V掺杂TiO2纳米管阵列的制备及光催化研究

以钒钛合金为原料,应用阳极氧化法制备出高度致密、有序的V掺杂TiO2纳米管阵列。应用扫描电镜(SEM)和粉末X光衍射仪(XRD)表征分析纳米管阵列的形貌和结构,结果表明在浓度不同的HF电解液下制备出径向不同的纳米管阵列,电解液浓度(0.5%～1.5%(质量分数)),管径变化(39.7～72.7nm)。在室温、可见光照射条件下,以10mg/L的亚甲基蓝溶液为模拟污染物进行光催化降解试验,研究了其光催化性能。结果显示V掺杂TiO2纳米管阵列光催化性能优于纯TiO2纳米管,且在HF电解液浓度为1.0%(质量分数)时制备出来的TiO2纳米管光催化降解有机毒物性能最佳。     

TiO2纳米管阵列膜的制备及对304不锈钢的光生阴极保护效应

应用电化学阳极氧化法在Ti表面构筑不同的TiO2纳米管阵列膜。采用XRD、SEM、XPS表征薄膜的结构、形貌和组成。通过电化学阻抗谱及电位随时间变化的测试,考察TiO2薄膜的光生阴极保护效应。结果表明薄膜主要由锐钛矿型的TiO2纳米管阵列组成,当304不锈钢耦连于紫外光照下的TiO2薄膜电极时,其界面反应电阻变小,电极电位显著降低,说明TiO2纳米管薄膜能够对不锈钢产生良好光生阴极保护效应,特别是掺Fe的TiO2薄膜在光照时可使不锈钢电位降低约450mV,而且在暗态时也能较长时间保持对不锈钢的阴极保护作用。     

TiO_2纳米管半导体特性与光电催化动力学研究

通过阳极氧化法在有机溶液中制备TiO2纳米管阵列,随着氧化时间的不同,TiO2纳米管阵列呈现各异的形貌。通过光电流测试,考察了不同氧化时间和施加不同电压下的Ti/TiO2纳米管阵列光电极的光电化学响应,阳极氧化6h表面规整纳米管阵列并施加偏压0.1V光电流响应最强。通过测试Mott-Schott-ky曲线,计算不同氧化时间的TiO2纳米管阵列的半导体载流子浓度、平带电位、空间电荷层宽度和能带弯曲量等特征参数,理论上提出了TiO2纳米管阵列生长机理。在光电催化降解无机氨氮的实验中,所得到的电化学阻抗谱(EIS)表明,外加偏压0.1V时,TiO2纳米管阵列电极的光电催化活性最强,同时通过拟合电路分析可知,光电催化降低了电极界面的反应阻抗,加速了光生载流子的转移,在TiO2纳米管阵列电极/溶液界面Helmholtz层中发生的氧化还原反应是整个光电催化反应的速率控制步骤。     

TiO_2纳米管阵列的制备及其光电化学性质研究

以H3PO4/NH4F水溶液为电解液,在20V下阳极氧化钛片1h制得TiO2纳米管阵列,其管径约为100nm,管长约800nm。经不同温度煅烧后,利用FESEM、XRD和光电化学分析测试系统分别对纳米管阵列的形貌结构、晶相组成以及光电化学性质进行研究。光电化学特性研究结果表明600℃热处理后性能最佳。当前体系中所制备的薄膜结构上高度有序,光电化学性质优良,作为光电极材料在太阳能光电转换、光催化等领域具有广阔的应用前景。     

无定型态TiO_2纳米管的光致亲水性能研究

采用阳极氧化法在钛片表面制备了无定型态的Ti O2纳米管,并通过扫描电子显微镜(SEM)对其表面形貌进行了表征。采用JGW-360A型接触角测量仪测量蒸馏水在Ti O2纳米管上的接触角,研究了光照时间、管径尺寸、管长等因素对纳米管亲水程度的影响。结果表明:无定型态Ti O2纳米管在25 W紫外光照条件下,具有优异的超亲水性能;管径尺寸对亲水性的影响不大;管长增加幅度越大,亲水性提高越显著。     

玻璃基底TiO2纳米管阵列的制备及其光电性能研究

提高二氧化钛纳米管阵列电极的机械稳定性,改善电极的透光性能,有助于提高其光电催化性能,拓展电极的应用范围.通过室温射频溅射方法在玻璃基底上溅射一层金属钛膜,然后在含0.5%HF的电解液,10V阳极氧化电压下进行阳极氧化,得到玻璃基TiO2纳米管阵列电极.扫描电子显微镜和X射线衍射分析表明,玻璃基表面形成了孔径为20～30nm,管长约130nm排列有序的锐钛矿型TiO2纳米管阵列.光电性能测试表明,玻璃基TiO2纳米管阵列与金属钛基TiO2纳米管阵列表现出相似的光电催化性能,明显优于磁控溅射制备的TiO2薄膜.     

