介孔TiO2的合成及其对刚果红的吸附性能

分别以硫酸钛和钛酸丁酯为原料,采用水热法制备介孔TiO2,对制得的样品进行X射线衍射、N2吸附-脱附、表面羟基面密度测定等表征,并以刚果红为目标污染物研究样品的吸附性能。结果表明:所得样品均为介孔材料;由硫酸钛和钛酸丁酯制备TiO2的比表面积分别为153.2、314.3 m2/g,对刚果红的吸附率分别达到90%和70%以上,吸附速率符合拟二级动力学方程。     

TiO2负载硅铝陶瓷介孔球对甲基橙吸附和光催化 降解的研究

：以自制硅铝陶瓷介孔球为基体,经溶胶凝胶法制备TiO2溶胶并将其负载于硅铝陶瓷介孔球表面,用于甲基橙溶液的吸附和光催化降解,再利用扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪和可见分光光度计对样品的表观形貌、晶体结构、吸附和光催化性能等进行表征和测定。研究结果表明：TiO2是以粗糙度较高的多层膜包覆于硅铝陶瓷介孔球表面且TiO2为锐钛矿晶型;在黑暗条件下,硅铝陶瓷介孔球和TiO2负载硅铝陶瓷介孔球对甲基橙仅起到吸附作用,且两者的吸附性能较接近;但在紫外光照条件下,TiO2负载硅铝陶瓷介孔球对甲基橙除有吸附作用外还表现出较好的光催化降解活性。     

介孔γ-Fe2O3的制备及其对氟离子吸附性能的研究

以十六烷基三甲基溴化铵（CTAB）为模板剂,用热分解法制备了介孔γ-Fe2O3,对制得的样品进行了XRD、磁性、N2吸附-脱附表征,结果表明,所得样品的结晶度与磁性随着模板剂用量的增加而减小,最大比表面积为149．8m2／g;介孔γ-Fe2O3对氟离子的吸附平衡时间为30min,二级动力学模型能够很好地拟合吸附动力学数据;溶液的pH为3时,介孔γ-Fe2O3对氟离子的吸附率最高,通过Langmuir方程计算得极限吸附量为9．7mg／g。     

镧、铈改性介孔氧化铝对氟离子的吸附

以La、Ce为改性物负载至其他载体表面作为高效除氟吸附剂已经受到广泛的关注。但是将La和Ce负载到介孔氧化铝(MA)却少见报道。本研究制备了La和Ce改性介孔氧化铝并将其用于氟的去除。采用N2吸脱附等温线、X射线衍射(XRD)、傅里叶红外光谱(FTIR)对该吸附剂的结构性质进行了表征。同时,考察了吸附剂接触时间、初始浓度和溶液pH等吸附条件对氟离子吸附效果的影响。结果表明,反应在150 min时达到吸附平衡,此时La/MA的氟去除率达92. 2%,吸附氟容量大小为La/MA Ce/MA MA;氟吸附量随初始浓度的增大而增大;在pH值为5～9时,除氟效果较好;吸附等温线方程均符合Langmuir等温吸附模型; La/MA的氟离子最大吸附容量为27. 9 mg/g;共存阴离子对氟吸附的影响程度为CO32- SO42- NO3- Cl-。最后比较了吸附前后的FTIR,可以看出La/MA对氟离子去除效果最佳。     

介孔TiO_2膜的制备及其吸附性能研究

以钛酸四异丙脂为原料,采用粒子型溶胶路线制备出稳定的TiO2溶胶,通过浸渍涂膜法,在孔径为100nm的管式Al2O3微滤膜支撑体上制备出介孔TiO2膜。研究了介孔TiO2膜的制备过程对其完整性及孔结构的影响,同时考察了非负载介孔TiO2膜对染料酸性橙7和亚甲基蓝的吸附性能。在溶胶中加入适量的PVA和HPC,控制浸涂时间,在450℃焙烧1h可获得完整的介孔TiO2膜,膜厚约0.5μm,孔径分布于3~10nm。介孔TiO2膜对酸性橙7及亚甲基蓝吸附量随pH值变化,调节pH值可减少吸附造成的膜污染。     

