Grain Size and Wettability of TiO_2/SiO_2 Photocatalytic Composite Thin Filing

1 IntroductionTransparent super-hydrophilic self-cleaningTiO, thin films on glass substrates have highpotentialities for practical aPPlications such asmirrors, window glasses, windshields of automobiles, etc. The super-hydrophilic property ofthe surface allows water to spread completelyacross the surface rather than to remain asdroplets, Which malles the surface anti-foggingand easily washing. Recently, there are some research papers abollt the super-hydrOPhilic prOPerty of TiO, coating fi…     

玻璃基TiO_2-SiO_2/SiO_2增透膜的溶胶-凝胶法制备和表征

采用溶胶-凝胶工艺,用提拉法在普通玻璃上制备TiO2-SiO2/SiO2复合增透膜。用紫外-可见光谱(UV-Vis)测试膜层的透射率,计算复合膜层的光学常数、折射率和膜层的厚度;用扫描电镜(SEM)观察膜层的表面形貌;研究TiO2-SiO2的比例以及热处理工艺对复合膜光学常数的影响。结果表明:溶胶的稳定性是整个工艺的关键与基础,溶胶中乙醇含量、陈化时间以及热处理制度会对膜层的折射率和厚度造成影响,从而导致整个复合膜的透过率变化。通过优化工艺,制备出在可见光范围最大透过率>98%、平均透过率约为95%的高增透膜,并对得到的结果进行详细地讨论。     

Ag/TiO_2纳米复合材料的制备及结构研究

首先采用化学氧化在块体Ti表面制备出多孔纳米TiO2,随后通过高能离子束轰击实现Ag纳米粒子在TiO2表面的有效固定,最终在Ti表面制备出Ag/TiO2纳米复合材料。采用XRD、SEM及TEM手段对其进行了结构表征。结果表明,化学氧化法可制备出多孔纳米TiO2,其晶粒尺寸为10 nm左右;通过调节高能Ar离子束轰击的时间,可对TiO2晶粒尺寸进行小范围有效控制。     

High photocatalytic activity of Cu_2O/TiO_2/Pt composite films prepared by magnetron sputtering

Cu_2O/TiO_2/Pt three-layer films were deposited on glass substrates using magnetron sputtering method.The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), ultravioletvisible spectroscopy(UV-Vis) and photoluminescence spectroscopy(PL). The photocatalytic activity of the samples was evaluated by the photocatalytic degradation of methyl orange(MO) aqueous solution under visible light irradiation. The results indicate that the Cu_2O/TiO_2/Pt composite films are made up of three layers which are Pt layer,anatase-TiO_2 layer and Cu_2O layer from bottom to top. The surface of the films is even and composed of regular-shaped spherical particles. The photocatalytic activity of the Cu_2O/TiO_2/Pt three-layer film is much higher than that of the Cu_2O/TiO_2 double-layer film. Such enhancement is ascribed to the presence of Pt layer, which further inhibits the photogenerated electron-hole recombination, prolongs the lifetime of the photogenerated carriers, increases the quantum efficiency and hence improves the photocatalytic activity of the film effectively.     

Al掺杂TiO2介孔材料的合成、表征和光催化性能

以钛酸四丁酯为钛源、十八水硫酸铝为铝源、三乙醇胺为模板剂,采用研磨-溶胶技术合成了Al掺杂的TiO2介孔材料,并利用XRD、EDS、TEM、BET、UV-vis和IR等手段表征了材料的结构、形貌、比表面积、孔径分布及光学性能.结果表明:Al掺杂能够减小TiO2光催化剂的粒径,提高介孔TiO2的热稳定性;Al掺杂TiO2介孔材料的平均孔径为4.5 nm,比表面积达到110.2 m2/g;相比商用P25和介孔TiO2,Al掺杂介孔TiO2的吸收边发生红移,对初始浓度为20 mg/L的甲基橙进行催化降解1h后,其降解率达到92.5％.     