TiO2纳米管阵列薄膜的水热晶化

首先在KF和乙二醇的混合溶液中利用阳极氧化技术在钛基底表面制得了一层排列整齐、形貌均一的TiO₂纳米管阵列薄膜,然后将制得的薄膜进行水热处理,通过扫描电子显微镜、X射线衍射仪等表征手段研究了水热处理温度和时间对TiO₂纳米管阵列薄膜表面形貌、结晶度以及管状结构的影响。结果表明:水热处理即使在较短的时间内（如3 h）也可在较低温度下（如210℃）使TiO₂纳米管阵列薄膜由无定形转变为锐钛矿型结构;提高水热处理温度或延长水热处理时间均可提高薄膜的结晶度,但同时纳米管管壁结晶度增加会使管内径变小甚至堵塞,从而破坏管状结构。     

TiO2/石墨烯复合物的制备及其嵌脱锂行为研究

以钛酸丁酯为TiO₂前驱体, 通过水热法制得TiO₂/石墨烯复合物。使用X射线衍射(XRD)、热重分析(TG)、透射电镜(TEM)、扫描电镜(SEM)和电化学充放电等手段对材料进行了表征和分析。结果表明: TiO₂颗粒均匀地分散在石墨烯的表面, 复合物中石墨烯的含量为24.67%。当该材料用作锂离子电池负极材料时, 在2C的放电倍率下, 首次放电容量为384.35 mAh/g, 循环100次后的放电容量为130.26 mAh/g, 是纯TiO₂电极放电容量的2.93倍。与纯TiO₂电极相比, TiO₂/石墨烯复合物的电荷转移电阻较低。TiO₂/石墨烯复合物具有较好的倍率性能和较高的电化学反应活性。     

Surface Modification of Fe7S8/C Anode via Ultrathin Amorphous TiO2 Layer for Enhanced Sodium Storage Performance

Iron sulfides with high theoretical capacity and low cost have attracted extensive attention as anode materials for sodium ion batteries. However, the inferior electrical conductivity and devastating volume change and interface instability have largely hindered their practical electrochemical properties. Here, ultrathin amorphous TiO₂ layer is constructed on the surface of a metal–organic framework derived porous Fe₇S₈/C electrode via a facile atomic layer deposition strategy. By virtue of the porous structure and enhanced conductivity of the Fe₇S₈/C, the electroactive TiO₂ layer is expected to effectively improve the electrode interface stability and structure integrity of the electrode. As a result, the TiO₂‐modified Fe₇S₈/C anode exhibits significant performance improvement for sodium‐ion batteries. The optimal TiO₂‐modified Fe₇S₈/C electrode delivers reversible capacity of 423.3 mA h g^?1 after 200 cycles with high capacity retention of 75.3% at 0.2 C. Meanwhile, the TiO₂ coating is conducive to construct favorable solid electrolyte interphase, leading to much enhanced initial Coulombic efficiency from 66.9% to 72.3%. The remarkable improvement suggests that the interphase modification holds great promise for high‐performance metal sulfide‐based anode materials for sodium‐ion batteries.     

Photoelectrochemical properties of TiO2 nanotube arrays: effect of electrolyte pH and annealing temperature

The effect of electrolyte pH and annealing temperature on the formation of TiO₂ nanotube arrays in connection with the photoelectrochemical response was investigated in this article. Well-aligned TiO₂ nanotube arrays were fabricated by anodisation of Ti foil in an electrolyte consisting of 1?M of glycerol (85?wt% of glycerol and 15?wt% of water) with 0.5?wt% of NH₄F at 30?V for 30?min. The pH of the electrolyte was varied from pH 1 to 7. With the increase of electrolyte pH to neutral condition, the length of the nanotube arrays was increased from ～320 to 1100?nm. As-anodised TiO₂ nanotube arrays were amorphous in nature. However, anatase phase was observed after annealing at 400°C and polycrystalline anatase and rutile phase could be observed by heating up to 500°C in air atmosphere. Based on the results obtained, the length and crystalline phases of TiO₂ nanotube arrays affect the performance of photoelectrochemical response and photoconversion efficiency significantly.     

