硅包覆钛白粉及其光催化性能研究

以六偏硫酸钠为分散剂,九水硅酸钠为硅包覆剂,采用液相沉积法在金红石型钛白粉表面包覆一层硅氧化物,研究了硅包覆量、浆液浓度、p H值对硅包覆钛白粉的光催化性能的影响。采用TEM,SEM-EDS表征钛白粉包覆后的表面形貌、元素组成。结果表明:最佳工艺条件下制备的硅包覆钛白粉经过紫外光催化反应180 min,甲基橙的残余率约为80%,仅降解了20%,相比于未包覆钛白粉光催化活性大大降低。     

锆硅包膜金红石型钛白粉工艺优化及性能

采用溶胶–凝胶法制备了锆硅包膜金红石型钛白粉。通过正交实验研究了浆液浓度、分散剂用量和Zr O2、Si O2两种包膜剂含量对锆硅包膜金红石型钛白粉的影响,得到了制备锆硅包膜金红石型钛白粉的优化工艺条件。采用Nano-ZS型粒度仪、扫描电子显微镜、透射电子显微镜和能谱仪、Fourier红外光谱仪等测试手段,考察锆硅包膜金红石型钛白粉的效果和包膜机理。结果表明:金红石型钛白粉表面包覆了两层均匀而致密的Zr O2膜和Si O2膜。包膜后金红石型钛白粉的失光率、吸油量和遮盖力都有所下降,白度值增加。同时,证实了这两层膜是以化学键Zr-O-Ti和Si-O-Zr的形式结合在金红石型钛白粉颗粒表面。     

锆铈包膜金红石型钛白粉制备工艺研究

采用正交试验法优化工艺条件制备了锆铈复合包膜的金红石型钛白粉,研究了浆液浓度、搅拌速度以及ZrO_2和CeO_2两种包膜剂用量对锆铈复合包膜金红石型钛白粉的影响。通过正交试验设计及方案验证,获得了表面包覆了连续、均匀致密的锆铈复合膜的金红石型钛白粉,其应用性能有明显提升。     

后处理工艺对氯化法金红石型钛白粉性能的影响研究

以氯化法金红石型钛白粉浆料为原料,通过制浆分散、湿法研磨、硅铝包覆等后处理工序制备出氯化法金红石型钛白粉成品,其包覆硅、铝质量分数分别达到3.039 7%、2.762 0%。讨论了粒径及粒径分布对产品性能的影响,确定湿法研磨30 min可将粒径控制在0.15~0.35μm范围,达到后续表面处理工序对原料粒径的要求。采用X射线荧光光谱仪和分光色差仪对产品进行性能分析,其性能达到国际知名牌号的水平。     

SiO2包覆TiO2复合纳米粒子的制备及防晒性能研究

通过溶胶-凝胶法在金红石型纳米二氧化钛（TiO₂）表面包覆二氧化硅（SiO₂）薄膜,对纳米TiO₂进行表面改性。通过优化聚乙烯吡咯烷酮（PVP）用量、硅钛比、氨水的用量确定最佳制备条件为:TiO₂用量为0.3 g,PVP用量为0.4 g,硅钛比为2∶1,氨水用量为5 m L,获得了粒径小,SiO₂包覆层薄,单分散性好的SiO₂-TiO₂复合纳米粒子。应用FT-IR,XRD,SEM,TEM和UV-vis等对改性前后的粒子进行表征。结果表明:红外光谱图中出现Si-O-Ti键的振动吸收峰,改性前后的纳米TiO₂均为金红石型,SEM及TEM显示改性后的粒子团聚现象减弱,其表面形成了约10 nm的SiO₂薄膜。经过表面改性,SiO₂成功包覆在纳米TiO₂表面,复合纳米粒子的光催化活性得到有效抑制,纳米TiO₂作为防晒剂的安全性大大提高。...     

金红石型纳米二氧化钛表面包覆的若干研究

对金红石型纳米TiO2进行表面处理是钛白粉工业化生产中必不可少的关键步骤,处理的方法和包覆的程度直接影响到产品的应用范围。介绍了金红石型纳米TiO2表面包覆的机理、包覆的方式以及对包覆效果进行表征的一些常用方法。     

CeO2-ZnO/KIT-6催化剂在光催化吸附脱硫中的应用

光催化吸附脱硫技术在油品脱硫领域引起了极大的关注,具有高光催化活性和有机硫化物吸附能力的双功能材料的开发是关键。首次合成了3D介孔二氧化铈-氧化锌/KIT-6（CeO₂-ZnO/KIT-6）催化剂,并应用于二苯并噻吩（DBT）的光催化吸附脱硫。通过X射线衍射（XRD）、氮气吸附-脱附和透射电子显微镜（TEM）等手段对催化剂进行表征,并研究了催化剂在光照下对DBT的转化性能。实验结果表明,在没有额外添加氧化剂（例如氧气、过氧化氢或有机氧化剂）的情况下,CeO₂-ZnO/KIT-6具有很好的光催化脱硫能力,当二氧化铈质量分数为10%、氧化锌质量分数为15%时,催化剂CeO₂-ZnO/KIT-6对DBT的转化率可达90%,最大吸附量（以硫计）为8.1 mg/g。无氧化剂体系对于燃料的后续处理非常有利,并且可以明显降低脱硫成本。     

