TiO2/FACs与TiO2/Mullite复合材料的制备及其光催化性能

分别以粉煤灰漂珠(简记为FACs)与海胆状莫来石球(简记为Mullite)为基体,采用溶胶浸渍工艺制备了TiO₂/FACs与TiO₂/Mullite型复合材料。通过X射线衍射(XRD)、扫描电子显微镜(SEM)以及电子能谱(EDS)对制备的材料进行了表征。研究了TiO₂/FACs与TiO₂/Mullite型复合材料在紫外光照射下对罗丹明B(RhB)的光催化性能。结果表明：经500℃煅烧后形成的锐钛矿型TiO₂均成功负载到粉煤灰漂珠与莫来石晶体上,在粉煤灰漂珠表面覆盖了一层厚薄不均的纳米级别的TiO₂薄膜,而在莫来石晶体上则出现了大量细小的TiO₂颗粒;在降解染料时间为180 min,TiO₂/FACs与TiO₂/Mullite复合材料对罗丹明B染料的降解率分别为84.8%和96.4%,降解速率为0.01088min^-1和0.02885 min^-1。     

炭吸附La2O3/TiO2复合粉体的制备及其光催化性能研究

采用炭吸附共沉淀法制备了La₂O₃/Ti O₂催化剂,利用TG-DTG、XRD、TEM、UV-Vis等对催化剂进行表征,并考察了不同条件制备的La₂O₃/Ti O₂对可见光催化甲基橙降解效果的影响。结果表明,炭黑的加入可有效阻止粉体在制备、干燥及焙烧过程中的团聚和烧结;在600℃煅烧后得到的粉体结晶度高、颗粒分散均匀、颗粒粒径小。在可见光照射1 h后,炭吸附沉淀法制备的La2O3/Ti O₂对甲基橙的降解率高达92.25%,是普通沉淀法制得的La₂O₃/Ti O₂的3倍,光催化活性显著提高。     

纳米复合材料H6P2W18O62/TiO2-ZrO2（P123）的制备与微波辅助光催化降解甲基橙

在模板剂(C3H6O.C2H4O)x(P123)的作用下,采用溶胶-凝胶-程序升温溶剂热一步法制备了纳米复合材料H6P2W18O62/TiO2-ZrO2(P123)。通过傅里叶-红外光谱(FT-IR)、紫外-可见漫反射(UV-Vis/DRS)、X-射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜配合X-射线能量色散谱仪(SEM-EDS)和N2吸附-脱附等测试手段对其组成、结构和表面物理化学性质等进行了表征。结果表明,所合成的纳米复合材料H6P2W18O62/TiO2-ZrO2(P123)中多酸结构保持比较完整,复合材料具有锐钛矿晶型结构,属于介孔材料,模板剂P123使合成产物分布更加均匀。选取甲基橙(MO)作为模型分子,考察了该复合材料在微波辐射作用下的光催化性能。实验结果表明,该复合材料有较好的光催化活性,对甲基橙的降解效果明显高于TiO2、H6P2W18O62、H6P2W18O62/TiO2和H6P2W18O62/TiO2-ZrO2。     

不同后处理方法制备纳米复合材料Ag/TiO2-ZrO2及其微波辅助光催化甲基橙

采用P123(EO20PO70EO20)作模板剂,通过溶胶-凝胶-程序升温溶剂热一步法,并经煅烧和萃取两种不同的后处理方法制备了一系列具有光催化活性的纳米复合材料Ag/TiO2-ZrO2。经XRD、XPS、TEM、N2吸附-脱附测定测试手段对不同钛锆比例和不同后处理获得样品的组成、结构及形貌等进行了对比分析,获得了最佳光催化材料Ag/TiO2-ZrO2-C(3∶1)。该复合材料结晶度高、结构规整、呈四方体形、颗粒分布均匀,具有较均匀的孔结构,其银以单质形式存在,且均匀分散在TiO2-ZrO2表面。通过微波辅助光催化降解染料甲基橙的实验,对不同处理方法所获Ag/TiO2-ZrO2的光催化活性进行了探究。实验结果表明,通过煅烧后处理方法得到的催化剂具有最好光催化活性,在90 min内降解率高达94.0%,其活性高于市售P25、TiO2-ZrO2和Ag/TiO2-ZrO2-E(3∶1)。     

