凝胶法制备了未掺杂的TiO₂和掺杂不同量的ZnFe₂O₄/TiO₂纳米粉体,通过XRD、TEM对产物的晶体结构、晶粒大小、形貌进行了表征,通过对罗丹明B的光催化降解实验研究了ZnFe₂O₄的掺杂对TiO₂催化活性的影响.结果表明,产物为纳米微粒,ZnFe₂O₄的掺杂能加快TiO₂的晶型转变速度,减小TiO₂的粒径,提高TiO₂的光催化活性.     

Fe3O4@NiSiO3催化剂制备及其催化芬顿氧化降解染料性能研究

通过溶剂热法和溶胶凝胶法制备Fe₃O₄@NiSiO₃纳米催化剂,并利用TEM、XRD、VSM、BET进行表征。构建非均相芬顿氧化体系,由单因素实验得出在最佳降解条件为, pH值为5.5、催化剂投加量为1.00 g.L_-1、H₂O₂投加量为2.5%时,罗丹明B的降解率达95%以上。利用磁性分离催化剂并重复利用5次,罗丹明B降解率无明显降低,证明Fe₃O₄@NiSiO₃纳米催化剂重复利用性能良好。同时,考察了该催化剂对其它四种染料：酸性大红3R、孔雀石绿、甲基橙、亚甲基蓝的催化芬顿氧化降解性能。结果表明,孔雀石绿、罗丹明B、亚甲基蓝的降解率均达95%,但偶氮类染料降解率较低。通过对比实验进一步研究表明,Ni元素对芬顿反应起促进作用。     

CdS光化学修饰介孔TiO2及其增强的可见光催化活性

[目的]提高介孔TiO₂材料的光催化活性。[方法]采用蒸发诱导自组装法(EISA),以四氯化钛和钛酸丁酯为钛源,嵌段共聚物P123(EO₂₀PO₇₀EO₂₀)为模板剂,制备介孔TiO₂。用光化学修饰法将CdS掺进介孔TiO₂中,合成对可见光有较好响应的复合材料,并利用X射线衍射(XRD)、透射电镜(TEM)、原子吸收分光光度法(AAS)和光催化等手段对样品进行表征。[结果]XRD和TEM结果表明成功合成有序的六方介孔材料;AAS确定复合材料中Cd的含量为0.96mg/g;光催化于500 W氙灯下以2×10^-5mol/L次甲基蓝(MB)为模型污染物,结果显示CdS/TiO₂复合材料的可见光催化活性明显提高。[结论]光化学修饰法制备的介孔CdS/TiO₂复合材料可增强其可见光催化活性。     

LaVO4/TiO2在分解甲基橙中的光催化性能研究

光催化剂TiO₂在污水有机物降解中有着巨大优势,但由于对光的利用率过低,需要在TiO₂的基础上进行掺杂来改善其光催化性能。本研究利用稀土镧元素对TiO₂进行了掺杂分别制备了LaVO₄/TiO₂和La(NO₃)₃/TiO₂复合光催化剂,并将它们应用于甲基橙的光催化降解反应,证实了LaVO₄对TiO₂的光催化效果有较明显的增强作用。另外还研究了不同pH条件制备和不同掺杂比例的LaVO₄/TiO₂光催化效果,pH在10.56左右制备出的LaVO₄和掺杂比例为5%的LaVO₄制得的LaVO₄/TiO₂复合光催化剂效果较好。     

NaBH4还原改性TiO2(B)及光催化性能研究

以TiCl₄为原料,在（CH₂OH）₂溶液中通过一步水热法制备单斜相二氧化钛[TiO₂(B)]。使用不同质量含量NaBH₄对TiO₂(B)进行还原改性,调控其内含Ti³⁺的浓度,合成了含Ti³⁺的TiO₂(B)-NaBH₄X样品。采用X射线衍射仪（X-ray diffraction,XRD）、拉曼光谱仪（Raman spectroscopy）、紫外-可见漫反射光谱仪（UV-visible diffuse reflectance spectroscopy,UV-DRS）、X射线光电子能谱仪(X-ray photoelectron spectroscopy,XPS）对材料进行表征。改性后TiO₂(B)-NaBH₄X样品保持其原有晶体结构,并未发生相变,仅有结晶度的改变。原始TiO₂(B)禁带宽度为3.15 eV,通过改性,Ti³⁺的存在改变了禁带宽度,成功地将禁带宽度降低到2.82 eV,将吸光区域扩展到可见光区域。通过可见光光催化分解水制氢与可见光降解甲基橙试验,确立了TiO₂(B)-NaBH₄3样品有最好的可见光光催化活性,产氢速率达到0.58 μmol·h^-1·g^-1,6 h降解率达到40%。     

