Ag/TiO2纳米粒子的制备及其光催化降解苯酚的性能研究

采用溶胶-凝胶法制备了TiO₂和Ag/TiO₂纳米粒子,采用涂覆法制备了TiO₂和Ag/TiO₂纳米粒子光催化剂基板样品。使用XRD、SEM和拉曼光谱等手段,对TiO₂和Ag/TiO₂纳米粒子进行了晶格结构和表面形貌研究;通过UV-Vis,研究了TiO₂和Ag/TiO₂纳米粒子光催化剂基板样品在光催化反应器中对苯酚的光催化降解性能。结果表明,制备的TiO₂和Ag/TiO₂纳米粒子均为纯净的金红石相,二者表面形貌并没有明显区别,Ag单质粒子成功负载在TiO₂纳米材料上;Ag单质粒子的负载,明显增强了TiO₂纳米粒子对可见光的吸收,且Ag/TiO₂纳米粒子薄膜对苯酚的光催化降解性能明显优于TiO₂纳米粒子薄膜;在光催化降解1 h后,TiO₂纳米粒子薄膜仅催化降解了溶液中30%(质量分数)的苯酚,且光催化降解出现了饱和趋势,而Ag/TiO₂纳米粒子薄膜可催化降解溶液中50%(质量分数)的苯酚,且在光催化降解3 h后,仍未出现饱和趋势。     

Ce-La-Ag共掺杂TiO2/玄武岩纤维复合光催化剂的制备和性能

以玄武岩纤维(BF)为载体,用溶胶凝胶法将Ce-La-Ag共掺TiO₂负载于BF上制备出Ce-La-Ag共掺杂TiO₂/玄武岩纤维复合光催化剂。用光催化降解氨氮废水,研究了烧结温度和废水的pH值对Ce-La-Ag-TiO₂/BF光催化活性的影响。结果表明：Ce-La离子与纳米Ag颗粒的协同作用使TiO₂的禁带宽度由3.2 eV降至2.15 eV。Ce-La-Ag-TiO₂的光催化活性优于纯TiO₂、Ag-TiO₂和Ce-La-TiO₂,负载到BF使其光催化活性进一步提高。当复合光催化剂的烧结温度为600 ℃、氨氮废水的pH值为10.5、模拟可见光的照射时间为360 min时,Ce-La-Ag-TiO₂/BF对氨氮废水重复降解5次的降解率仍高于88.2%。     

静电纺丝法制备PVA-SA-CuTsPc纳米纤维改性CMC-PVA/CS-PVA双极膜

分别用Fe3+离子和戊二醛作为交联剂对羧甲基纤维素钠(CMC)-聚乙烯醇(PVA)阳膜层和壳聚糖(CS)-聚乙烯醇阴膜层进行改性,利用静电纺丝法制备聚乙烯醇(PVA)-海藻酸钠(SA)-四磺酸基铜酞菁(CuTsPc)纳米纤维纺丝,引入中间界面层,制备CMC-PVA/PVA-SA-CuTsPc/CS-PVA双极膜(BPM),并用扫描电镜、接触角测定仪,电流密度-槽电压关系曲线、交流阻抗谱等对制备的双极膜进行了表征。研究结果表明,经PVA-SA-CuTsPc纳米纤维纺丝改性后,CMC-PVA阳膜表面亲水性增强,双极膜的中间界面层水解离效率提高,膜阻抗和槽电压下降。当电流密度为90 mA/cm2时,CMC-PVA/PVA-SA-CuTsPc/CS-PVA(w(CuTsPc)=3.0%)双极膜的电阻压降(即膜IR降)仅为0.5 V。     

稀土La掺杂TiO2纳米纤维高响应光催化降解染料研究

为了提高TiO₂光催化性能,并研究金属离子掺杂对TiO₂光催化性能的影响,采用静电纺丝技术和煅烧工艺制备稀土元素La掺杂TiO₂无机纳米纤维膜,通过SEM、XRD、FT-IR、TG测试对材料的形貌、结构进行表征,以亚甲基蓝为靶向降解剂,进一步深入研究La³⁺改性TiO₂光催化氧化降解染料的机理。结果表明,当染料浓度为10 mg/L,La³⁺掺杂改性纳米TiO₂纤维的浓度为15 mg/10 mL条件下,催化10 min的降解率为63.41%,催化70 min的降解率即可达到99.87%,比未掺杂TiO₂纳米纤维的降解率提高了6.36%,可见,La³⁺的掺杂提高了TiO₂光催化降解速率,所需要的时间减少了。     

