Inverse Opal Structure of Nitrogen-Doped Titanium Oxide with Enhanced Visible-Light Photocatalytic Activity

Nitrogen-doped titanium oxide inverse opal structure was synthesized to combine both chemical and physical modifications on n -TiO₂ by the polystyrene sphere self-assembly followed by a sol–gel process. Enhanced visible-light absorption and subsequently enhanced photodegradation efficiency were observed in this unique structure, which can be attributed to both nitrogen-doping effect and inverse opal structure effect. Our work suggests that the coupling of photonic band gap structure with photocatalytic materials is a promising approach to achieve maximum enhancement for various photocatalytic materials, especially for environmental applications and solar cell devices.     

Visible-Light-Induced Photocatalytic Inactivation of Bacteria by Composite Photocatalysts of Palladium Oxide and Nitrogen-Doped Titanium Oxide

Composite photocatalysts of palladium oxide and nitrogen-doped titanium oxide (PdO/TiON) were synthesized by a sol–gel process, as convenient forms of nanopowder or immobilized powder on nanofiber. The PdO/TiON catalysts were tested for visible-light-activated photocatalysis using different bacterial indicators, including gram-negative cells of Escherichia coli and Pseudomonas aeruginosa, and gram-positive cells of Staphylococcus aureus. Disinfection data indicated that PdO/TiON composite photocatalysts have a much better photocatalytic activity than either palladium-doped (PdO/TiO₂) or nitrogen-doped titanium oxide (TiON) under visible-light illumination. The roles of Pd and N were discussed in terms of the production and separation of the charge carriers under visible-light illumination. The photocatalytic activity was thus dependent on dopants and light intensity. Microscopic characterization demonstrated that visible-light photocatalysis on PdO/TiON caused drastic damage on the bacteria cell wall and the cell membrane.     

可见光响应型掺氮TiO2的研究进展

由于TiO2光催化剂的太阳能利用率低和量子效率低,光敏化、过渡金属和非金属掺杂、贵金属沉积和复合其他半导体等技术被用来改善其光催化性能,其中氮掺杂是一种有效方法。本文综述了掺氮TiO2的制备方法和其在污染治理方面的应用,并讨论了掺氮TiO2的发展趋势。     

Laser-Induced Silver Nanoparticles on Titanium Oxide for Photocatalytic Degradation of Methylene Blue

Silver nanoparticles doped on titanium oxide (TiO₂) were produced by laser-liquid interaction of silver nitrate (AgNO₃) in isopropanol. Characteristics of Ag/TiO₂ (Ag doped TiO₂) nanoparticles produced by the methods presented in this article were investigated by XRD, TEM, SEM, EDX, and UV-Vis. From the UV-Vis measurements, the absorption of visible light of the Ag/TiO₂ photocatalysts was improved (additional absorption at longer wavelength in visible light region) obviously. The photocatalytic efficiency of Ag/TiO₂ was tested by the degradation of methylene blue (MB) in aqueous solution. A maximum of 82.3% MB degradation is achieved by 2.0 wt% Ag/TiO₂ photocatalyst under 2 h illumination with a halogen lamp.     

纳米二氧化钛光催化降解苯酚水溶液

以P 25纳米TiO2 作为光催化剂,在环状光催化反应器中进行了苯酚水溶液的光催化降解性能研究。系统考察了溶液的pH、P 25用量、银掺杂量、苯酚的初始质量浓度等因子对苯酚溶液光催化降解过程的影响。结果表明,在pH=7时,苯酚水溶液降解率达97 4%,强酸和强碱条件均不利于苯酚的降解;质量浓度50mg/L的苯酚水溶液,P 25用量为50mg,UV辐照30min时降解率为95 6%;质量浓度100mg/L的苯酚水溶液,P 25用量为150mg,UV辐照60min时降解率为95 4%;银掺杂P 25增加了其光催化活性,用质量分数为10%的硝酸银水溶液掺杂制备的复合光催化剂,苯酚的降解率比未掺杂时增加16 5%。     

木素类模型物紫丁香醇TiO2光催化降解

在光催化反应器中,以紫外光 (功率11 W,波长253.7 nm)作光源,在TiO2悬浮体系中,对含有木素类模型物紫丁香醇的有机废水进行了光催化降解实验,并研究了其反应特性.实验结果表明,暗反应60 min后,紫丁香醇在TiO2催化剂表面达到吸附解吸平衡,吸附总量百分比基本相同,TiO2表面饱和吸附量是初始溶液中紫丁香醇质量的16.3%;当TiO2用量为0.4 g/L,溶液pH值为3以及连续曝气和搅拌条件下,由降解吸光度曲线可知,经该紫外光照射12 h,初始浓度40.5 mg/L的溶液去除率达52%,继续照射4 h,最终可达到完全降解.由降解吸光度曲线和化学特征功能团显色实验可初步推断,在一定的紫外光照射下,紫丁香醇支链上的一个甲氧基先与苯环发生断裂,生成了具有单甲氧基结构的中间体-愈创木酚.通过联立方程定量分析了降解过程中紫丁香醇和愈创木酚的浓度.     