APTES改性介孔硅的制备及对重金属离子的吸附性能研究

以介孔二氧化硅为原材料,将3-氨基丙基三乙氧基硅烷(APTES)改性接枝到介孔硅表面,对改性介孔二氧化硅进行表征分析。介孔硅具有较高的比表面积,而APTES中的氨基具吸附重金属功能,使得氨基改性介孔硅吸附重金属离子的功能更强。探讨了介孔硅对重金属的吸附性能,考察氨基功能化介孔硅吸附剂对重金属镉离子(Cd~(2+))、铅离子(Pb~(2+))、铜离子(Cu~(2+))的选择吸附作用。实验结果表明,吸附时间8h以上,介孔硅和改性介孔硅对Cd~(2+)的吸附量分别为0.14、0.15mg/g,对Pb~(2+)的吸附量分别为0.14、0.15mg/g,对Cu~(2+)的吸附量分别为0.13、0.15mg/g;在温度为25℃,震荡时间为24h的条件下,改性介孔硅对Pb~(2+)吸附性能最好,吸附量为0.13mg/g,其次是Cu~(2+)为0.02mg/g,最后是Cd~(2+)为0.01mg/g,说明在3种金属的混合溶液中,改性介孔硅对Pb~(2+)有良好选择吸附性。     

Bi掺杂纳米TiO2光催化甘油水溶液制氢性能研究

采用溶胶–凝胶法制备了TiO2和Bi掺杂的TiO2纳米颗粒,用N2吸附-脱附、SEM、XRD、FT-Raman、UV-VisDRS对光催化材料的孔结构、表面构造、能带结构、吸光特性进行了表征,并考查了其光催化甘油水溶液制氢反应的活性.结果表明:Bi掺杂后的TiO2为介孔结构的锐钛矿晶型纳米颗粒,其分散度明显增加,晶粒变小,比表面积增大;Bi掺杂使得TiO2禁带内形成杂质能级,降低了禁带能量,增加了光生电子和空穴的分离效率,有利于将TiO2的吸光带边界扩展至可见光区;Bi掺杂的TiO2样品表现出了远高于纯TiO2的光催化甘油水溶液制氢性能,2mol%Bi掺杂的样品在紫外光和模拟太阳光辐射下表现出了最高产氢活性,其速率分别为3534.8μmol/(h.gcat)和455.7μmol/(h.gcat).     

席夫碱桥联介孔SiO_2的合成及其对Cu~(2+)吸附性能的研究

采用水热法,以十二胺为模板剂,苯基桥链硅氧烷为有机硅源的共缩聚法合成桥链双亚胺席夫碱功能介孔二氧化硅(PMOs),并利用FT-IR,XRD,N_2吸附/脱附及TEM对合成的样品进行表征,考察了桥联有机硅源量对PMOs材料结晶和介孔结构特性的影响。结果显示,通过苯基桥链硅氧烷为有机硅源可实现介孔二氧化硅的席夫碱功能化,样品的孔径为2.65~2.96nm的介孔结构范围。但随着桥联有机硅源量的增加,受有机结构的影响,PMOs材料的晶型有序度和介孔规整度下降。吸附性能显示,PMOs材料对Cu~(2+)具有较好的吸附性能,对铜离子(Cu~(2+))的最高吸附率达到90.35%。     

离子液中介孔TiO2的制备及其形成机理研究

首次以不同咪唑基离子液为结构导向剂，通过水热合成制备出介孔TiO2分子筛。考察了合成条件对产物结构的影响，结果表明，离子液用量、离子液类型、晶化温度、晶化时间等因素对TiO2介孔分子筛的形成和孔道结构均有影响，其中晶化温度及离子液类型的影响最为明显，在较低晶化温度时（100℃）产物孔径分布范围宽，但仍为介孔结构，当温度升高到180℃时，孔径变大并开始失去介孔特征，机理为晶化温度会影响离子液与无机物的相互作用速度，高温时TiO2结晶度也会迅速提高导致失去介孔结构，最佳晶化温度为120℃；咪唑基离子液其碳链长度不同，使用短链离子液时产物无介孔结构，当使用长链离子液时产物孔道结构良好，作为结构导向剂其碳链长度会决定产物孔道生长趋势和长度，最佳离子液类型为[C16MIM]Br．X射线衍射谱（XRD）表明产物为锐钛矿型介孔TiO2；透射电镜（TEM）观察表明产物具有规整的孔道结构（3～4nm），与低温氮吸附法分析结果一致；激光粒度分析表明产物粒度较小（20～40nm）并且分布范围窄。     