CQDs/TiO2二元复合材料的制备及光催化性能研究

以柠檬酸、硫脲、尿素等廉价易得的药品为原料,采用水热法制备了3种不同荧光性能的碳量子点CQDs(绿色荧光碳量子点GCQDs、蓝色荧光碳量子点BCQDs、红色荧光碳量子点RCQDs);同时采用溶胶-凝胶法制备了纳米TiO₂,然后通过物理法制备了3种二元复合光催化剂GCQDs/Ti O₂、BCQDs/TiO₂、RCQDs/TiO₂。采用FTIR、PL、XRD、BET等表征方法对产品进行了结构性能表征。通过紫外光谱分析,探究了Ti O₂和3种二元复合材料对次甲基蓝溶液的催化降解性能。光催化实验结果表明,纳米TiO₂在日光照射下10min对次甲基蓝的降解率为42.2%;GCQDs/TiO₂、BCQDs/TiO₂、RCQDs/TiO₂在日光照射下10min对次甲基蓝溶液的降解率分别为73.13%、46.82%、50.82%;3种二元复合材料的催化降解性能均优于纯TiO₂,其中GC...     

SiW12/聚苯胺/TiO2复合材料的光催化性能

以SiW12/PANI/TiO2为光催化剂。在紫外灯辐射下,研究了模拟染料废水甲基紫溶液的光催化降解的反应,考察了催化剂投加量、染料浓度、溶液的pH值对甲基紫降解率的影响。结果表明,甲基紫溶液光催化降解的最佳条件为:pH=5,SiW12/PANI/TiO2催化剂投加量为0.0125 g,浓度为5 mg/L,经30 W紫外灯照射90 min后,其降解率为90.69%。     

氮掺杂纳米TiO2光催化性能的研究

以钛酸丁酯和硝酸氮为主要原料,采用溶胶-凝胶法制备不同掺氮比的纳米TiO2(纳米N-TiO2)光催化剂。研究了不同的氮钛比、焙烧温度对氮掺杂纳米TiO2降解甲基橙溶液催化效果的影响。利用XRD、SEM方法对氮掺杂纳米TiO2的晶体结构及微观形貌进行了表征。结果表明:通过氮掺杂纳米TiO2,抑制了纳米TiO2晶粒的生长和晶型的转变,同时提高了TiO2的光催化活性。在紫外线灯的照射下,煅烧温度为500℃,N/Ti的原料配比为0.5%,制备的催化剂可达到最大的降解效果(为92.49%)。     

TiO2光催化薄膜的制备及其性能

在稀硫酸溶液中的阳极氧化钛箔,采用混合增长模型技术控制氧化膜的生长,制备了TiO2光催化薄膜.TiO2薄膜通过苯酚的光催化降解实验检验,具有较高的催化活性及很好的催化稳定性.实验结果表明阳极氧化法固定TiO2薄膜切实可行,不仅解决了TiO2微粒光催化过程催化剂微粒与水难分离的问题,而且阳极氧化制膜所需时间短(几秒到几分)、工艺简单,十分有利于工业化制备.     

仿生制备TiO2/ZnO复合材料及其光催化性能研究

利用结构仿生学的思想,以新鲜番薯叶为模板,利用浸渍-煅烧两步法成功制备出一系列叶片状的TiO₂/ZnO复合材料。利用SEM、XPS、XRD、BET等对复合材料进行表征。结果表明,复合材料由锐钛矿相TiO₂和纤锌矿相ZnO组成,保持了番薯叶片的多级复杂结构,具有介孔结构。光催化实验表明,TiO₂·6 h ZnO表现出最优的光催化性能。在室温下光照90 min, TiO₂·6 h ZnO对胭脂红水溶液的降解率可达到92.65%;动力学分析表明,TiO₂·x h ZnO复合材料对胭脂红溶液的降解反应均符合一级动力学模型。     

纳米TiO2粉体的制备及其光催化性能研究

以四氯化钛为原料,采用水解法制备了纳米TiO2粉体。用X射线衍射仪(XRD)、扫描电镜(SEM)对制备的粉体进行了表征,并研究了其对甲基橙的光催化降解性能。结果表明:产物为纯锐钛矿相纳米TiO2,一次粒度在100 nm以内;对甲基橙具有一定的催化降解作用,热处理温度为500℃时,产物的光催化活性较高。     

水基纳米TiO_2路径制备有序介孔TiO_2-SiO_2及其可见光催化性能

在多巴胺修饰的水基TiO_2纳米微粒(TiO_2NPs)悬浮液中,以正硅酸乙酯为硅源,十六烷基三甲基溴化铵为模板剂,分别采用碱性水热方法或酸性溶胶-凝胶方法,制备了有序介孔TiO_2-SiO_2(TiO_2NPs/MCM-41或TiO_2NPs/SBA-3)。采用XRD、TEM、ICP和N2吸附-脱附实验对样品进行表征。结果表明,制备的介孔TiO_2-SiO_2在TiO_2高负载质量分数(23.98%TiO_2NPs/MCM-41、17.27%TiO_2NPs/SBA-3)时,仍能保持长程有序的介孔氧化硅结构。TiO_2NPs随机地嵌入在有序介孔氧化硅孔道所组成的网络结构中。在可见光下催化甲基橙降解反应中,反应时间120 min时,在P25上甲基橙相对浓度降为57%,在TiO_2NPs/MCM-41上降为33%,而在TiO_2NPs/SBA-3上降为5.7%。     

