锌离子掺杂的二氧化钛介孔空心微球的制备及光催化性能

以二氧化硅为模板,钛酸四丁酯(TBOT)为钛源,硝酸锌为锌源,采用溶胶凝胶法制备了锌离子掺杂的介孔二氧化钛空心微球。采用X射线衍射(XRD)、比表面积(BET)、透射电镜(TEM)、扫描电镜(SEM)和X射线光电子能谱(XPS)等技术对样品进行表征,以亚甲基蓝(MB)的光催化降解为目标反应评价其光催化活性。结果表明,去核之后的复合微球为空心微球,壁厚为20 nm左右。钛酸四丁酯溶液的滴加时间对微球的形貌影响较大,当滴加时间大于15 min时,可以得到结构清晰的空心微球。用氢氧化钠溶液去除二氧化硅核,反应90 min,二氧化硅可以被完全去除。X射线衍射表明,实验得到的掺杂锌离子的空心微球和没有掺杂锌离子的空心微球都是锐钛矿。当锌离子的摩尔分数为0.3%时,二氧化钛空心微球的晶粒尺寸最小,比表面积最大,催化亚甲基蓝降解的效率最高。     

锌离子掺杂的二氧化钛介孔空心微球的制备及光催化性能

以二氧化硅为模板,钛酸四丁酯（TBOT）为钛源,硝酸锌为锌源,采用溶胶凝胶法制备了锌离子掺杂的介孔二氧化钛空心微球。采用X射线衍射（XRD）、比表面积（BET）、透射电镜（TEM）、扫描电镜（SEM）和X射线光电子能谱（XPS）等技术对样品进行表征,以亚甲基蓝（MB）的光催化降解为目标反应评价其光催化活性。结果表明,去核之后的复合微球为空心微球,壁厚为20nm左右。钛酸四丁酯溶液的滴加时间对微球的形貌影响较大,当滴加时间大于15min时,可以得到结构清晰的空心微球。用氢氧化钠溶液去除二氧化硅核,反应90min,二氧化硅可以被完全去除。X射线衍射表明,实验得到的掺杂锌离子的空心微球和没有掺杂锌离子的空心微球都是锐钛矿。当锌离子的摩尔分数为0.3%时,二氧化钛空心微球的晶粒尺寸最小,比表面积最大,催化亚甲基蓝降解的效率最高。     

原位碳、氮共掺杂二氧化钛空心球的制备与可见光光催化性能

在H₂O₂-HF 的乙醇-水混合溶液中, 通过水热处理碳氮化钛(TiCN)制备了碳、氮共掺杂TiO₂ 空心球(CNTH). 用X 射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X 射线光电子能谱(XPS)和紫外-可见(UV-Vis)吸收光谱表征了所制备的样品. 在可见光(λ≥400 nm)照射下, 通过降解甲基蓝检测了碳、氮共掺杂TiO₂空心球的光催化活性. 结果表明, 源于TiCN中的部分碳和氮原子原位掺入了TiO₂的晶格中, 部分碳掺入TiO₂点阵的间隙中. 该材料在整个可见光区展示了增强的可见光吸收, 其带边明显红移. 光催化研究表明在强可见光吸收和独特的空心球结构的协同作用下, 碳、氮共掺杂TiO₂空心球展示了比P25更高的可见光光催化活性.     

简易模板剂法制备多级介孔TiO2微球及其在染料敏化太阳能电池中的性能

采用模板剂法一步合成分级结构的介孔TiO₂微球, 考察了烷基胺类模板剂中烷基链长度对介孔TiO₂微球合成及性能影响. 将其应用于染料敏化太阳能电池的光阳极半导体薄膜中, 得到了9.5%-10.1%的高能量转换效率. X射线衍射(XRD)、物理吸附仪(BET)、扫描电镜(SEM)等的分析结果表明: 分级结构介孔TiO₂微球的晶相为纯锐钛矿型; 介孔TiO₂微球表面粗糙, 的纳米粒子堆积形成, 使微球具有介孔性质和较适宜的比表面积. 介孔TiO₂微球堆积形成了利于物质扩散的通道并具有良好的光散射效果; 同时微球介孔粗糙表面保证了染料的大量吸附, 从而提高了电池的光电流. 通过电化学阻抗分析结果验证了分等级结构介孔TiO₂微球光阳极有利于电解液的传输和物质扩散的优异性能.     