树枝状PVDF纳米纤维膜负载TiO2吸附-光催化降解染料废水

通过添加有机支化盐四丁基氯化铵水合物，采用静电纺丝技术制备了以树枝状聚偏氟乙烯(PVDF)纳米纤维膜为载体的二氧化钛(TiO₂)光催化剂，对其表面形貌及结构进行了表征分析，并以罗丹明B为目标污染物，考察了其对染料废水的吸附和光催化降解性能。结果表明，树枝状PVDF纳米纤维膜由直径为310 nm的主干纤维和直径为5～100 nm的分支纤维构成，TiO₂能够均匀分布于主干和分支纤维表面。与常规PVDF纳米纤维膜负载TiO₂光催化剂相比，这种树枝状纳米纤维膜显示出更高的亲水性和比表面积，使其在室温下对水中罗丹明B的平衡吸附量提升了5.4倍；同时该材料也显示出更优异的光催化性能，在紫外光和可见光下对染料的降解速率常数分别提升了1.0倍、2.3倍。     

Al2O3微滤膜的超疏水改性研究

采用多层自组装技术在Al₂O₃微滤膜表面制备TiO₂纳米涂层, 并利用1H,1H,2H,2H-全氟辛基乙基三乙氧基硅烷(PFDS)对其表面进行氟化处理, 获得超疏水改性膜。通过X射线衍射仪, 傅立叶变换红外光谱仪, 原子力显微镜, 水接触角测试仪和扫描电子显微镜对改性膜进行表征。分析了TiO₂纳米涂层的晶型结构, 探讨了TiO₂沉积时间与改性膜表面粗糙度和疏水性之间的关系, 研究了PFDS改性次数对膜表面形貌和疏水性能的影响规律。结果表明: 在600℃退火1 h后, 获得锐钛矿结构的TiO₂纳米涂层。随TiO₂沉积时间的延长, 膜表面粗糙度增大, 水滴在膜表面的接触由Wenzel状态转变为Cassie状态; 当TiO₂沉积时间为50?min, PFDS改性3次时, 获得理想的微纳米二级超疏水表面形貌, 水接触角达到174.5°。     

异质结型BaTiO3/TiO2复合纳米纤维的制备及光催化性能

以静电纺丝技术制备的TiO₂纳米纤维为模板和反应物, 采用水热法原位合成了具有异质结构的BaTiO₃/TiO₂复合纳米纤维。利用X射线衍射(XRD)、扫描电镜(SEM) 和高分辨透射电镜(HRTEM)等分析测试手段对样品的结构和形貌进行表征。结果表明: BaTiO₃纳米微粒均匀地生长在TiO₂纳米纤维表面, 制备了异质结型BaTiO₃/TiO₂复合纳米纤维。材料的光催化性能利用罗丹明B和苯酚的脱色降解反应测试。BaTiO₃/TiO₂复合纳米纤维材料, 在紫外光照射下, 光催化降解活性较纯锐钛矿TiO₂纳米纤维有明显提高, 罗丹明B和苯酚在该复合纳米纤维材料上的光催化降解反应遵循一级反应动力学。且易于分离、回收和再利用, 循环使用5次, 罗丹明B的脱色率仍保持在96%以上。     

CdS、Ag+掺杂改性纳米TiO2光催化降解有机物研究

在理论分析的基础上对纳米TiO₂分别进行掺CdS和掺银改性实验研究。采用XRD和粒度分析技术对改性后的样品进行表征,并以掺杂CdS、Ag⁺纳米TiO₂进行光催化降解甲基橙模拟实验。结果表明,掺杂CdS、Ag⁺纳米TiO₂在可见光范围内降解有机物的效率有较大提高。     

纳米TiO2/碳化植物纤维复合材料的制备与光催化性能

以碳化植物纤维(CPF)为载体,将纳米TiO₂附着于纤维表面,通过浸渍煅烧法和溶剂热法合成纳米TiO₂/CPF复合光催化剂,并对其光催化性能进行了研究。通过SEM、HRTEM、XRD、EDS分析了纳米TiO₂/CPF复合光催化剂的微观结构和化学组成;以光催化降解亚甲基蓝为模型反应,考察复合材料中不同纤维种类和TiO₂负载量对光催化活性的影响。结果表明,在一定范围内随TiO₂负载量的增加,纳米TiO₂/CPF复合材料光催化性能先增强后减弱。纳米TiO₂/CPF复合材料的光催化性能明显提高是由于在TiO₂和碳纤维界面的良好电荷分离能力。降解染料的活性物种有超氧负离子和羟基自由基,但羟基自由基是主要物种。此外,浸渍煅烧法和溶剂热法生成的纳米TiO₂在纤维表面的存在形式不同,浸渍煅烧法生成纳米TiO₂薄膜,包裹纤维;而溶剂热法生成的TiO₂结晶成纳米颗粒,附着于纤维表面。      