TiO2／丝光沸石光催化降解甲苯特性研究

将吸附材料丝光沸石与德国Degussa公司生产的P25型光催化材料TiO₂混合，光催化降解\r 空气中微量甲苯，发现掺杂材料中P25型TiO₂用量减少后降解甲苯性能没有明显改变。此外，探讨 了空气流速、反应器甲苯进口浓度、紫外光强和波长以及水蒸气浓度对混合材料光催化降解甲苯效 果的影响，为此类混合光催化材料的应用提供了实验基础．     

固定床微反应器中p-NiFe_2O_4/n-CdS光催化降解亚甲基蓝性能

用水热法制备系列p-NiFe_2O_4/n-CdS光催化剂,通过固定床微反应器中可见光催化降解亚甲基蓝对p-NiFe_2O_4/n-CdS的光催化活性进行评价,并对光催化活性提高的机制和反应条件对降解性能的影响进行分析。结果表明:p型和n型两种窄带隙半导体复合可提高光吸收率和光生电荷的分离效率,从而提高光催化活性。固定床微反应器中亚甲基蓝光催化降解过程符合一级动力学反应模型;与光催化剂表面吸附性能相比,光生电荷的分离效率是影响固定床微反应器中可见光催化降解亚甲基蓝性能的主要因素。在NiFe_2O_4的复合质量分数为0.14%、流速为0.4 mL/h、亚甲基蓝的初始质量浓度为10 mg/L、pH=6时,固定床微反应器中可见光催化降解亚甲基蓝的降解率最高。     

石墨烯/TiO_2复合材料光催化降解模拟染料废水的研究

采用石墨烯/TiO_2复合材料对染料废水进行光催化降解.研究染料废水初始pH值、初始浓度、催化剂的加入量、不同系列染料(罗丹明B(rhodamine B,Rh B)、亚甲基蓝(methylene blue,MB)、甲基橙(methyl orange,MO))对石墨烯/TiO_2光催化性能的影响,结果表明石墨烯/TiO_2光催化降解染料废水的最佳条件:溶液初始p H值为6,染料废水初始浓度为25 mg/L,石墨烯/Ti O2为3 g/L,且60 min内罗丹明B溶液完全脱色.     

铱钽涂层形稳阳极电极电解乙腈模拟废水

乙腈是一种脂肪族的急性剧毒有机污染物,不仅危害大而且来源广泛,众多行业产生的污水中都包含乙腈。为了找到一种适合的DSA阳极来高效率地降解乙腈,对四种不同材料的阳极电极(钌铱钛(Ti/TiO₂-IrO₂-RuO₂)、钌铱钛锡(Ti/TiO₂-IrO₂-RuO₂-SnO₂)、铱钽钛(Ti/TiO₂-Ta₂O₅-IrO₂)和铱钽钛锡(Ti/TiO₂-Ta₂O₅-IrO₂-SnO₂))分别降解乙腈模拟废水的产物进行了研究,通过国标法测定不同时间段降解产物的COD值,比较四种阳极电极对乙腈模拟废水降解效果的优劣,结果显示在降解2.5小时时涂层含有铱钽钛元素的电极对乙腈的降解效果最佳。并以此电极为代表优化降解乙腈模拟废水条件,得到最佳条件为：PH为6.60,浓度为每500ml水中含1.32ml乙腈,电压为4.10伏,在此条件下降解率可达到69.0367%。     

Photocatalytic property of TiO2 sensitized by different crystal phase CdS

TiO2 samples sensitized by different crystal phase CdS(CT) are synthesized by hydrothermal process at different reaction temperature. The samples are characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), and UV-Vis diffuse reflectance(UV-Vis). The XRD result reveals that the crystal phase of CdS is transformed from cubic phase to hexagonal phase with the increase of hydrothermal reaction temperature(120-160 ℃). The absorption edge of CT is extended from 498 nm to 546 nm. The photocatalytic degradation of rhodamin B(RhB) in aqueous solution is used to evaluate the photocatalytic activity of CT. With the increase of the preparation temperature, the photocatalytic activity of CT becomes stronger. The degradation rate of RhB by CdS/TiO2 at 160 ℃(CT-160 ℃)reaches 78%.     

铕掺杂TiO2粉末的制备及其可见光光催化性能研究

以钛酸四正丁酯为原料,采用水热法制备铕掺杂TiO2粉末,对铕掺杂TiO2粉末的可见光光催化性能进行研究,并通过XRD、SEM分析对其进行表征。结果表明,铕掺杂TiO2粉末没有改变晶相结构,铕掺杂后使TiO2粉末由不规则形状转变为实心球状,且提高了TiO2粉末的光催化性能。模拟太阳光实验发现,铕掺杂TiO2粉末可明显提高其可见光光催化的降解能力,当辐照度为500W/m2、时间为240min时,其降解率达到78%。     

A review of TiO<Subscript>2</Subscript> nanoparticles

Climate change and the consumption of non-renewable resources are considered as the greatest problems facing humankind.Because of this,photocatalysis research has been rapidly expanding.TiO2 nanoparticles have been extensively investigated for photocatalytic applications including the decomposition of organic compounds and production of H2 as a fuel using solar energy. This article reviews the structure and electronic properties of TiO2,compares TiO2 with other common semiconductors used for photocatalytic applications and clarifies the advantages of using TiO2 nanoparticles.TiO2 is considered close to an ideal semi- conductor for photocatalysis but possesses certain limitations such as poor absorption of visible radiation and rapid recombination of photogenerated electron/hole pairs.In this review article,various methods used to enhance the photocatalytic characteristics of TiO2 including dye sensitization,doping,coupling and capping are discussed.Environmental and energy applications of TiO2, including photocatalytic treatment of wastewater,pesticide degradation and water splitting to produce hydrogen have been summarized.     

