Preparation of ZrO2-TiO2-CeO2 and Its Application in the Selective Catalytic Reduction of NO with NH3

TiO₂,ZrO₂-TiO₂,andZrO₂-TiO₂-CeO₂ were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), specific surface area measurements (BET), temperature programmed desorption (NH₃-TPD), oxygen storage capacity (OSC), and temperature programmed reduction (H₂-TPR). The results showed that ZrO₂-TiO₂-CeO₂ exhibited large number of surface strong acid, possessed some oxygen storage capacity, and strong redox property. The three materials were used as supports and the monolith catalysts were prepared with 1% (w) V₂O₅ and 9% (w)WO₃ for selective catalytic reduction (SCR) of NO with ammonia in the presence of excessive O₂, and the results of catalytic activity showed that the catalyst used ZrO₂-TiO₂-CeO₂ as support yielded nearly 100% NO conversion at 275 °C at a gas hourly space velocity (GHSV) of 10000 h⁻¹, and it had the best catalytic activity and showed great potential for practical application.     

Preparation and Characterisation of Nano-Structured WO<Subscript>3</Subscript>-TiO<Subscript>2</Subscript> Layers for Photoelectrochromic Devices

Nano-structured WO₃-TiO₂ layers were prepared by the sol-gel route. To obtain transparent, porous and crack free layers up to 0.8 μ m with a single dipping cycle a templating strategy was used. As a template three-dimensionally network based on organically modified silane was introduced to the WO₃ and TiO₂ sols. The WO₃ layers were dip-coated onto the conductive glass substrate (TCO) and the TiO₂ layers on the top of the WO₃ layer. The morphology and the structure of the layers were determined by Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive X-Ray Spectroscopy (EDXS), Auger and Infrared spectroscopy. SEM image of the WO₃-TiO₂ layer confirmed the nano-porosity of the layers and give the size of the particles of about 10 nm for TiO₂ and 30 nm for WO₃ layer. Further analysis indicated that the titanium sol penetrates the WO₃ layer. Particles in the WO₃ layer consist of a crystalline monoclinic WO₃ core surrounded by a 5–10 nm amorphous phase consisting of WO₃, TiO₂ and SiO₂. The WO₃-TiO₂ layers were used to assemble all solid state photoelectrochromic (PE) devices. Under 1 sun irradiation (1000 W/m²) the visible transmittance of the PE device changes from 62% to 1.6%. The colouring and bleaching processes last about 10 minutes.     

Li2O-TiO2-SiO2-P2O5和Li2O-TiO2-Al2O3-P2O5体系锂离子固体电解质的制备及性能研究

一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率…     

Selective catalytic reduction of NO with CO on Pt/W–Ce–Zr catalysts

Various Pt catalysts (Pt/ZrO₂, Pt/CeO₂, Pt/CeZrO, Pt/WO₃/ZrO₂ and Pt/WO₃/CeZrO) were prepared and characterized, and their catalytic reduction reactions of NO by CO, with or without the presence of excess oxygen, were investigated. The results of temperature-programmed experiments showed that CO could be easily oxidized over Pt/CeO₂ and Pt/CeZrO while the introduction of WO₃ into the catalyst (Pt/WO₃/CeZrO) inhibited the reduction of catalyst surface; NO could not dissociate over those catalysts in oxidized state but after CO reduction at a low temperature, NO dissociation took place only over Pt/CeO₂ and Pt/CeZrO catalysts. For NO + CO reaction, those easily reduced catalysts Pt/CeO₂ and Pt/CeZrO exhibited better catalytic performances, and NO could be rapidly converted below 350 °C. For the reaction with the presence of excess O₂, the NO conversions were significantly inhibited, but better NO conversions were obtained over the tungstate-contained catalysts when compared with Pt/CeO₂ and Pt/CeZrO. The higher activities of Pt/W–Ce–Zr catalysts were attributed to their high acidities.     

三维有序大孔Ag/ZrO2-TiO2：制备及紫外光催化降解染料和水杨酸性能

采用聚苯乙烯(PS)微球作为模板剂,经溶胶-凝胶及煅烧后处理的方法制备了三维有序大孔(3DOM)复合材料Ag/ZrO2-TiO2。通过FTIR、XRD、XPS、N2吸附-脱附和SEM-EDS等对其进行了表征。结果显示,经PS微球作用后的复合材料Ag/ZrO2-TiO2具有锐钛矿晶型结构,其Ag以单质形式存在。该复合材料的孔结构高度有序,属三维有序大孔,平均孔直径为120 nm,孔壁由紧密堆积的Ag/ZrO2-TiO2纳米晶粒组成,孔收缩率约为40%。该复合材料表现出较好的紫外光催化降解水杨酸和甲基橙等染料性能,其活性明显高于商用光催化剂(Degussa P-25)、Ag/ZrO2-TiO2和3DOM ZrO2-TiO2,在90 min内对甲基橙的降解率达80.1%。     