富勒醇修饰氮掺杂二氧化钛复合材料及其光催化性能研究

本文采用四丁基氢氧化铵催化碱法制备富勒醇,并以富勒醇为原料,采用溶胶凝胶法制备富勒醇修饰氮掺杂二氧化钛光催化材料,对该复合材料的成分、结构等进行表征与分析,并研究复合材料的光催化还原CO₂的性能。结果表明,复合材料在可见光区的光吸收性能增强,表现出良好的室温可见光催化还原CO₂活性,其中CO平均生成速率达5.560 μmol·g^-1·h^-1,CH₄平均生成速率为0.789 μmol·g^-1·h^-1。分析认为,富勒醇复合与N掺杂有效提高了TiO₂的可见光催化活性。     

TiO2纳米管阵列光催化降解苯酚

采用电化学阳极氧化法在钛基体上制得了高度致密的、有序的、均匀的TiO2纳米管阵列。用SEM、XRD等对其表面形貌和结构晶型进行了表征和分析。以TiO2纳米管阵列为光催化剂对废水中典型的有机污染物——苯酚进行了光催化降解,考察了影响光催化降解速率的因素。结果表明,在紫外光照下,苯酚水溶液的pH=3、ρ(苯酚)=10.0 mg/L时,具有锐钛矿相结构的TiO2纳米管阵列的光催化效果最好,相同条件下与溶胶凝胶法制备的纳米TiO2颗粒膜的光催化降解速率进行对比,前者比后者提高了近一倍。     

New Method to Prepare Nitrogen-Doped Titanium Dioxide and Its Photocatalytic Activities Irradiated by Visible Light

A Ti-based metal organic compound is taken as the precursor to be decomposed in NH₃ flow at a certain temperature to prepare modified TiO₂ with high photocatalytic activity under visible-light irradiation. The processes of doping and crystallization of TiO₂ are conducted at the same time during the treatment in the NH₃ flow. This approach could efficiently dope N into anatase TiO₂ lattice. The prepared TiO₂ also has well-defined mesoporosity with a BET area of 217 m²/g.     

Photocatalytic Degradation of p-Cresol by Zinc Oxide under UV Irradiation

Photocatalytic degradation of p-cresol was carried out using ZnO under UV irradiation. The amount of photocatalyst, concentration of p-cresol and pH were studied as variables. The residual concentration and mineralization of p-cresol was monitored using a UV-visible spectrophotometer and total organic carbon (TOC) analyzer, respectively. The intermediates were detected by ultra high pressure liquid chromatography (UPLC). The highest photodegradation of p-cresol was observed at 2.5 g/L of ZnO and 100 ppm of p-cresol. P-cresol photocatalytic degradation was favorable in the pH range of 6-9. The detected intermediates were 4-hydroxy-benzaldehyde and 4-methyl-1,2-benzodiol. TOC studies show that 93% of total organic carbon was removed from solution during irradiation time. Reusability shows no significant reduction in photocatalytic performance in photodegrading p-cresol.     

ZnO/氧化石墨烯复合材料的制备及其可见光催化性能?

以均匀沉淀法制备纳米ZnO,并将其负载在氧化石墨烯(GO)上制得了ZnO/GO复合材料。XRD、TEM、UV、PL等证实在GO表面分散着颗粒均匀的ZnO纳米颗粒,GO与ZnO纳米颗粒之间存在电子转移效应,抑制ZnO中光生电子空穴对的复合,提高了ZnO的可见光催化性能;考察了复合材料在模拟太阳光条件下降解亚甲基蓝的光催化性能,当GO添加量为10%时,模拟太阳光照射90 min后,对亚甲基蓝的降解率达到97.2%,经过10次循环使用后降解率没有明显降低,复合材料的可见光催化活性明显优于纯的纳米ZnO,同时ZnO/GO复合材料对部分工业染料也有很好的降解活性。     