Catalysis of organic pollutant photodegradation by metal phthalocyanines immobilized on TiO<Subscript>2</Subscript>@SiO<Subscript>2</Subscript>

A TiO2@SiO2 hybrid support was prepared by the sol-precipitation method using n-octylamine as a template.The photocatalyst manganese phthalocyanine tetrasulfonic acid (MnPcS) was immobilized on the support to form MnPcS-TiO2@SiO2.X-ray diffraction (XRD) and UV-Visible diffuse reflectance spectra (UV-Vis DRS) were employed to characterize the catalyst.The photocatalytic degradation of rhodamine B (RhB) and the catalytic oxidation of o-phenylenediamine (OPDA) under visible light irradiation were used as probe reactions.The mineralization efficiency and the degradation mechanism were evaluated using chemical oxygen demand (COD Cr) assays and electron spin resonance (ESR),respectively.RhB was efficiently degraded by immobilized MnPcS-TiO2@SiO2 under visible light irradiation.Complete decolorization of RhB occurred after 240 min of irradiation and 64.02% COD Cr removal occurred after 24 h of irradiation.ESR results indicated that the oxidation process was dominated by the hydroxyl radical (·OH) and superoxide radical (O-·2) generated in the system.     

Carboxyl-modified hierarchical wrinkled mesoporous silica supported TiO2 nanocomposite particles with excellent photocatalytic performances

Titanium dioxide (TiO₂) is a common photocatalyst for organic pollutants degradation. However, in practical application, the poor adsorption capacity of pure TiO₂ seriously impeded its efficiency in the degradation of organic molecules. In this work, a series of hierarchical wrinkle mesoporous silica supported TiO₂ nano-composite particles (TiO₂ @WMS-COOH) were successfully prepared. Thanks to their high surface areas, large pore volumes and mesoporous structures, these materials showed high adsorption capacity and excellent photocatalytic performance towards dye molecules, which is comparable to or even better than commercial catalyst P25. Moreover, their photocatalytic efficiency can be further enhanced by increasing the calcination temperature during preparation process. Therefore it can be concluded that the TiO₂ @WMS-COOH particles may find promising applications in the photodegradation of organic pollutants.     

Photocatalytic and electrochemical degradation of methylene blue by titanium dioxide

A photoanode structure for dye-sensitized solar cells has been applied into the photocatalytic/electro- chemical cooperative degradation of methylene blue solu- tions. The low eutectic point of titanium dioxide （TiO2） with a fluorine-doped tin dioxide （FTO） conductive layer results in a high reactivity of TiO2 for the photocatalytic process as well as a good electron transfer for the elec- trochemical process. The porous TiO2 layer maintains a large surface area for the degradations. Through the com- binational process, the degradation velocity was improved by - 36 %, compared to a pure photocatalytic process.     

Nb_2O_5/CdS纳米粒子的制备及其光催化性能研究

通过简单的沉淀法合成了Nb2O5/Cd S纳米粒子,利用XRD、TEM、XPS对其进行了表征,采用制备的Nb2O5/Cd S纳米粒子在可见光照射下对罗丹明B进行了降解实验.结果表明:负载在Nb2O5表面上的Cd S粒径大小较均一,约为35 nm,在可见光照射下,Cd S质量比为20%的Nb2O5/Cd S纳米粒子光催化活性最佳,可见光照射下3 h对罗丹明B降解率为98%,经过3次循环利用,发现其具有良好的光催化稳定性.     

Al掺杂TiO_2的制备及酸化处理对其光催化活性的影响

锐钛矿相TiO2的光催化活性高于金红石相。采用化学溶液分解法制备了Al掺杂锐钛矿TiO2,并用硝酸对其进行酸化处理。利用TG-DTA、XRD、FTIR、BET和UV-vis等手段对样品进行了表征,通过对甲基橙的降解分析了酸化处理对Al掺杂TiO2光催化活性的影响。结果表明:掺杂Al能有效抑制TiO2由锐钛矿向金红石转变。酸化处理因能增大Al掺杂TiO2的比表面积而使其光催化活性提高。Al/Ti掺杂比为1∶4的样品在酸化处理后具有的光催化活性最高,60min后对甲基橙的降解达到100%。