Adsorption and photocatalytic degradation of phenol over TiO_2/ACF

1　INTRODUCTIONToday ,waterpollutioncausedbyhazardousor ganicchemicalsusedinindustryandagricultureisaveryseriousproblem ,thedeeptreatmentandreuseofwastewaterisveryindispensable[1] .Titaniumdioxideheterogeneousphotocatalysiscandegrademostofor ganicpollutantscompletelyintoCO2 ,H2 Oandinor ganicacid ,andhasshowntremendouspotentialityinthetreatmentofwastewater[2 ] .TiO2 powderhasbeenthemostwidelyusedphotocatalystinthephoto catalyticprocessduetoitsstablechemicalproperties ,easyaccessandcheapc…     

铁酸钴纤维负载银/氯化银纳米粒子的合成及其对甲基橙的光催化降解

通过温和的湿化学合成法将Ag/AgCl纳米粒子固载于CoFe₂O₄纤维表面,固载银/氯化银纳米粒子的量可控。利用X射线衍射,扫描电子显微镜和电子显微镜等技术对制备的Ag/AgCl@CoFe₂O₄组成、形貌等进行了表征。以甲基橙的降解脱色为模型反应,考察了Ag/AgCl纳米粒子的不同负载量对催化性能的影响。实验结果表明：AAC-4型固载纤维光催化剂展示出比其它类型固载光催化剂以及单纯Ag/AgCl纳米粒子更高的光催化性能,可使甲基橙溶液60min的脱色率达98.2%,且Ag/AgCl纳米粒子在CoFe₂O₄纤维表面的固载 促进了光催化剂催化效率和催化稳定性的提升。     

SiO_2添加量对TiO_2薄膜表面特征及亲水性的影响

采用溶胶凝胶法在载玻片表面制备了均匀透明的TiO2/SiO2超亲水性薄膜。利用XRD、红外光谱(IR)和分光光度计,研究了SiO2添加量对薄膜微结构、透光率、亲水性的影响。结果表明:添加SiO2后,薄膜中TiO2晶粒尺寸变小;在薄膜中,TiO2和SiO2分别单独形成颗粒,但有部分Ti—O—Si键形成,存在部分复合氧化物;由于取代反应,复合氧化物中表面形成Lewis酸,薄膜表面吸附的羟基含量增多且稳定,可提高TiO2薄膜的超亲水特性,其超亲水性状态在暗处可保持很长时间;SiO2添加量为40%时的薄膜亲水性最好。     

微弧氧化法原位生长TiO_2光催化薄膜及其复合技术

介绍了利用微弧氧化技术制备TiO2光催化薄膜的工艺过程、形成机理、影响因素,以及膜层结构与性能之间的关系等。提出在微弧氧化工艺制备TiO2光催化薄膜的过程中,通过复合半导体、金属掺杂和非金属掺杂,可以有效地提高其光催化性能。     

电溶出铝土矿碱液矿浆时硅钛矿物的行为

铝土矿碱液矿浆通电溶出提取氧化铝是一种新的工艺,本文研究了在交变电场作用下,铝土矿中ＳｉＯ２ 和ＴｉＯ２ 在溶出过程中的行为。     

电解液中甲酰胺浓度对阳极氧化制备TiO_2纳米管阵列形貌和光催化性能的影响

分别以0.5%HF水溶液(A)、0.3 mol/L NH4F+70%H2O+30%甲酰胺(体积分数)(B)、0.3 mol/L NH4F+30%H2O+70%甲酰胺(体积分数)(C)和0.3 mol/L NH4F+3%H2O+97%甲酰胺溶液电解液(体积分数)(D)作为电解液,对比研究甲酰胺含量对电化学阳极氧化TiO2纳米管阵列的形貌、结构和光催化性能的影响。结果表明:TiO2纳米管阵列长度随甲酰胺含量的增加而增加;水基电解液A中制备的纳米管长度、壁厚和管径分别约为600、20和100 nm,且分布不均匀;甲酰胺基电解液D中制备的纳米管长度、壁厚和管径分别约为10μm、5 nm和60 nm,且管径分布均匀;样品在O2中经450℃退火2 h后,发现甲酰胺基电解液A中制备的TiO2纳米管为单相锐钛矿结构,其它样品则为复合锐钛矿相和金红石相结构。光催化降解甲基橙的结果表明:随着TiO2纳米管阵列的厚度增加及管壁减小,紫外光光催化效率明显提高。     

Enhanced photocatalytic activity of new photocatalyst Ag/AgCl/ZnO

A new composite photocatalyst Ag/AgCl/ZnO was fabricated by a two-step synthesis method under the hydrothermal condition. The sample was characterized by XRD, TG-DSC, SEM, TEM, DRS and XPS. The results showed that the samples were composed of Ag, AgCl and ZnO, and the particle size was in the range of 100 nm-1 μm. Methyl orange (MO) was used as a representative dye pollutant to evaluate the photocatalytic activity of Ag/AgCl/ZnO. The photocatalytic activity of Ag/AgCl/ZnO catalyst was higher than that of the pure ZnO catalyst. It was found that the Ag/AgCl/ZnO structure changed to Ag/ZnO gradually after several repeated experiments. However, the photocatalytic ability of the sample was not reduced. Finally, a possible photocatalytic mechanism was proposed.     