聚酯树脂涂料用金红石型钛白粉的表面改性及性能研究

为提高金红石型钛白粉的在聚酯树脂涂料中的应用性能，采用湿法包膜的方式在二氧化钛表面构筑了三层结构对其进行表面改性，制备了改性钛白粉P-Zr-Al/TiO₂。采用X射线荧光光谱(XRF)、透射电镜(TEM)表征了改性钛白粉的结构与性质，并测试了粉体的颜料性质评价其包覆效果。结果表明：当选用六偏磷酸钠作为磷包膜剂以及锆-硫酸的锆包覆工艺时，金红石钛白粉具有较好的光学性质，L^*值为98.89、遮盖率为85.52%、吸油量为17.5 g/100 g。同时应用的聚酯树脂涂膜经过240 h曝晒雨淋的模拟环境后，失光率为47.3%，ΔE为0.84，具有较好的耐候性。     

表面处理锆铝包膜工艺探讨

表面处理工艺在硫酸法生产金红石型钛白粉中起到了举足轻重的作用,表面处理工艺的好坏直接影响金红石钛白粉的光学性质及颜料性能,本文研究了钛白粉生产中表面处理锆铝包膜的方法,通过实验的方法,考察了锆铝包膜的包膜量、包膜温度和包膜时间的控制对钛白粉成品质量的影响;同时考察了金红石成品各项指标及应用性能,结合生产实际,从而确定最优的生产条件。找出了生产金红石型钛白粉的一种表面处理锆铝包膜条件。     

有机改性钛白粉效果及对涂料性能影响

采用醇类有机剂对金红石型钛白粉进行有机表面改性，实验研究不同醇类改性剂对钛白粉改性效果。并评价改性钛白粉在涂料体系中分散性、遮盖力、光泽等影响。实验结果表明：采用改性钛白粉R3产品粉体指标、分散稳定性及涂料体系性能均较好。通过红外光谱表征，有机改性剂在钛白粉表面形成包覆。     

TiO2与SiO2掺杂对Al2O3相转变的研究

通过球磨混合法,制备TiO₂、SiO₂和TiO₂+SiO₂掺杂的Al₂O₃粉体,经不同温度煅烧后进行X射线衍射(XRD)测试,比较研究这三种掺杂对Al₂O₃粉体相转变温度的影响。研究结果表明,TiO₂、SiO₂掺杂对γ-Al₂O₃向α-Al₂O₃的相转变均有促进作用。在掺杂质量分数为0.5%的情况下,二者可分别使γ-Al₂O₃完全转变为α-Al₂O₃的温度降低100 ℃和125 ℃。而TiO₂+SiO₂复合掺杂对γ-Al₂O₃向α-Al₂O₃相转变的促进作用优于TiO₂、SiO₂单独掺杂。TiO₂、SiO₂的质量分数均为0.3%时,复合掺杂可使γ-Al₂O₃完全转变为α-Al₂O₃的温度降低150 ℃。此外,还对TiO₂、SiO₂和TiO₂+SiO₂掺杂促进Al₂O₃粉体相转变的机理作了简单分析。     

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。     

TiO2-SiO2 and V2O5/TiO2-SiO2 catalyst: Physico-chemical characteristics and catalytic behavior in selective catalytic reduction of NO by NH3

TiO₂-SiO₂ with various compositions prepared by the coprecipitation method and vanadia loaded on TiO₂-SiO₂ were investigated with respect to their physico-chemical characteristics and catalytic behavior in SCR of NO by NH₃ and in the undesired oxidation of SO₂ to SO₃, using BET, XRD, XPS, NH₃-TPD, acidity measurement by the titration method and activity test. TiO₂-SiO₂, compared with pure TiO₂, exhibits a remarkably stronger acidity, a higher BET surface area, a lower crystallinity of anatase titania and results in allowing a good thermal stability and a higher vanadia dispersion on the support up to high loadings of 15 wt% V₂O₅. The SCR activity and N₂ selectivity are found to be more excellent over vanadia loaded on TiO₂-SiO₂ with 10–20 mol% of SiO₂ than over that on pure TiO₂, and this is considered to be associated with highly dispersed vanadia on the supports and large amounts of NH₃ adsorbed on the catalysts. With increasing SiO₂ content, the remarkable activity decrease in the oxidation of SO₂ to SO₃, favorable for industrial SCR catalysts, was also observed, strongly depending on the existence of vanadium species of the oxidation state close to V⁴⁺ on TiO₂-SiO₂, while V⁵⁺ exists on TiO₂, according to XPS. It is concluded that vanadia loaded on Ti-rich TiO₂-SiO₂ with low SiO₂ content is suitable as SCR catalysts for sulfur-containing exhaust gases due to showing not only the excellent de-NO_x activity but also the low SO₂ oxidation performance.     