纳米TiO2LDPE复合材料包膜控释肥残膜的降解特性

将纳米TiO₂与低密度聚乙烯(LDPE)复合形成包膜液,采用喷动流化床包膜设备制备了纳米TiO₂-LDPE复合材料包膜控释肥.在水浸泡法研究控释肥养分释放特征的基础上,对人工加速老化条件下光照不同时间的控释肥残膜进行失重率测定.采用FT-IR、DSC和黏度法等分析了纳米TiO₂对控释肥残膜光催化降解特性的影响,探讨了残膜在光照前后的分子量和羰基指数等的变化规律.结果表明:光催化剂加入后,控释肥的养分释放速率降低且释放期变长;疏水纳米TiO₂对控释肥残膜的降解具有显著的促进作用,当添加的质量分数为1%时,降解性能最好.随着残膜的降解程度增大,残膜中LDPE的羰基指数和结晶度升高,黏均分子量下降.     

单晶TiN颗粒为前驱体制备TiO2薄膜及其光催化性能（英文）

为了开发高活性的二氧化钛(TiO2)光催化剂,通过简易的两步法制备了TiO2薄膜.首先将钛片放入氮化钛(TiN)纳米颗粒悬浮液中,然后干燥这一体系制得TiN/Ti薄膜,最后通过煅烧TiN薄膜前驱体制备了平整均一的二氧化钛(TiO2)薄膜.通过考察退火温度对样品光吸收性能的影响,确定最优退火温度为500℃.在此条件下制备的TiO2为多晶锐钛矿,吸收边带400 nm.以制备的TiO2薄膜为催化剂,3 h内苯酚的降解率达到88%,远大于使用德固赛TiO2(P25)时的62%,制备的二氧化钛薄膜比P25显示出更优良的光催化性能,其光催化降解苯酚的动力学常数为P25的2.2倍.     

Preparation and photocatalytic activity of nanoglued Sn-doped TiO2

In this paper, Sn-doped TiO(2) photocatalyst was prepared and immobilized on a glass substrate using an about-to-gel SiO(2) sol as a nanoglue. The characterization of the Sn-doped TiO(2) by XRD showed that 5% Sn content is formed by anatase and rutile crystallites. Characterization of the nanoglued photocatalyst by the BET measurement, TEM, and SEM showed that the photocatalyst was a nanoporous material with a high-surface area. The Sn-doped TiO(2) was uniformly dispersed within the three-dimensional network of the silica in the form of nanoparticles. The nanoglued photocatalyst showed high photocatalytic activity during the degradation of penicillin under UV light. The effect of different Sn content on the amount of hydroxyl radical was discussed by using salicylic acid as probe molecules. The results show that an appropriate amount of Sn dopant can greatly increase the amount of hydroxyl radicals generated by TiO(2) nanoparticles, which are responsible for the obvious increase of photocatalytic activity.     

Preparation and characterization of visible-light-driven TiO2 photocatalyst Co-doped with nitrogen and erbium

A series of nitrogen and erbium co-doped TiO2 photocatalyst was prepared by sol-hydrothermal method. The structure and properties of the photocatalyst were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (DRS). The XRD and BET results showed that co-doping inhibited the increase of crystallite size and enlarged specific surface areas. XPS spectroscopy indicated nitrogen atoms were incorporated into TiO2 lattice, and erbium atoms mostly existed in the forms of Er2O3. A shift of the absorption edge to the lower energy and four absorption bands located at 654, 544, 524 and 489 nm attributed to the 4f transitions of 4I15/2 --> 4F2/9, 4I15/2 --> 4S3/2, 4I15/2 --> 2H11/2, 4I15/2 --> 4F7/2 of Er3+ were observed using DRS spectroscopy. The catalytic efficency was evaluated by the photocatalytic degradation of methyl orange (MO) under visible light irradiation. The results showed that the photocatalytic performance of the co-doped TiO2 was related with the hydrothermal temperature and the molar ratio of N/Ti, and they showed higher acitivites than pure TiO2. Results determined by fluorescence technique revealed that irradiation (lambda > 400 nm) of TiO2 photocatalyst dispersed in MO solution induces the generation of the highly active hydroxyl radicals (OH). It indicated the photocatalytic activities of TiO2 photocatalyst were correlation with the formation rate of hydroxyl radicals (OH) and other active oxygen species.     