磁靶向纳米Fe3O4-TiO2复合物的制备及其对肝癌细胞的光催化杀伤效应

采用三种低温溶胶-凝胶法制备了具有不同Fe₃O₄掺杂量的磁靶向纳米Fe₃O₄-TiO₂复合物, 通过X射线衍射(XRD)、透射电镜(TEM)、傅里叶变换红外(FTIR)光谱、紫外-可见(UV-Vis)光谱、荧光光谱(FS)及磁性能分析等表征方法筛选出包覆均匀、分散性好、磁性能优异及光催化活性较高的纳米Fe₃O₄-TiO₂复合物. 以四甲基偶氮唑蓝(MTT)法检测肝癌细胞(HepG2)的存活率, 考察纳米Fe₃O₄-TiO₂复合物在外磁场作用下对HepG2 细胞的光催化杀伤效应. 结果表明: 采用方法三制备的5%(质量分数)Fe₃O₄-TiO₂复合物具备核-壳结构, 在混悬液中分散性较好, 平均粒径约为50 nm, 具有较强的光催化活性和良好的磁响应性, 同时将纳米TiO₂的光响应范围拓宽至444 nm; 在外磁场作用下, 紫外光和可见光激发纳米Fe₃O₄-TiO₂复合物对HepG2细胞的杀伤效应差异不大, 且均强于纳米TiO₂; 其杀伤效应在0-1.0 T范围内随着外磁场强度的增大而增强.     

Monolith Manganese-Based Catalyst Supported on ZrO2-TiO2 for NH3-SCR Reaction at Low Temperature

Monolith catalysts were prepared using TiO₂ and ZrO₂-TiO₂ as supports with MnO₂ as active component and Fe₂O₃ as promoter. The catalytic activities at low temperature and stability at high temperature for selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) in the presence of excessive O₂ were studied after the catalysts calcined at different temperatures. The catalysts were characterized by X-ray diffraction (XRD), specific surface area measurements (BET), oxygen storage capacity (OSC), and temperature programmed reduction (H₂-TPR). The results indicated that the catalyst supported on ZrO₂-TiO₂ had excellent stability at high temperature, and possessed high specific surface area and oxygen storage capacity, and had strong redox property. The results of the catalytic activities indicated that the monolith manganese-based catalyst using ZrO₂-TiO₂ as support had evidently improved the activity of NH₃-SCR reduction reaction at low temperature, and it showed great potential for practical application.     

吸附相反应技术制备MnOx/CeO2/SiO2催化剂及其低温选择性催化还原Nox

采用吸附相反应技术制备得到了MnO_x/CeO₂/SiO₂催化剂,通过X 射线衍射（XRD）、透射电子显微镜（TEM）、高分辨透射电子显微镜（HRTEM）、紫外激光拉曼（Raman）等手段对催化剂进行了表征. HRTEM分析表明活性组分MnO_x与CeO₂都均匀分布在载体SiO₂表面;XRD分析表明Mn₃O₄特征峰随着CeO₂含量的增加逐渐减小至完全消失,CeO₂的加入降低了MnO_x的结晶程度,增加了MnO_x的分散性;Raman光谱表明催化剂表面的Mn离子能够进入CeO₂晶格,激发出空穴氧,随着CeO₂负载量的增加,催化剂氧空穴浓度先升高后降低.以NH₃为还原剂,考评催化剂的NO_x低温选择性催化还原（SCR）性能,催化剂催化活性随CeO₂负载量增加先升高后降低,与催化剂氧空穴浓度变化规律一致,说明催化剂活性受氧空穴浓度影响,氧空穴浓度升高,催化剂催化活性升高.     

超细CeO2的微波辅助加热合成及其抛光性能

引言铈基抛光粉因具有发削能力强,抛光时间短、抛光精度高、操作环境清洁、比其他抛光粉的使用效果佳等优点,被人们称为抛光粉之王".     

Visible-light-driven photocatalyst of Bi2WO6 nanoparticles prepared via amorphous complex precursor and photocatalytic properties

The visible-light-driven photocatalyst Bi₂WO₆ nanoparticles have been prepared by calcining amorphous complex precursor at a relatively low temperature of above 450 ^oC. The effects of calcination temperature and time on the structures and properties of Bi₂WO₆ nanoparticles have been investigated in detail. The photocatalytic activity of the Bi₂WO₆ powders were evaluated by degradation of RhB molecules in water under visible light irradiation (λ>400 nm). The results showed that the particle size and grain size of Bi₂WO₆ increased with the calcination temperature and time. The photocatalytic activity of the best sample was about 8.8 times higher than that of the sample prepared by traditional solid state reaction and the photo-degradations was a zero-order reaction. The best route to enhance the photocatalytic activity of Bi₂WO₆ was to prepare the sample at a lower temperature for a longer time, due to the samples with better crystallization and smaller particle size.     