金红石相TiO2-石墨烯复合材料的制备及其光催化性能

以鳞片石墨为原料, 用改进的Hummers法制备氧化石墨烯(GO), 以异丙醇钛为钛源经一步水热法制备得到金红石相TiO₂-石墨烯复合材料(rGO-TiO₂), 考察了氧化石墨烯用量对复合材料光催化性能的影响. 采用X射线衍射(XRD), 比表面积(BET), 透射电镜(TEM), 扫描电镜(SEM), 拉曼光谱, 紫外-可见(UV-Vis)吸收光谱和荧光光谱(PL)等测试手段对复合材料进行表征. 结果表明: 复合材料中TiO₂为针簇状结构的金红石相, 与石墨烯能够均匀复合; 与纯金红石相TiO₂相比, 复合材料具有较大的比表面积. 研究了该复合材料在紫外光下对罗丹明B 以及可见光下对甲基橙光降解效果. 当氧化石墨烯浓度为0.5 mg·mL^-1时, 制备得到的复合材料rGO-TiO₂具有较好的光催化效果.     

金红石相TiO2纳米棒的氢化处理及其光催化活性

以钛酸四丁酯为钛源,通过盐酸调制的水热法制备出了具有棒状结构的金红石相纳米TiO₂,并进一步进行高温氢化处理. 采用X射线衍射（XRD）,透射电镜（TEM）,紫外-可见-近红外漫反射（UV-Vis-NIR DRS）,电子顺磁共振（EPR）和表面光伏（SPS）等测试手段对样品进行表征,以气相乙醛和液相苯酚为目标污染物考察催化剂的光催化活性. 结果表明：随着高温氢化处理时间的延长,TiO₂样品的可见光吸收逐渐增强,其颜色逐渐由白色转变成灰色,这主要与引入的Ti³⁺/氧空位缺陷有关. 表面光电压谱和羟基自由基测试表明,适当时间的氢化处理有利于光生电荷的分离. 在光催化氧化降解气相乙醛和液相苯酚过程中,经适当时间氢化处理的样品表现出高的可见光催化活性. 并且可见光催化活性的规律与紫外光下的是一致的. 这是因为氢化处理后在导带底下方引入了缺陷能级,拓展了可见光响应. 过度的氢化处理会在TiO₂导带下方引入较低的缺陷能级,使光生电荷的复合加剧,导致光催化活性降低.     

光驱动多孔无定形TiO2的形成机制与光催化性能的研究

以钛酸正丁醇和乙二醇为原料,采用溶剂热法合成了钛乙二醇盐(TG)前躯体,在高压汞灯照射下制备出无定形TiO2。利用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)、紫外-可见吸收光谱(UV-Vis)、表面光电压谱(SPS)、N2吸附-脱附对所得材料进行了结构和性能的表征。借助X射线吸收精细结构(XAFS)对无定形TiO2的形成机制进行了分析,并通过硝基苯的还原反应考察了材料的光催化性能。结果表明:在紫外光驱动无定形TiO2的形成过程中,中心元素Ti4+的配位环境发生变化,由八面体结构转变为四面体结构;由于特殊的孔道结构使得多孔无定形TiO2显示出较好的光催化活性。     

Preparation,Characterization and Photocatalytic Activity of Lanthanum Doped Mesoporous Titanium Dioxide

Lanthanum doped mesoporous titanium dioxide photocatalysts with different La content were synthesized by template method using tetrabutyltitanate (Ti(OC₄H₉)₄) as precursor and Pluronic P123 as template. The catalysts were characterized by thermogravimetric dif-ferential thermal analysis, N₂ adsorption-desorption measurements, X-ray diffraction, and UV-Vis adsorption spectroscopy. The effect of La³⁺ doping concentration from 0.1% to 1% on the photocatalytic activity of mesoporous TiO₂ was investigated. The characterizations indicated that the photocatalysts possessed a homogeneous pore diameter of about 10 nm with high surface area of 165 m²/g. X-ray photoelectron spectroscopy measurements in-dicated the presence of C in the doped samples in addition to La. Compared with pure mesoporous TiO₂, the La-doped samples extended the photoabsorption edge into the visible light region. The results of phenol photodecomposition showed that La-doped mesoporous TiO₂ exhibited higher photocatalytic activities than pure mesoporous TiO₂ under UV and visible light irradiation.     