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%。     

Synthesis of nanosized TiO2/SiO2 particles in the microemulsion and their photocatalytic activity on the decomposition of p-nitrophenol

Nanosized pure TiO₂ particles were prepared by hydrolysis of TTIP in the sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles. TiO₂/SiO₂ nanoparticles were also prepared from TEOS as a silicon source and TTIP as a titanium source. These particles were characterized by TEM, XRD, FT-IR, BET, TGA and DTA. From thermal analysis and XRD analysis, the anatase structure of pure titania appeared in the 300–600 °C calcination temperature range and the rutile structure was showed above 700 °C. However, no rutile phase was observed for the TiO₂/SiO₂ particles up to 800 °C. The crystallite size decreased and the surface area of TiO₂/SiO₂ particles monotonically increased with an increase of the silica content. From FT-IR analysis, the band for Ti–O–Si vibration was observed and the band intensity for Si–O–Si vibration increased with an increase of the silica content. The micrographs of TEM showed that the TiO₂/SiO₂ nanoparticles had a spherical and a narrow size distribution. In addition, TiO₂/SiO₂ particles showed higher photocatalytic activity than pure TiO₂ and the TiO₂/SiO₂ (90/10) particles showed the highest activity on the photocatalytic decomposition of p-nitrophenol.     

Application of pulsed chemical vapor deposition on the SiO2-coated TiO2 production within a rotary reactor at room temperature

Pulsed chemical vapor deposition (P-CVD) is a promising technology for the surface modification of TiO₂ particles. For the scale-up application of P-CVD, a custom-designed rotary reactor and corresponding coating process at room temperature was developed in the present work. The obtained SiO₂-coated TiO₂ particles were characterized by various measures including high-resolution transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, etc. The results illustrated that the SiO₂ films with a thickness of (3.7 ±0.7) nm were successfully deposited onto the surface of TiO₂ particles. According to the dye degradation tests and acid solubility measurement, the deposited film can effectively inhibit the photocatalytic activity and enhance the weatherability of the TiO₂ particles. Zeta potential measurements showed that the SiO₂-coated TiO₂ is possible to be stably dispersed in the pH range of 6.9–11.6. The coating process made the whiteness of TiO₂ particles decreased slightly but still sufficient (97.3 ±0.1) for application. Furthermore, the properties of the TiO₂ particles coated by P-CVD were compared with the particles coated by traditional wet chemical deposition. It is shown that the P-CVD can produce thinner but denser films with better photoactivity suppression performance. The developed coating process within the rotary reactor was proved practically feasible and convenient for the scale-up production of SiO₂-coated TiO₂ via P-CVD.     

CeO2的形貌对CuO/CeO2催化剂CO2加氢制甲醇性能的影响

采用水热法制备CeO₂纳米颗粒（W-CeO₂）、CeO₂纳米片（S-CeO₂）、CeO₂纳米棒（B-CeO₂）及CeO₂纳米八面体（O-CeO₂）,用浸渍法负载相同质量分数的铜形成CuO/CeO₂催化剂。通过扫描电镜（SEM）、高分辨透射电子显微镜（TEM）、X射线衍射（XRD）、拉曼光谱（Raman）、自动吸附分析仪（BET）、H₂程序升温还原（H₂-TPR）、N₂O滴定等表征技术对催化剂进行表征,并在可控温控压的固定床石英管反应器中对催化剂的催化性能进行评价。研究了不同形貌CuO/CeO₂催化剂对CO₂加氢制备甲醇的影响;结果表明,CuO/CeO₂催化剂的催化活性存在明显的形貌依赖性,催化剂的暴露晶面、比表面积、表面碱性位点、表面氧缺陷的差异均会对CO₂转化率、甲醇选择性和产率产生影响。其中,不同形貌CeO₂优先暴露晶面的活性顺序为S-CeO₂（{100}+{110}）>W-CeO₂{100}>B-CeO₂{111}≈O-CeO₂{111},暴露晶面活性越高,催化剂表面氧缺陷越多,CuO-CeO₂间相互作用越强,则催化活性越好。当为CuO/S-CeO₂时,催化剂表面中碱性位点最多,催化剂比表面积为88.8m²/g,铜分散度为19.2%,CO₂转化率为6.56%,甲醇选择性和收率为96.3%和0.063g/(g_cat·h),催化活性最好,由活性评价试验得转化率由高到低依次为S-CeO₂>B-CeO₂>W-CeO₂>O-CeO₂,可知CeO₂形貌差异会决定CuO/CeO₂催化剂的物化性能和催化活性,从而提升对不同形貌CuO/CeO₂催化剂催化CO₂加氢制甲醇的基础认识。     