磁性炭基TiO_2复合光催化剂的制备及降解罗丹明B的研究

采用浸渍法将介孔炭(MC)和铁酸镍复合制备出磁性介孔炭复合载体(MMC);采用溶胶-凝胶法在磁性复合载体上负载活性组分TiO2制成新型磁性复合光催化剂(TiO2/MMC)。样品采用X射线衍射(XRD)、透射电镜(TEM)、氮气吸附-脱附等和振动磁强计(VSM)表征。结果表明:TiO2/MMC复合光催化剂包含NiFe2O4磁性组分和锐钛矿TiO2活性组分,晶粒粒度约为0.15~0.2μm,BET比表面积约126m2/g,饱和磁化强度5.611emu/g。对罗丹明B染料废水光催化降解性能测试表明:TiO2/MMC复合光催化剂具有较高暗吸附特征和光催化活性,30min内暗吸附率可达33.168%,在8w低压汞灯照射下,3.5h降解率达到100%。因此,TiO2/MMC兼具良好的磁回收性能和光催化活性。     

二次纳米自组装法制备Ni-Mo/TiO2-Al2O3催化剂

依据框架式大孔容介孔固体材料的形成机理,采用二次纳米自组装法制备出高比表面积和大孔容的纳米TiO2-Al2O3载体.应用低温氮吸附、扫描电子显微镜(SEM)和透射电子显微镜(TEM)技术研究了TiO2助剂对TiO2-Al2O3载体的介孔结构和纳米粒子团聚效应的影响,以及浸渍方法对Ni-Mo/TiO2-Al2O3催化剂的孔结构和金属组分分散性的影响.结果表明,适量TiO2对纳米TiO2-Al2O3载体有较好的扩孔和抗聚集效应;二次纳米自组装TiO2-Al2O3(TiO2,20%)粉体具有较大的比表面积和比孔容以及低纳米尺度.分步浸渍法制备的催化剂上Ni-Mo活性组分具有良好的分散性,其分布较宽的介孔系统适合渣油的加氢精制过程.     

Reactive dyes remotion by porous TiO2-chitosan materials

In this work, the aim was to evaluate the remotion (adsorption plus degradation) of two reactive dyes, Methylene Blue (MB) and Benzopurpurin (BP), from aqueous solutions by the utilization of TiO2-chitosan microporous materials. Two different TiO2-chitosan hybrid materials were synthesized: TiO2-Chit A with 280 mg chitosan/gTiO2 and TiO2-Chit B with 46.76 mg chitosan/g TiO2. Adsorption data obtained at different solution temperatures (25, 35, and 45 degrees C) revealed an irreversible adsorption that decrease with the increment of T. Langmuir, Freundlich and Sips isotherm equation were applied to the experimental data. The obtained parameters and correlation coefficient showed that the adsorption of both dyes on TiO2-Chit A at the three work temperatures was best predicted by the Langmuir isotherm, while Sips equation adjusted better to adsorption data on TiO2-Chit B. The adsorption enthalpy was relatively high and varied with T, indicating that interaction between adsorbent and adsorbate molecules was not only physical but chemical. There is a change in the adsorption heat capacity, (Delta(ads)C(p)<0), related with intense hydrophobic interactions. The kinetic adsorption data were processed by the application of Lagergren and Avrami models. It was found that adsorption of both dyes on both adsorbents under the operating conditions was best predicted by Avrami model. The variation of kinetic order, n, and k(av) with T are related to a pore followed by intra particle diffusion control of the adsorption rate. MB photodegradation on both TiO2-chitosan hybrid materials was of 91 (in A) and 41% (in B) and augmented with the chitosan content. For BP can be seen that the process in darkness resulted in a high remotion capacity than in UV light presence.     

溶剂对介孔二氧化钛结构及光催化活性的影响

在室温下采用不同溶剂直接合成出介孔TiO2，分别用场发射透射电镜（HRTEM）、透射电镜（TEM），X射线粉末衍射（XRD）和BET比表面测定等技术对TiO2进行了表征。结果表明：在该实验条件下能获得高比表面的介孔TiO2，溶剂的极性对孔结构有一定的影响，同时对甲基橙的光催化降解活性有较大的影响。     

Synthesis of nano titania particles embedded in mesoporous SBA-15: characterization and photocatalytic activity