Preparation of 3D ordered mesoporous anatase TiO_2 and their photocatalytic activity

Ordered crystalline mesoporous anatase titanium dioxides with different amounts of rutile were prepared by hard-template approaches using mesoporous silica(KIT-6)as the template. The resulting mesoporous materials were characterized by powder X-ray diffraction(PXRD), transmission electron microscope(TEM), N_2 adsorption and Raman spectroscopy. All mesoporous TiO_2 has three-dimensional(3 D) ordered mesostructures with large Brunauer–Emmett–Teller(BET) surface area and narrow pore size distribution(ca. 5 nm). It was found that the level of rutile phase in the mesoporous titanium oxide was related to the SO4_2-concentration in the starting materials. Their photocatalytic hydrogen production was evaluated and compared. It is found that low rutile content is beneficial for a high catalytic activity. All samples demonstrate a better activity than commercial P25.     

Fabrication of morphology-controlled TiO_2 photocatalyst nanoparticles and improvement of photocatalytic activities by modification of Fe compounds

Our previous studies suggested that redox reaction proceeded separately on specific exposed crystal faces of Ti O2 nanoparticles. Site-selective deposition of metal or metal oxide on Ti O2 specific exposed crystal faces successfully proceeded using the unique reactivity properties on the surface of Ti O2 nanoparticles under photoexcitation. A remarkable improvement of photocatalytic activity of shapecontrolled brookite and rutile Ti O2 nanorods with modification of Fe3compounds was observed under visible light.Crystal face-selective metal compound modification on exposed crystal faces of Ti O2 nanorods with brookite and rutile phases was successfully prepared. Brookite and rutile Ti O2 nanorods prepared by site-selective modification with metal compounds should be ideal visible-light responsive Ti O2 photocatalysts because of the remarkable suppression of back electron transfer from Ti O2 to oxidized metal compounds on the surface of the Ti O2 nanorod with a brookite or rutile phase. In this paper, the development of exposed crystal face-controlled Ti O2 nanorods with rutile and brookite phases was described. The obtained rutile and brookite Ti O2 nanorod, showing remarkably high activity for degradation of organic compounds compared with the photocatalytic activities of anatase fine particles(ST-01), is one of the most active commercially available photocatalysts for environmental cleanup in Japan. The technology of visiblelight responsive treatment for morphology-controlled rutile and brookite Ti O2 nanorods by crystal face-selective modification of Fe3compounds was also discussed in this paper. The Fe3compound-modified rutile and brookite Ti O2 nanorods show much higher activity than conventional visible-light responsive N-doped Ti O2, which is commercially available in Japan.     

包覆结构CeO_2/SiO_2复合磨料的合成及其应用

以正硅酸乙酯水解所得的SiO_2微球为内核,采用均匀沉淀法制备具有草莓状包覆结构的CeO_2/SiO_2复合粉体.利用X射线衍射仪、透射电子显微镜、X射线光电子能谱仪(XPS)、动态光散射仪和Zeta电位测定仪等手段,对所制备样品的物相结构、组成、形貌和粒径大小进行表征.将所制备的包覆结构CeO_2/SiO_2复合粉体用于硅晶片热氧化层的化学机械抛光,用原子力显微镜(AFM)观察抛光表面的微观形貌,测量表面粗糙度,并测量材料去除率.结果表明:所制备的CeO_2/SiO_2复合颗粒呈规则球形,平均粒径为150~200 nm,CeO_2纳米颗粒在SiO_2内核表面包覆均匀.CeO_2颗粒的包覆显著地改变复合颗粒表面的电动力学行为,CeO_2/SiO_2复合颗粒的等电点为6.2,且明显地偏向纯CeO_2;CeO_2外壳与SiO_2内核之间形成Si-O-Ce键,两者产生化学键结合;抛光后的硅热氧化层表面在2 μm×2 μm范围内粗糙度为0.281 nm,材料去除率达到454. 6 nm/min.     