硅藻土负载TiO_2光催化剂的制备及其应用

以钛酸丁酯为前驱体,多孔硅藻土为载体,采用溶胶-凝胶法制备硅藻土负载TiO_2光催化剂。通过SEM、XRD、FT-IR和N2吸附-脱附等对其形貌、表面组成及晶体结构进行表征。以1μg·m L-1氨氮废水溶液为目标降解物,太阳光为光源,研究硅藻土负载TiO_2催化剂的光催化活性。结果表明,采用500℃焙烧3 h的硅藻土负载TiO_2光催化剂,光照180 min,对氨氮的去除率为78.5%。     

石墨烯/TiO2的氯化改性及其新式自由基反应

成功制备了一系列石墨烯/TiO₂复合材料并分别氯化改性。以甲基橙和苯酚作为目标污染物,进行复合材料光催化降解活性实验;随后引入电化学和电子顺磁共振技术对该催化剂及其反应体系进行表征,推断其机理。结果表明,石墨烯具有极好的电子迁移能力,可以提高光生载流子的传递效率,进而增强TiO₂紫外催化性能。新型复合材料均表现出较高的光催化降解活性,甲基橙降解率由70%提升至100%,苯酚降解率由10%提升至100%。而表面氯化引入了新的活性基团,在光照条件下能够生成氯自由基,进而配合羟基、超氧,形成一种新的三自由基反应体系,使其氧化降解能力大幅提升。     

Z型Ag2CO3/BiOCl异质结光催化剂的制备及其可见光催化机理分析

通过溶剂热法制备BiOCl纳米片,共沉淀法制备Ag2 CO3和复合催化剂Ag2 CO3/BiOCl,研究各材料可见光催化降解罗丹明B的效果,确定Ag2 CO3与BiOCl的最佳配比,并通过表征分析复合材料的结构和异质结光催化降解机理.结果表明,当Ag2 CO3与BiOCl的质量比为50％时,Ag2 CO3/BiOCl异...     

Gd,B共掺杂改性TiO2纳米颗粒的可见光光催化活性

采用溶胶-凝胶法制备了Gd和B共掺杂的TiO2纳米颗粒,研究了TiO2纳米颗粒在可见光下的光催化活性。应用XRD、TEM和UV-Vis等手段对TiO2纳米颗粒的物相、粒径、形貌及光学性能进行了表征。结果表明,掺杂可以抑制TiO2晶粒增长,阻碍TiO2由锐钛矿相向金红石相的转变。紫外-可见吸收光谱显示,共掺杂纳米颗粒在可见光区吸收有较强提高,共掺杂离子以协同作用拓展TiO2光谱响应,使吸收带产生红移,提高光生载流子的分离效率。光催化降解实验表明,共掺杂TiO2纳米颗粒有很高的可见光光催化活性,以500℃热处理的共掺杂摩尔比为0.005 Gd和0.04 B的TiO2纳米颗粒光催化效果最好,在可见光下对甲基橙的降解率为98.9%。     

TiO2-SiO2复合材料应用研究进展

无机材料TiO₂和SiO₂因稳定性好、无毒害等性能得到广泛关注和应用,TiO₂-SiO₂复合材料因TiO₂和SiO₂组分的协同作用,表现出更加优异的性能。综述TiO₂-SiO₂复合材料在药物缓释、光催化、吸附、抗菌等相关应用领域中的研究进展,以期为其后续研究提供参考。     

Photocatalysis by polyoxometallates and TiO2: A comparative study

Polyoxometallates (POMs) as a homogeneous photocatalyst and TiO₂ as a heterogeneous photocatalyst seem to exhibit overall similar photocatalytic behavior. Both systems cause photodecomposition of a variety of organic pollutants via the formation and decay of several similar intermediates formed by OH addition (hydroxylation), dehalogenation, deamination, decarboxylation, etc. The final degradation products, for most organic substrates for both systems are CO₂, H₂O and inorganic anions. The similarity of behavior has been attributed to the formation of the common powerful oxidizing reagent, OH radical, from the reaction of the excited catalyst and water molecules.