Supported nanocrystalline titanium dioxide (TiO2) has been prepared by a post-synthesis step via Ti-alkoxide hydrolysis through the use of mesoporous SBA-15 silica. TiO2/SBA-15 composites with various TiO2 loading have been prepared and characterized by X-ray diffraction, nitrogen adsorption, Fourier transform infrared spectroscopy and diffusive reflective UV-vis spectroscopy. The addition of mesoporous SBA-15 prevents the anatase to rutile phase transformation and the growth of crystal grain. TiO2 did not block the SBA-15 pores, and their surface was fully accessible for nitrogen adsorption. Calcination in air of the composites up to 800 degrees C did not change the nanocrystal phase and slightly increased the domain size from 5.0 to 7.5 nm, indicating that the anatase TiO2 grains in the mesostructures have a relatively high thermal stability and proper pore diameter allows controlling the size of obtained titania particles. The TiO2/SBA-15 composites prepared by this study showed much higher photodegradation ability for methylene blue (MB) than commercial pure TiO2 nanoparticles P-25. Experimental results indicate that the photocatalytic activity of titania/silica mixed materials depends on the adsorption ability of composite and the photocatalytic activity of the titania, and there is an optimal ratio of Ti:Si, too high or low Ti:Si ratio will lower the photodegradation ability of the composites.     

Assembly of CdS quantum dots onto mesoscopic TiO(2) films for quantum dot-sensitized solar cell applications

Colloidal cadmium sulfide (CdS) quantum dots (QDs) were prepared and surface modified by mercaptosuccinic acid (MSA) to render a surface with carboxylic acid groups (MSA-CdS). The MSA-CdS QDs were then assembled onto bare TiO(2) mesoporous films using the carboxylic groups/TiO(2) interaction. The TiO(2) film was also surface modified by 3-mercaptopropyl trimethoxysilane (MPTMS) or 3-aminopropyl-methyl diethoxysilane (APMDS) to prepare, respectively, a thiol (-SH) or amino (-NH(2)) terminated surface for binding with the CdS QDs. The experimental results showed that the MPTMS-modified film has the highest adsorption rate and adsorption amount to the CdS QDs, attributable to the strong thiol/CdS interaction. In contrast, the adsorption rate and incorporated amount of the QDs on the bare TiO(2) film are much lower than for the silane-modified films. The incident photon-to-current conversion efficiency (IPCE) obtained for the CdS-sensitized TiO(2) electrode was about 20% (at 400?nm) for the bare TiO(2), 13% for the MPTMS-TiO(2), and 6% for APMDS-TiO(2). The current-voltage measurement under dark conditions reveals a higher dark current on the MPTMS-?and APMDS-modified electrodes, indicating a lower coverage ratio of CdS on these TiO(2) films. This result is attributed to the fast adsorption rate of CdS QDs on the bottleneck of a mesopore which inhibits the transport of the QDs deep into the inner region of a pore. For the bare TiO(2) film, the lower incorporated amount of CdS but higher energy conversion efficiency indicates the formation of a better-covered CdS QDs monolayer. The moderate adsorption rate of MSA-CdS QDs using the carboxylic acid/TiO(2) interaction is responsible for the efficient assembly of QDs onto the mesoporous TiO(2) films.     

金红石型TiO2纳米棒的制备及其在染料敏化太阳电池中的应用

采用十二烷基苯磺酸钠表面活性剂(DBS)辅助水热法合成TiO2纳米材料,XRD和TEM测试表明,不含DBS的TiO2溶胶水热处理后得到10~20nm锐钛矿型TiO2纳米颗粒;添加DBS后,生成了金红石型TiO2纳米棒.虽然金红石型TiO2纳米棒光电极的染料吸附性能和光电性能均不如锐钛矿型TiO2纳米颗粒光电极,但金红石型TiO2纳米棒漫反射性能较高.可用其制备具有光电转换性能的反射层,这种新型反射层使染料敏化太阳能电池光电转换效率提高了26.14%,而含Ti-nanoxide 300大颗粒TiO2构成的反射层仅能使电池光电转换效率提高11.04%.这种差异的根源在于金红石型TiO2纳米棒不仅具有散射光能力,其本身还可吸附染料进行光电转换.随着反射层厚度的增加,电池短路电流逐步提高.而不吸附染料且无光电转换能力的Ti-nanoxide 300传统反射层则没有这种功能.     