Gd-N共掺杂SrTiO3/TiO2复合纳米纤维制备及光催化性能

以静电纺丝技术制备的TiO_2纳米纤维为基质和反应物,结合一步水热法制得Gd-N共掺杂SrTiO_3/TiO_2复合纳米纤维光催化剂。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电镜(HRTEM)、X射线光电子能谱(XPS)、紫外-可见漫反射(UV-Vis DRS)和荧光光谱(PL)等方法对其微观结构、形貌和光学性能进行表征。结果表明:SrTiO_3和TiO_2形成异质结能够使光生电子和空穴得到很好的分离,而Gd-N共掺杂产生新带隙,可以拓宽光谱响应范围至可见光区,并引起晶格缺陷,成为光生电子-空穴对的浅势捕获阱。Gd-N共掺杂与异质结的协同作用有效提高了SrTiO_3/TiO_2复合纳米纤维的可见光催化活性。     

Characterization of mesoporous nanocrystalline TiO2 photocatalysts synthesized via a sol-solvothermal process at a low temperature

Nanocrystalline TiO₂ samples with mesoporous structure were prepared via a solvothermal treatment of surfactant-stabilized TiO₂ sols. The samples were obtained from media of different acidities including nitric acid, deionized water, and ammonia (denoted as HT-1, HT-2 and HT-3, respectively). These samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂-sorption (BET surface area), micro-Raman spectroscopy, infrared absorption spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the samples were tested by the self-photosensitized degradation of an azo dye, Mordant Yellow 10 (MY), in aqueous solution under visible light irradiation. The results reveal that all three samples have high surface area and are pure anatase phase. The sample prepared in nitric acid medium possesses the most ideal mesoporous structure and also exhibits a blue shift in the Raman spectrum. All three samples show much higher photocatalytic activity than the commercial P-25. The activity order of the three samples is HT-1>HT-2>HT-3.     

Characterization and evaluation of the photocatalytic properties of wormhole-like mesoporous silica incorporating TiO2, prepared using different hydrothermal and calcination temperatures

TiO₂?CSiO₂ mesoporous materials were synthesised by deposition of TiO₂ nanoparticles prepared by the sol?Cgel method on to the internal pore surface of wormhole-like mesoporous silica. In this work we synthesised wormhole-like mesoporous silica of different surface area by changing the hydrothermal temperature (70, 100, or 130?°C). Subsequent to this, titania solution was deposited on to the inner surface of the pores and this was followed by calcination at different temperatures (400, 600, or 800?°C). The effect of different hydrothermal and calcination temperature on the photocatalytic properties was evaluated. The samples were characterized by N₂-sorption, X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. The effect of different hydrothermal and calcination temperatures on the photocatalytic properties was evaluated by measuring the degradation of methylene blue in aqueous solution under UV light irradiation (mercury lamp, 125?W). The results indicated that appropriate surface area and degree of crystallinity are two important factors for obtaining high photocatalytic efficiency. Samples prepared at a hydrothermal temperature of 100?°C and calcined at 800?°C had the best photocatalytic performance, because of the highest surface area and high crystallinity.     

Preparation and characterization of SiO2/TiO2 composite microspheres with microporous SiO2 core/mesoporous TiO2 shell

SiO₂/TiO₂ composite microspheres with microporous SiO₂ core/mesoporous TiO₂ shell structures were prepared by hydrolysis of titanium tetrabutylorthotitanate (TTBT) in the presence of microporous silica microspheres using hydroxypropyl cellulose (HPC) as a surface esterification agent and porous template, and then dried and calcined at different temperatures. The as-prepared products were characterized with differential thermal analysis and thermogravimetric (DTA/TG), scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption. The results showed that composite particles were about 1.8 μm in diameter, and had a spherical morphology and a narrow size distribution. Uniform mesoporous titania coatings on the surfaces of microporous silica microspheres could be obtained by adjusting the HPC concentration to an optimal concentration of about 3.2 mmol L⁻¹. The anatase and rutile phase in the SiO₂/TiO₂ composite microspheres began to form at 700 and 900 °C, respectively. At 700 °C, the specific surface area and pore volume of the SiO₂/TiO₂ composite microspheres were 552 and 0.652 mL g⁻¹, respectively. However, at 900 °C, the specific surface area and pore volume significantly decreased due to the phase transformation from anatase to rutile.     