Controllable synthesis and tunable photocatalytic activity of TiO_2 nanowires via alcohol-thermal method

Titania nanowires(TiO_2-NW) with tunable aspect ratios and morphologies were directly synthesized using a simple alcohol-thermal technique. Specifically,ethanol and acetic acid were used as solvents and lithium ion was used as the capping agent to promote the conversion of titanium butoxide into TiO_2-NW. The morphologies and crystal phases of TiO_2-NW were determined by the molar ratio of solvents and the content(mol%) of lithium ion. The band gap of TiO_2-NW with pure anatase phase is slightly bigger than that of TiO_2-NW with a mixture of anatase and rutile phases. All TiO_2-NW could achieve effective decolorization of methyl blue(the decolorization rate is over 95%) after 35-min ultraviolet(UV) irradiation.     

溶胶-凝胶ZrO_2/SiO_2双层减反膜(英文)

以锆酸丙酯[Zr(OPr)4]、正硅酸乙酯(TEOS)为原料,用溶胶-凝胶提拉法涂膜,制备了高透过的λ/4-λ/4型ZrO2/SiO2双层减反膜。以锆酸丙酯为前驱体,乙酰丙酮为络合剂,在盐酸的催化条件下,于乙醇溶剂中水解制备ZrO2溶胶。ZrO2溶胶具有很好的稳定性。制备的双层减反膜具有很好的减反效果,在石英玻璃基片二面涂膜,在激光三倍频波长351nm处透过率达到99.41%,在BK-7光学玻璃基片上涂制的双减反层膜在基频波长1053nm处透过率达到99.63%。该减反膜的均方根粗糙度(RMS)为1.038nm。膜层具有较高的激光损伤阈值,在激光波长为1064nm,脉冲宽度为1ns时,ZrO2膜的激光损伤阈值为19.6J/cm2,双层减反膜的激光损伤阈值为16.8J/cm2。     

Morphology and photocatalytic performance of nano-sized TiO_2 prepared by simple hydrothermal method with different pH values

pH value is a key factor in the preparation of nano-sized TiO_2 with hydrothermal method. Using Ti(SO_4)_2 as the titanium source, H_2O_2 as the complexing agent, NaOH and HCl as the pH value regulator, nanosized TiO_2 powder with various morphologies and sizes was synthesized. Changes in morphology, size and phase type with pH values of samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. Results show that under the present preparation conditions, TiO_2 powder is an anatase phase with pH value less than 11, but is more likely to be a brookite phase with pH value more than 11. With the increase in pH value from 1 to 11 in hydrothermal environment, nano-sized anatase TiO_2 gradually grows up in all directions.{001},{101}and{100}groups of crystal plane are the exposed crystal planes of nano-sized anatase TiO_2for the (004),(101) and (200) facets found in high-resolution TEM image. The photocatalytic performance of nano-sized TiO_2 with different morphologies was compared by measuring their photocatalytic degradation rates for methylene blue under ultraviolet light. Results show that anatase TiO_2 prepared under the alkalescenthydrothermal environment (pH=9, 11) has a better photocatalytic degrading performance. Different sizes and phases of nanoscaled TiO_2 powders with different photocatalytic performances can be prepared by the control of pH value of hydrothermal solutions.     

原位合成Ag／Y2O3和Ag／CeO2电接触材料研究

采用原位合成技术成功制备了Ag／Y2O3和Ag／CeO2电接触材料。X射线衍射分析表明反应合成材料中的相是Ag和Y2O3，C2O2：BSE图像显示：稀土氧化物在基体中呈球状弥散分布，粒径约为0．1μm～0．4μm，界面清洁，内氧化层与基体结合良好，改善了增强相与基体浸润不良的问题，并使材料致密度得到提高。测量材料的物理性能和力学性能，发现2种氧化物对基体的影响基本趋于一致。分析氧化物的原位形核机制，认为是氧在基体金属中通过克服原子间势垒扩散进入合金内部，发生择优氧化。扩散的主要方式是体扩散，生成的增强相牢固地嵌入基体，使得该复合材料的界面结合紧，综合性能优良。     

纳米TiO2同时增强增韧不饱和聚酯树脂（TiO2／UPR）的研究

用“反应法”制备纳米TiO2/UPR，在反应过程中纳米TiO2粉发生轻微水解反应，产生的羟基与不饱和聚酯中的羧基反应，成功地将纳米TiO2粒子接入不饱和聚酯长链，这种新的结构实现了对不饱和聚酯同时增强增韧改性，纳米TiO2/UPR弯曲强度和冲击强度较UPR分别提高了55％和46％，当纳米TiO2含量从1％增加至10％时，发现纳米TiO2/UPR有明显的脆－韧转变现象，纳米TiO2含量6％时为脆－韧转变点。