炭表面改性对负载型TiO_2/活性炭复合光催化剂性能的影响

采用HNO3、H2O2和O3对商品活性炭进行表面改性处理,考察了改性处理对活性炭表面基团、负载TiO2以及所形成的TiO2/活性炭复合光催化剂性能的影响。利用傅里叶红外光谱(IR)、X射线光电子能谱(XPS)、扫描电镜(SEM)及氮气吸附等手段对材料进行了表征。结果表明,3种改性方法均可有效提高活性炭载体表面的含氧官能团数量,但是对活性炭的比表面积和孔容影响不大;H2O2和O3对活性炭载体改性后可以提高对钛前驱体的吸附性能,HNO3改性有利于TiO2颗粒在活性炭表面的分散。使用改性后的活性炭作为载体制备的TiO2/活性炭光催化降解甲基橙的性能均高于未改性的TiO2/活性炭催化剂,其中以HNO3改性后的TiO2/活性炭活性最高。     

Adsorption and degradation of model volatile organic compounds by a combined titania-montmorillonite-silica photocatalyst

A series of adsorptive photocatalysts, combined titania-montmorillonite-silica were synthesized. The resultant photocatalysts consisted of more and more spherically agglomerated TiO(2) particles with increasing of TiO(2) content, and anatase was the only crystalline phase with nano-scale TiO(2) particles. With increasing of the cation exchange capacity to TiO(2) molar ratio, specific surface area and pore volume increased very slightly. In a fluidized bed photocatalytic reactor by choosing toluene, ethyl acetate and ethanethiol as model pollutants, all catalysts had relatively high adsorption capacities and preferred to adsorb higher polarity pollutants. Langmuir isotherm model better described equilibrium data compared to Freundlich model. Competitive adsorptions were observed for the mixed pollutants on the catalysts, leading to decrease adsorption capacity for each pollutant. The combined titania-montmorillonite-silica photocatalyst exhibited excellent photocatalytic removal ability to model pollutants of various components. Almost 100% of degradation efficiency was achieved within 120 min for each pollutant with about 500 ppb initial concentration, though the efficiencies of multi-component compounds slightly decreased. All photocatalytic reactions followed the Langmuir-Hinshelwood model. Degradation rate constants of multi-component systems were lower than those for single systems, following the order of toluene相似文献   

Synthesis and characterization of visible light driven mesoporous nano-photocatalyst MoO3/TiO2

A novel mesoporous-structured photocatalyst MoO3/TiO2 was synthesized through a modified sol-gel method by using P123 as the template, and the resulting nano-photocatalysts were characterized by X-ray diffraction (XRD), N2 adsorption measurements, transmission electron microscope (TEM), UV-vis spectroscopy, XPS and Raman techniques. Low-angle XRD and TEM images show the lack of long-range order in the as-prepared MoO3/TiO2, but the Mo species are homogenously dispersed on the anatase matrix. According to the results of N2 ads-desorption, the calcined products possess the high surface area and the pore size distribution centered between 4-7 nm. The calcined meso-MoO3/TiO2 materials exhibit the high photocatalytic activity for the degradation of MB (methylene blue) under visible light radiation.     

Mesoporous inverse opal TiO2 film as light scattering layer for dye-sensitized solar cell

The light harvesting efficiency of dye-sensitized solar cells was enhanced by using a scattering layer. Such as sphere type TiO2, inverse photonic crystal TiO2, hollow spherical TiO2. Among these materials, the TiO2 with inverse photonic crystal (IPC) structure, synthesized by self-assembly using spherical templates, has attracted much attention due to their photonic crystal characteristics and light scattering effects. However, when applied in the DSSCs, the surface area of IPC is very low that caused insufficient adsorption amount of dye molecules. In the present work, a scattering layer with mesoporous inverse photonic crystal (MIPC) TiO2 film was fabricated by the sol-gel reactions with surfactant-assisted sol-gel method using poly(methyl methacrylate) as the template and titanium (IV) isopropoxide as the TiO2 precursor. After removing the PMMA and surfactant, a highly ordered macroporous structure with mesopores were successfully obtained. The surface area and total pore volume of the MIPC were 82 m2/g and 0.31 cm3/g, respectively, which is much larger than those of the IPC. The DSSCs with the scattering layer of MIPC film exhibited 18 and 10% higher photo-conversion efficiency than those of cells only with a nano-crystalline TiO2 film and with scattering layer of IPC film. From UV-visible spectra of dye solutions, the MIPC film showed a higher amount of absorbed dye molecules than those of the reference and IPC films. Accordingly, an increase in the photo-current density through abundant adsorption of the dye, coupled with inherent light scattering ability can improve overall photo-conversion efficiency.