离子交换-双氧水氧化法制备纳米CeO2晶体

以99.995% Ce(NO₃)₃和强碱性阴离子交换树脂为原料，采用离子交换-双氧水氧化法合成制备出纳米CeO₂晶体。并就离子交换反应中的Ce³⁺浓度、树脂加入速度和离子交换温度及H₂O₂加入速度等条件对CeO₂粒径的影响进行了探讨，得出了离子交换-双氧水氧化法制备纳米CeO₂晶体的最佳工艺条件。FTIR、TEM分析表明，离子交换法无需对合成的Ce(OH)₃溶胶进行洗涤即可去除NO₃^-、CO₃^2-等阴离子杂质，并用H₂O₂将该溶胶氧化，经真空干燥可制得粒径分布均匀，平均晶粒尺寸约3 nm，高纯度的CeO₂粉体。     

合成方法对Rh/CeO2-ZrO2-La2O3催化剂的结构、表面性能及DeNOx活性的影响

用沉积沉淀法合成两种不同系列的CeO2-ZrO2-La2O3混合氧化物(ZrO2和La2O3沉积CeO2粒子(标记为A-x)以及CeO2和La2O3沉积ZrO2粒子(标记为B-x)),并用作Rh催化剂的载体。XRD、拉曼、TPR、XPS和O2脉冲等表征结果显示出不同的沉积顺序将导致不同的结构和氧化还原性能,且B-x具有更高的氧迁移性、储氧能力和表面Ce浓度。当其负载Rh后,Rh/B-x催化剂具有更高的NO和CO转化率及N2选择性,且Ce的最佳含量为50at%。这可能归因于Rh负载于富铈表面形成更多有利于NO分解的表面Ce3+活性位。     

Phase equilibria in the system FeVO4−Fe2WO6 in the solid state

A diagram of the phase equilibria established in the solid state in the system FeVO₄?Fe₂WO₆ was plotted on the basis of X-ray phase analysis and DTA. This system, one of the intersections of the three-component system Fe₂O₃?V₂O₅?WO₃, does not appear to be a real two-component system in the solid state.     

Bi2WO6/g-C3N4复合型催化剂的制备及其可见光光催化性能

利用溶剂热法,把Bi2WO6纳米颗粒植入g-C3N4层间和表面成功地制备了Bi2WO6/g-C3N4复合型光催化剂。通过XRD、SEM、TEM、BET和UV-Vis分别对样品的结构、组成、形貌、比表面积、光学性能进行了表征。结果表明,g-C3N4层状结构被部分剥离成碎片且与Bi2WO6纳米颗粒形成了复合物。Bi2WO6/g-C3N4复合型光催化剂与单一Bi2WO6相比不仅扩展了可见光的响应范围、增大了比表面还加速了光生电子与空穴的分离。结果表明,Bi2WO6的最佳负载量为60wt%时,复合型光催化剂具有最高的可见光催化活性且性能稳定、易回收。     

纳米Fe3O4-TiO2靶向光动力疗法对肝癌细胞的杀伤效应

光动力疗法(PDT)作为一种迅速发展的传统替代疗法,在抗癌治疗中显示出巨大的潜力.为增强靶向性和提高光催化杀伤效率,本研究设计了一种新型光敏剂Fe₃O₄-TiO₂磁性纳米粒.在不同外磁场下,考察其在可见光和紫外光激发下对肝癌细胞的杀伤效应.同时利用流式细胞术检测纳米Fe₃O₄-TiO₂对肝癌细胞凋亡率、细胞周期和线粒体膜电位的影响.根据纳米Fe₃O₄-TiO₂和肝癌细胞的作用方式探讨其抗癌机制.结果表明,可见光激发纳米Fe₃O₄-TiO₂可以杀伤癌细胞,且其杀伤效率与紫外光激发下无明显差别.此外,Fe₃O₄-TiO₂比TiO₂具有更高的细胞摄取率,从而使其具有更高的选择性和光催化杀伤效率.其作用机制是光催化纳米Fe₃O₄-TiO₂产生活性氧ROS抑制癌细胞,然后通过阻滞细胞周期G₀/G₁期,降低线粒体膜电位,线粒体去极化,最终诱导细胞凋亡.     