Immobilization of TiO2 and Fe-C-TiO2 photocatalysts on the cotton material for application in a flow photocatalytic reactor for decomposition of phenol in water

TiO2 and Fe-C-TiO2 photocatalysts have been immobilized on the cotton material and used in a flow photocatalytic reactor for phenol decomposition. The cotton material has been applied as a support for photocatalyst, because can be easily removed and replaced in a reactor, what facilitates the performance of the photocatalytic process. Fe-C-TiO2 photocatalyst has been prepared by modification of TiO2 fine particles of anatase structure with FeC2O4 through heating in Ar at 500 degrees C. The immobilized photocatalysts could efficiently decompose phenol in multiple use, Fe-C-TiO2 showed higher photocatalytic activity than TiO2, around 15-18 mg and 15-16 mg of phenol have been decomposed after 5 h of UV irradiation on Fe-C-TiO2 and TiO2, respectively. After addition of H2O2 the phenol decomposition and the mineralization degree have been accelerated, especially with immobilized Fe-C-TiO2 photocatalyst, in case of that the photo-Fenton reaction occurred. In the presence of H2O2 around 26-28 mg and 21-24 mg of phenol have been decomposed on Fe-C-TiO2 and TiO2 respectively, after 5 h of UV irradiation.     

Deposition of anatase titania onto carbon encapsulated magnetite nanoparticles

A novel magnetically separable photocatalyst (titania-coated carbon encapsulated magnetite: TCCEF) was prepared. The prepared composite photocatalyst was characterized with an x-ray diffractometer (XRD), a transmission electron microscope (TEM), a Fourier transform infrared spectrometer (FT-IR) and a vibrating sample magnetometer (VSM). The photocatalytic activity of the samples was determined by degrading model contaminated water, a phenol aqueous solution. The results were compared with single-phase titania (pure titania and Degussa P25) and Fe(3)O(4)/TiO(2), and enhanced photocatalytic activity was obtained. It is suggested that the enhanced photocatalytic activity is ascribed to two major factors. First, the encapsulation of magnetite into the carbon layer may inhibit the direct electrical contact of titania and magnetite, hence preventing the photodissolution of the iron oxide phase. Second, the enhanced hydroxyl groups on TCCEF may inhibit the recombination of electron-hole pairs. On the other hand, the magnetic photocatalyst can be easily recovered from a slurry with the application of an external magnetic field.     

超临界流体干燥法制备TiO2/ Fe2O3 和TiO2/ Fe2O3/ SiO2 复合纳米粒子及光催化性能

以TiCl₄ 、Fe (NO₃ )₃·9H₂O 和Na₂SiO₃19H₂O 为原料, 采用溶胶凝胶法结合超临界流体干燥法(SCFD)制备了纳米级TiO₂/ Fe₂O₃ 和TiO₂/ Fe₂O₃/ SiO₂ 复合光催化剂。以光催化降解苯酚对所得催化剂的催化活性进行了评价。结果表明, 纳米TiO₂/ Fe₂O₃ 复合粒子与单组分TiO₂ 比较, 复合粒子光催化活性高于单组分的TiO₂, 6h 苯酚降解率高达95.9 %。SiO₂ 的加入可以抑制纳米粒子粒径的长大和晶相的转变, 增强TiO₂ 纳米粒子的热稳定性。复合光催化剂中Fe₂O₃ 最佳掺入量为0.06 %, SiO₂ 最佳掺入量为10 %(摩尔分数) 。并用XRD、TEM 和FTIR 等手段进行了表征。TiO₂ 以锐钛矿型形式存在, SiO₂ 以无定性形式存在。比较了不同制备方法制得的TiO₂/ Fe₂O₃ 复合光催化剂, 得出超临界干燥法制备的光催化剂具有粒径小、比表面积大、分散性好、光催化活性高等特点。采用超临界流体干燥可直接得锐钛型纳米复合光催化剂。     

A visible light response TiO2 photocatalyst realized by cationic S-doping and its application for phenol degradation