Influence of surface modified mixed metal oxide nanoparticles on the electrochemical and mechanical properties of polyurethane matrix

Newly synthesized functional nanoparticles, 3-amino-1,2,4-triazole (ATA)/SiO₂–TiO₂ were introduced to the polyurethane (PU) matrix. Electrochemical techniques were used to investigate the barrier properties of the synthesized PU–ATA/SiO₂–TiO₂ nanocomposite coated steel specimen. In natural seawater, electrochemical impedance spectroscopy experiments indicated outstanding protective behaviour for the PU–ATA/SiO₂–TiO₂ coated steel. The coating resistance (R_coat) of PU–ATA/SiO₂–TiO₂ was determined to be 2956.90 kΩ·cm^–2. The R_coat of the PU–ATA/SiO₂–TiO₂ nanocomposite coating was found to be over 50% higher than the PU coating. The current measured along the scratched surface of the PU–ATA/SiO₂–TiO₂ coating was found to be very low (1.65 nA). The enhanced ATA/SiO₂–TiO₂ nanoparticles inhibited the entry of electrolytes into the coating interface, as revealed by scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray diffraction analysis of the degradation products. Water contact angle testing validated the hydrophobic nature of the PU–ATA/SiO₂–TiO₂ coating (θ = 115.4°). When the concentration of ATA/SiO₂−TiO₂ nanoparticles was 2 wt %, dynamic mechanical analysis revealed better mechanical properties. Therefore, the newly synthesised PU–ATA/SiO₂–TiO₂ nanocomposite provided excellent barrier and mechanical properties due to the addition of ATA/SiO₂–TiO₂ nanoparticles to the polyurethane, which inhibited material degradation and aided in the prolongation of the coated steel’s life.     

Preparation and characterization of TiO2–SiO2 nano-composite thin films

TiO₂ nanocrystalline particles dispersed in SiO₂ have been prepared by the sol-gel method using titanium- and silicon-alkoxides as precursors. Nano-composite thin films were formed on the glass substrates by dip-coating technique and heat treated at temperatures up to 500 °C for 1 h. The size of the TiO₂ nanocrystalline particles in the TiO₂–SiO₂ solution ranged from 5 to 8 nm. The crystalline structure of TiO₂ powders was identified as the anatase phase. As the content of SiO₂ increased, the anatase phase tended to be stabilized to higher temperature. TEM results revealed the presence of spherical TiO₂ particles dispersed in a disk-shaped glassy matrix. Photocatalytic activity of the TiO₂–SiO₂ (1:1) thin films showed decomposition of 95% of methylene blue solution in 2 h and a contact angle of 10°. The photocatalytic decomposition of methylene blue increased and the contact angle decreased with the content of TiO₂ phase. TiO₂–SiO₂ with the molar ratio of 1:1 showed a reasonable combination of adhesion, film strength, and the photocatalytic activity.     

氧化铈-二氧化硅介孔材料制备及对铜离子的吸附性能

采用共沉淀法和沉淀浸渍法制备了纳米氧化铈-二氧化硅（CeO₂-SiO₂）介孔材料吸附剂,主要考察了其对水中铜离子（Cu²⁺）的吸附行为。通过X射线衍射（XRD）、扫描电镜（SEM）和氮吸附（BET）等手段对合成的介孔材料进行了性能表征,并通过静态吸附实验分析了溶液pH、溶液初始金属离子质量浓度、吸附剂用量、吸附时间等条件对介孔材料吸附Cu²⁺性能的影响。结果表明：共沉淀法制备的纳米CeO₂-SiO₂介孔材料对Cu²⁺的去除效果较沉淀浸渍法要好;当溶液pH=7.0时CeO₂-SiO₂介孔材料对Cu²⁺的吸附效果最好,20 min时基本达到吸附平衡;溶液初始Cu²⁺浓度增大Cu²⁺去除率降低,Cu²⁺累计吸附量增大;随着吸附剂用量增加Cu²⁺去除率增大,当CeO₂-SiO₂吸附剂用量为0.15 g/L时对Cu²⁺的去除率趋于稳定;CeO₂-SiO₂吸附剂对不同金属离子吸附性能由大到小的顺序为Cu²⁺、Fe²⁺、Mn²⁺,该吸附过程均符合准二级动力学模型。