Preparation of a highly active nanocrystalline TiO2 photocatalyst from titanium oxo cluster precursor

Nanocrystalline TiO₂ (sample S1) was prepared from a titanium oxo cluster (Ti₇O₄(OEt)₂₀) precursor via a sol-gel route. This photocatalyst showed a higher photocatalytic activity than the TiO₂ (sample S2) obtained from titanium tetraisopropoxide. The samples were characterized by thermal analysis (TGA/DSC), X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy, N₂ adsorption (BET surface area), infrared absorption spectroscopy (FT-IR) and X-ray photoelectron spectroscopy. The characterization results show that both samples are anatase nanocrystals with particle sizes of about 12 nm, but the more photocatalytically active sample S1 has more surface hydroxyl groups and larger surface area and pore volume than sample S2.     

CdS/TiO2纳米管复合结构的制备与光电性能研究

利用阳极氧化法在钛金属基底表面制备一层TiO2纳米管阵列薄膜,然后通过水热反应在TiO2纳米管上负载CdS纳米粒子,形成CdS/TiO2纳米管的复合结构。利用SEM、XRD、XPS、UV-Vis等手段对其形貌和结构进行表征。进一步考察了CdS/TiO2纳米管的光电性能和光催化活性,结果表明,相比于TiO2纳米管,CdS/TiO2纳米管复合结构在紫外光和可见光下都具有更好的光催化活性及光电性能。     

Improved solar-driven photocatalytic performance of BiOI decorated TiO2 benefiting from the separation properties of photo-induced charge carriers

In this work, BiOI decorated TiO₂ photocatalysts were prepared in-situ by a facile hydrothermal method and characterized by X-ray diffraction (XRD), UV/Vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and surface photovoltage (SPV) spectroscopy. The reactive radicals during the photocatalytic reaction were detected by scavenger experiments. BiOI/TiO₂ composites exhibit higher performance than the pure TiO₂ towards photocatalytic decolorization of methyl orange (MO) aqueous solution, when the molar ratio of Bi/Ti is 2%, the sample has the highest photocatalytic activity. The enhanced photocatalytic performance of BiOI/TiO₂ could be ascribed to the separation properties of photo-induced charge carriers and strong interaction between BiOI and TiO₂. Based on the observations, a Z-scheme charge separation mechanism was proposed.     

Boron and nitrogen-codoped TiO2 nanorods: Synthesis, characterization, and photoelectrochemical properties

Boron and nitrogen codoped TiO₂ nanorods (BNTRs) were synthesized via two-step hydrothermal reactions using TiN as a starting material. The as-prepared samples were characterized by X-ray diffraction, field-emission scanning electron microscope (SEM), transmission electron microscopy and X-ray photoelectron spectroscopy techniques. The results showed that TiO₂ nanorods with the diameter of approximately 50–100 nm and the length of several micrometers were doped by the interstitial N and B. The nanorods were firstly formed in the hydrothermal synthesis of nitrogen doped TiO₂. The growing process of nanorods was observed by SEM and a most probable formation mechanism of the trititanate nanorods was proposed. The BNTRs showed a higher photocatalytic activity and a bigger photocurrent response than N–TiO₂ nanorods under visible light irradiation.     