Bi2WO6/g-C3N4复合型催化剂的制备及其可见光光催化性能

利用溶剂热法, 把Bi₂WO₆纳米颗粒植入g-C₃N₄层间和表面成功地制备了Bi₂WO₆/g-C₃N₄复合型光催化剂。通过XRD、SEM、TEM、BET和UV-Vis分别对样品的结构、组成、形貌、比表面积、光学性能进行了表征。结果表明, g-C₃N₄层状结构被部分剥离成碎片且与Bi₂WO₆纳米颗粒形成了复合物。Bi₂WO₆/g-C₃N₄复合型光催化剂与单一Bi₂WO₆相比不仅扩展了可见光的响应范围、增大了比表面还加速了光生电子与空穴的分离。结果表明, Bi₂WO₆的最佳负载量为60wt%时, 复合型光催化剂具有最高的可见光催化活性且性能稳定、易回收。     

Structural models for intergrowth structures in the phase system Al2O3-TiO2

The phase system Al₂O₃-TiO₂ was investigated in the compositional range from 48:52 to 62:38 mol% Al₂O₃:TiO₂. The samples were prepared by melting the binary oxides in an arc-imaging furnace and the obtained samples were examined by powder X-ray diffraction. The recorded powder patterns could be interpreted in terms of intergrowth structures consisting of two basic building blocks, which were deduced from the known crystal structures of β-Al₂TiO₅ and Al₆Ti₂O₁₃. The structure of a new ordered compound with the formula Al₁₆Ti₅O₃₄ is proposed. The thermal stability was estimated from DTA and tempering experiments and showed that all prepared samples decompose at temperatures around 800 °C into the binary oxides corundum and titania.     

共沉淀法和模板法制备均匀负载CeO2/ SiO2的研究

CeO2是三效催化剂(简称TWC)中被广泛应用的涂层材料[1],其优良的储放氧能力(OSC)可以扩大TWC的工作窗口,并可以在与γ-Al2O3的相互作用中提高Al2O3的高温稳定性[2]。在高温下,CeO2会因晶粒迅速长大而失去储放氧能力。为了提高CeO2的高温抗烧结能力,以及进一步提高其氧化还原能力,大部分研究者选择了在CeO2晶格中掺入其他离子的方法,如:Zr4 、Pr3 、La3 等[3￣5],这些离子在CeO2晶格中引入了晶格缺陷,不但稳定了结构,而且提高了氧传输能力。SiO2具有很高的化学稳定性、高比表面及高热稳定性,是载体的理想选择。研究表明,CeO2负载…     

粉煤灰漂珠负载Bi2WO6复合材料的制备及光催化性能研究

以工业固体废弃物粉煤灰漂珠(fly ash cenospheres,FACs)为载体,采用水热法制备了新颖的漂珠负载Bi2WO6复合材料(Bi2WO6/FACs),通过X射线衍射(XRD),扫描电子显微镜(SEM),X-射线光电子能谱(XPS),和紫外-可见漫反射光谱(DRS)技术对其进行了表征。XRD数据显示了正交相Bi2WO6的特征衍射峰。DRS结果证实了引入FACs后Bi2WO6对可见光的吸收增强。在可见光的照射下,以亚甲基蓝溶液的光催化降解评价了Bi2WO6/FACs复合材料的光催化性能。结果表明:Bi2WO6/FACs的光催化性能优于纯Bi2WO6的,其一级反应速率常数(k)为后者的2.4倍。尤其是由于漂珠质轻中空的特性,Bi2WO6/FACS复合光催化剂可长时间漂浮于水面,既能充分吸收光能,又有利于催化剂的回收和重复利用。     

粉煤灰漂珠负载Bi2WO6复合材料的制备及光催化性能研究

以工业固体废弃物粉煤灰漂珠(fly ash cenospheres, FACs)为载体, 采用水热法制备了新颖的漂珠负载Bi₂WO₆复合材料(Bi₂WO₆/FACs), 通过X射线衍射(XRD), 扫描电子显微镜(SEM), X-射线光电子能谱(XPS), 和紫外-可见漫反射光谱(DRS)技术对其进行了表征。XRD数据显示了正交相Bi₂WO₆的特征衍射峰。DRS结果证实了引入FACs后Bi₂WO₆对可见光的吸收增强。在可见光的照射下, 以亚甲基蓝溶液的光催化降解评价了Bi₂WO₆/FACs复合材料的光催化性能。结果表明：Bi₂WO₆/FACs的光催化性能优于纯Bi₂WO₆的, 其一级反应速率常数(k)为后者的2.4倍。尤其是由于漂珠质轻中空的特性, Bi₂WO₆/FACS复合光催化剂可长时间漂浮于水面, 既能充分吸收光能, 又有利于催化剂的回收和重复利用。