On the other hand, lately, various laboratories have pointed out differences in reactivity and degradation mechanism between the two photocatalysts. The results are interesting and to a great extent contradictory.

This study compares the photodegradation of four substrates with diversified structures, namely, atrazine, fenitrothion, 4-chlorophenol (4-ClPh), and 2,4-dichlorophenoxyacetic acid (2,4-D) by both PW₁₂O₄₀³⁻ and TiO₂ and how their photodegradation is affected by the presence of strong OH radical scavengers, i.e., Br⁻ and isopropyl alcohol (i-prOH).

The results provide substantial evidence that the literature data on the apparent photooxidation mechanism of these two categories of photocatalysts is circumstantial, depending on substrate and the mode of investigation. Overall, though, the action of OH radicals relative to h⁺ appears to be more pronounced with PW₁₂O₄₀³⁻ than TiO₂.

With respect to thermal (dark) reaction of photoreduced catalysts, both systems can deliver their electrons to a variety of oxidants including metal ions. The advantages of POM relative to TiO₂ relates to the selective reduction precipitation of metal ions and to their unique ability to form metal nanoparticles in which POM serve both as reducing reagents and stabilizers.     

Purification/deodorization of indoor air and gaseous effluents by TiO2 photocatalysis

Our objective was to further assess the capabilities of TiO₂ to purify/deodorize indoor air and industrial gaseous effluents. Using a laboratory photoreactor including a lamp emitting around 365 nm and a TiO₂-coated fiber glass mesh, we first determined that the removal rate of three very different pollutants (CO, n-octane, pyridine) was 5–10 μmol per Wh consumed by the lamp for 50–2000 ppmv concentrations and 25–50 l h⁻¹ flow rates (dry air or O₂). We inferred that this order of magnitude allows, by use of a reasonable-size apparatus, the abatement of pollutants in constantly renewed indoor air, except CO and CH₄ that are too concentrated. Using a TiO₂ photocatalysis-based individual air purifier prototype, we showed, through distinctive analytical measurements, that the average concentrations of benzene, toluene and xylenes were indeed reduced by a factor of 2–3 in an ordinary non-airtight room. We also showed that O₃ addition in O₂ very markedly increases the mineralization percentage of n-octane, under otherwise identical conditions, in the laboratory photoreactor without photoexcitation of O₃; this property of O₃ can expand the application field of photocatalytic air purification in industry, at least in some cases.     

Features of the transformation of Hg by heterogeneous photocatalysis over TiO2

UV/TiO₂ photocatalysis of 0.5 mM mercuric aqueous solutions has been analyzed starting from Hg(NO₃)₂, Hg(ClO₄)₂ and HgCl₂ at different pH (3, 7 and 11) and in the presence or absence of oxygen. Profiles of Hg^II concentration with time were characterized by a relatively rapid initial conversion followed by a decrease or an arrest of the rate, the shape of profiles changing with the conditions. Conversions at 60 min and initial quantum efficiencies have been found dependent on the initial conditions and type of mercuric salt. The faster transformation took place at pH 11 for all salts. A good transformation yield is observed also for HgCl₂, which behaves differently to the other two salts, at pH 3 under nitrogen and pH 7 (N₂ or O₂). Inhibition by oxygen was observed in acid and neutral media but not at basic pH. When the conversion was 50% or more, pale or dark gray solids were deposited on the catalyst, identified as mixtures of Hg⁰, HgO or Hg₂Cl₂. A unique kinetic scheme could not be defined, which seemed to depend on the nature of the mercury salt, the ambient conditions and the type of deposit. Implications of the application of the technique to real systems are discussed.     

TiO2光催化降解亚硝酸钠的研究

采用溶胶-凝胶法制备了TiO2光催化剂,以紫外光照射下的光催化降解亚硝酸钠为模型反应,以盐酸萘乙二胺显色法测定样品的吸光度,进而得出亚硝酸钠的转化率,并采用BET、XRD和IR对催化剂进行了表征。结果表明,500℃焙烧的TiO2催化剂比表面积为42.5 m2/g,平均孔径为5.8 nm,热稳定性好。400℃焙烧2 h的TiO2尚存在一定量的无定形相TiO2,500℃焙烧的TiO2完全转变为锐钛矿型TiO2,700℃时完全转化为金红石相。本实验最佳的反应条件为:TiO2(500℃,2 h)催化剂0.2 g,100 mL 0.125μg/mL亚硝酸钠溶液中,紫外光降解150 min,亚硝酸钠的降解率为100%;添加适量浓度的H2O2溶液,可促进亚硝酸钠溶液的转化。