S-doped TiO2 photocatalyst with high visible light activity was prepared by acid catalyzed hydrolysis method using thiourea (TU) as sulfur source. The catalyst was characterized by DRS, XPS, XRD, FTIR, SEM and N2 adsorption. It was found that cation S6+ was homogeneously incorporated into the bulk phase of TiO2 and substitutes for some of the lattice titanium (Ti4+). Doped S can form a new band above the valence band and narrow the band-gap of the photocatalyst, giving rise to a second absorption edge in the visible light region. The activity of the catalyst was examined by photodegradation of phenol in aqueous solution under both artificial visible light and solar light irradiation. The activity of catalyst was found to be dependent on the doping amount of S and the maximum activity was observed when the catalyst was obtained by calcinated at 600 degrees C with the mass ratio of TU/TiO2=1. Too much of new-generated band-gap structures due to higher S-doping could act as recombination centers for electron-hole pairs. Catalyst with optimum S-doping exhibited the highest activity under both artificial light and solar irradiation for phenol degradation. In addition, doped S also beneficial for the better dispersion, large S(BET) and phase transformation retardation of TiO2.     

Synthesis and characterization of the N-doped TiO2 photocatalyst for the photodegradation of methylene blue and phenol

To extend the light absorption of TiO2-based photocatalysts towards the visible-light range and to eliminate the rapid recombination of excited electrons/holes during photoreaction, a new type of photocatalyst (N-doped TiO2) powder was prepared through a simple sol-gel process. The crystal phase composition, structure, and light absorption of the new photocatalyst were comprehensively examined via X-ray diffraction, ultraviolet-visible (UV-Vis) absorption spectroscopy, and atomic-absorption spectroscopy. The photo-oxidation efficiency of the photocatalyst was also evaluated in the photodegradation of methylene blue (MB) and of phenol in aqueous solutions under visible-light irradiation from a neon lamp (lambda > 400 nm). The results of the analyses that were performed in this study indicated that the N-doped TiO2 could eliminate the electron/holes recombination and could increase the light absorption in the visible range. The results of the analysis of the UV-Vis diffuse reflection and optical-absorption spectra indicated that a new energy level below 3.2 eV generated in the N-doped TiO2 promoted the optical absorption in the visible-light region and made visible-light excitation possible (E < 3.2 eV). The experiment demonstrated that the photo-oxidation efficiency of MB when N-doped TiO2 powder was used was significantly higher than that when the conventional TiO2 powders were used. The development of such photocatalyst may be considered a breakthrough in the large-scale utilization of solar energy to address the current and future environmental needs.     

Synthesis and photo-degradation application of WO3/TiO2 hollow spheres

A WO(3)/TiO(2) composite, hollow-sphere photocatalyst with average diameter of 320 nm and shell thickness of 50 nm was successfully prepared using a template method. UV-vis diffuse reflectance spectra illustrated that the main absorption edges of the WO(3)/TiO(2) hollow spheres were red-shifted compared to the TiO(2) hollow spheres, indicating an extension of light absorption into the visible region of the composite photocatalyst. The WO(3) and TiO(2) phases were confirmed by X-ray diffraction analysis. BET isotherms revealed that the specific surface area and average pore diameter of the hollow spheres were 40.95 m(2)/g and 19 nm, respectively. Photocatalytic experiments indicate that 78% MB was degraded by WO(3)/TiO(2) hollow spheres under visible light within 80 min. Under the same conditions, only 24% MB can be photodegraded by TiO(2). The photocatalytic mineralization of MB, catalyzed by TiO(2) and WO(3)/TiO(2), proceeded at a significantly higher rate under UV irradiation than that under visible light, and more significant was the increase in the apparent rate constant with the WO(3)/TiO(2) composite semiconductor material which was 3.2- and 3.5-fold higher than with the TiO(2) material under both UV and visible light irradiation. The increased photocatalytic activity of the coupled nanocomposites was attributed to photoelectron/hole separation efficiency and the extension of the wavelength range of photoexcitation.     

TiO2-N-S光催化剂的制备、表征及性能研究

以胱氨酸为掺杂剂,利用溶胶-凝胶法直接制备了N、S共掺杂改性的光催化剂TiO2-N-S,借助XRD、XPS和SPS等手段对其进行了表征,并以苯酚为模型污染物考察了其在模拟太阳光下的催化活性.XRD分析表明该光催化剂为锐钛矿晶型,N、S共掺杂能有效抑制TiO2晶粒的生长,提高了晶相间转变温度.XPS显示S是以S6+形式存...