稀土Y3+掺杂TiO2光催化降解染料废水的研究

用溶胶-凝胶法制备了稀土Y3+掺杂TiO2,对其进行了XRD分析,以刚果红溶液为目标降解物研究了稀土Y3+掺杂TiO2的光催化性能。结果表明:同等实验条件下Y3+掺杂TiO2比纯TiO2的降解效果好。当稀土Y3+的掺杂量n(Y3+)∶n(TiO2)=0.5%(摩尔比)、焙烧温度600℃、刚果红溶液初始浓度20 mg/L、pH=3、催化剂用量为1.5 g/L时,其光催化性能最佳。反应1 h的降解率可达98.55%。     

二氧化钛和氧化锌的光催化活性(英)

通过二氧化钛和氧化锌的光催化作用研究,讨论了有机及无机表面处理对该作用的影响。与无机处理相比,有机表面处理对降低二氧化钛和氧化锌的光催化活性有很大影响,进而显著地减小了其在化妆品中的副作用,具有重要的意义。     

Solar‐Assisted Photocatalytic Degradation of Benzoic Acid Using Titanium Dioxide as a Photocatalyst

The photocatalytic degradation of benzoic acid using titanium dioxide (Degussa P‐25) as a photocatalyst has been studied. The effects of various anions, which are common in industrial wastewater, and of the initial pH were also studied. The effect of the presence of low concentration of cations was also studied. From the intermediates detected a photocatalytic degradation pathway for benzoic acid has been proposed.     

Visible-Light Photocatalytic Degradation of Aromatic Contaminants with Simultaneous H2 Generation: Comparison of 2,4-Dichlorophenoxyacetic Acid and 4-Chlorophenol

Aromatic contaminants, 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chlorophenol (4-CP), were photocatalytically degraded in aqueous solutions under visible light illumination. 2,4-D was degraded more rapidly with more amount of simultaneous hydrogen generation than 4-CP. This is due to their difference in oxidative potentials, hydrophobic effects, electrostatic interactions and chemisorptions on the photocatalyst 3%WO _x /TiO₂.     

氮掺杂纳米氧化铈的合成及其降解酸性橙7的研究

以硝酸亚铈和三乙醇胺为原料,采用溶剂热法制备了不同氮掺杂量的纳米CeO2粉末,并用X射线衍射仪、BET测试仪、透射电镜以及化学分析等测试手段对合成产物进行了表征.以酸性橙7为目标降解物,对合成产物的降解性能进行了测试.结果表明:氮元素成功掺杂进CeO2晶格中,并显著提高了CeO2的降解性能,当N∶Ce (mol.)=0.3时,可见光条件下CeO2对酸性橙7的降解率为93.9％,相同条件下未掺杂CeO2对酸性橙7的降解率仅为44.3％.     

人造沸石负载TiO_2光催化降解印染废水的研究

用溶胶-凝胶法制备了人造沸石负载TiO2的复合光催化剂,利用XRD对该催化剂进行了表征,并研究其对活性艳蓝降解率的影响。结果表明:光照时催化剂降解活性艳蓝的效果比无光照时要好。在一定的催化剂用量范围内,其降解率随催化剂用量的增大而增大,达到一定值后降解率变化不大;当活性艳蓝的浓度为100 mg/L、pH=5时,负载配比为1∶6的复合光催化剂,其粒度为60~80目、用量为1.5 g/L时,降解率可达96.3%。     

柠檬酸改性Bi2O3光催化材料性能的研究

以Bi（NO3）3溶液为原料,浓氨水为矿化剂,在柠檬酸掺杂量为1％-3％（质量分数）的条件下制备了纳米Bi2O3粉体。以样品对水中罗丹明B的光催化降解性能为评价指标,对样品的光催化性能进行了评价。研究结果表明：采用水热合成法制备的柠檬酸改性纳米Bi2O3粉体光催化降解水中罗丹明B的反应为表观零级反应。当柠檬酸的掺杂量为1．5％时,样品的光催化性能最优,继续增加掺杂量,样品光催化性能有所下降。紫外光条件下样品的光催化性能优于日光条件下。     

三氧化钨光催化体系降解亚甲基蓝及反应级数的探讨

三氧化钨是一种半导体光催化剂,可用于降解水中污染物。在用三氧化钨作为光催化剂处理亚甲基蓝模拟废水的反应中,通过单因素和正交实验,确定最佳处理条件为三氧化钨用量50mg、反应时间40min、H2O2用量4mL。并通过动力学研究,确定在不同三氧化钨光催化反应体系中的降解反应级数。     

TiO_2光催化降解甲醛影响因素的研究进展

在全面分析国内外近几年来TiO2光催化降解甲醛的研究成果基础上,从催化剂、紫外光、甲醛气体和反应条件四个方面归纳出了影响催化活性的主要因素。详细讨论了各种因素的影响情况,最后提出了推进甲醛光催化降解反应活性的建议。