Development of mesoporous TiO2 microspheres with high specific surface area for selective enrichment of phosphopeptides by mass spectrometric analysis

In this study, mesoporous TiO₂ microspheres were synthesized by simple hydrothermal reaction, and successfully developed for phosphopeptides enrichment from both standard protein digestion and real biological sample such as rat brain tissue extract. The mesoporous TiO₂ microspheres (the diameter size of about 1.0 μm) obtained by simple hydrothermal method were found to have a specific surface area of 84.98 m²/g, which is much larger than smooth TiO₂ microspheres with same size. The surface area of mesoporous TiO₂ microspheres is almost two times of commercial TiO₂ nanoparticle (a diameter of 90 nm). Using standard proteins digestion and real biological samples, the superior selectivity and capacity of mesoporous TiO₂ microspheres for the enrichment of phosphorylated peptides than that of commercial TiO₂ nanoparticles and TiO₂ microspheres was also observed. It has been demonstrated that mesoporous TiO₂ microspheres have powerful potential for selective enrichment of phosphorylated peptides. Moreover, the preparation of the mesoporous TiO₂ microspheres obtained by the hydrothermal reaction is easy, simple and low-cost. These mesoporous TiO₂ microspheres with the ability of large scale synthesis can widely be applied for phosphorylated proteomic research.     

Bi2WO6/TiO2纳米管异质结构复合材料的多模式下的光催化活性比较

以TiO₂纳米管为模板,采用多组分自组装结合水热法制备Bi₂WO₆/TiO₂纳米管异质结构复合材料。通过多种技术如X射线衍射（XRD）,X射线光电子能谱（XPS）,N₂吸附-脱附,扫描电镜（SEM）,高分辨透射电镜（HRTEM）和紫外可见漫反射吸收光谱（UV-Vis DRS）考察所制备样品的组成、结构、形貌、光吸收和电子性质。Bi₂WO₆纳米片或纳米粒子分布在TiO₂纳米管上,形成异质结构。随后,通过在紫外、可见和微波辅助光催化模式下降解染料罗丹明B（RhB）来评价复合催化剂的光催化活性。与TiO₂纳米管和Bi₂WO₆相比,Bi₂WO₆/TiO₂-35纳米管在多模式下表现出更优异的光催化活性。与紫外和可见降解模式相比,Bi₂WO₆/TiO₂-35纳米管在微波辅助光催化模式下对RhB的降解效率最高。这种增强的光催化活性源于适量Bi₂WO₆的引入、纳米管独特的形貌特征和降解模式所引起的增强的量子效率。降解过程中的活性物种被证明是h⁺,·OH和·O₂^-自由基。而且,在微波辅助光催化模式下,可产生更多的·OH和·O₂^-自由基。     

Preparation of mesoporous TiO2/CNT nanocomposites by synthesis of mesoporous titania via EISA and their photocatalytic degradation under visible light irradiation

Stabilized mesoporous TiO₂ was synthesized by evaporation induced self assembly (EISA) method and mechanically incorporated into single-walled carbon nanotubes (SWCNT) with different ratios. The physicochemical properties of the nanocomposites (mesoporous TiO₂/SWCNT) materials were investigated by Brunauer–Emmett–Teller (BET) measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), photoluminescence (PL) and ultraviolet–visible (UV–Vis) spectroscopy measurements. The catalytic activity of mesoporous TiO₂ and nanocomposites were assessed by examining the degradation of rhodamine B as model aqueous solution under visible light. CNTs are facilitating the photocatalytic activity of mesoporous TiO₂ in the degradation of rhodamine B efficiently.     

Rapid Synthesis of Mesoporous TiO2 for the Photoanodes in Dye Sensitized Solar Cells

Mesoporous TiO₂ microspheres with high specific surface areas were synthesized by means of a facile one‐step microwave hydrothermal process without using any template. The mesoporous materials were rapidly achieved using TiCl₄, urea and ammonium sulphate at comparatively low microwave power (400 W) for 8 min irradiation. The morphology and microstructure of the as‐prepared products were characterized by field emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer‐Emmett‐Teller (BET) surface area analysis. Structural characterization indicates that the TiO₂ microspheres display mesoporous structure. The average pore sizes and BET surface areas of the spheres were 5.3 nm and 222 m²g^?1, respectively. The mesoporous nanocrystals synthesized at 160 °C for 8 min were then used to prepare the photoanode for dye sensitized solar cells (DSSCs). A high power conversion efficiency of 5.72% was achieved from the mesoporous TiO₂ based photoanode, representing about 25.7% improvement over the efficiency of P25 photoanode.