F掺杂TiO2纳米管阵列的可见光催化活性和电子结构

采用电化学阳极氧化法,在纯Ti表面一步制得原位生长的F掺杂TiO2纳米管阵列.对煅烧后样品进行扫描电镜(SEM)、X射线多晶衍射(XRD)表征.结果表明,所得TiO2纳米管排列整齐、平均管径约40 nm,平均管长约700 nm.XPS蚀刻分析发现,少量F原子以F-Ti-O键的形式掺杂进了TiO2晶格,同时产生活性物质T...     

Identifying the Origin and Contribution of Surface Storage in TiO2(B) Nanotube Electrode by In Situ Dynamic Valence State Monitoring

Fundamental insight into the surface charging mechanism of TiO₂(B) nanomaterials is limited due to the complicated nature of lithiation behavior, as well as the limitations of available characterization tools that can directly probe surface charging process. Here, an in situ approach is reported to monitor the dynamic valence state of TiO₂(B) nanotube electrodes, which utilizes in situ X‐ray absorption spectroscopy (XAS) to identify the origin and contribution of surface storage. A real‐time correlation is elucidated between the rate‐dependent electrode performance and dynamic Ti valence‐state change. A continuous Ti valence state change is directly observed through the whole charging/discharging process regardless of charging rates, which proves that along with the well‐known non‐faradaic reaction, the surface charging process also originates from a faradaic reaction. The quantification of these two surface storage contributions at different charging rates is further realized through in situ dynamic valence state monitoring combined with traditional cyclic voltammetry measurement. The methodology reported here can also be applied to other electrode materials for the real‐time probing of valence state change during electrochemical reactions, the quantification of the faradaic and non‐faradaic reactions, and the eventual elucidation of electrochemical surface charging mechanisms.     

钠离子电池TiO_2/还原氧化石墨烯负极材料的制备及储钠性能

由于钠离子半径比锂离子半径大70%,使得钠离子在石墨电极材料中脱嵌较困难,需要对石墨负极材料进行改性。以天然石墨为原料,采用Hummers法制备氧化石墨烯;在此基础上以钛酸丁酯为原料,采用溶胶-凝胶法制备了TiO_2前驱体/氧化石墨烯(TiO_2/GO)复合材料,通过热处理获得锐钛矿型TiO_2/还原氧化石墨烯(TiO_2/RGO)复合材料。电化学测试结果表明:TiO_2含量为15wt%的TiO_2/RGO复合材料在电流密度为20mA·g~(-1)下的首次放电比容量为74.08mAh·g~(-1),随着循环次数的增加,放电比容量逐渐增大,循环50次后达109.10mAh·g~(-1);充放电效率也呈现出逐渐增大的趋势,循环50次后达65.59%。而纯还原氧化石墨烯首次放电比容量为41.43mAh·g~(-1),循环50次后仅为20.47mAh·g~(-1)。     

低温制备锐钛矿型TiO2溶胶的性能研究

采用溶胶-凝胶法,以水为溶剂,在低于70℃下直接合成纳米锐钛矿型TiO2溶胶,研究了反应温度、pH值对溶胶晶型、晶粒大小和稳定性的影响.以不同光照下对亚甲基蓝的降解,评价了溶胶的光催化活性.结果表明:较低pH值下溶胶中的TiO2出现了金红石相与锐钛矿相组成的混晶相,而pH值相对较高时则得到纯锐钛矿相TiO2;在紫外光、日光灯和太阳光下,与P25对亚甲基蓝的降解相比,同等条件下所制备的TiO2溶胶显示出更好的光催化活性;混晶相TiO2溶胶的光催化性优于纯锐钛矿相TiO2溶胶.     

Study on the Phase Transformation Behavior of Nanosized Amorphous TiO2

Nanosized amorphous TiO2 powders with a specific surface area of 501 m^2.g^-1 were prepared by hydrolysis. After calcined at 400℃ for 2 h, the prepared amorphous TiO2 powders were fully transformed into anatase crystallites with a specific surface area of 141 m^2.g^-1. Differential scanning calorimetric (DSC) experiments were performed on the samples of nanosized amorphous TiO2 mixed with microsized anatase, nanosized anatase, or nanosized α-Al2O3 respectively. Effects of sample packing, anatase addition, or α-Al2O3 addition on the crystallization behavior of nanosized amorphous TiO2 were analyzed.     

Composite of Carboxyl-Modified Multi-walled Carbon Nanotubes and TiO2 Nanoparticles: Preparation and Photocatalytic Activity

The composite of carboxyl-modified multi-walled carbon nanotubes (MWNT-COOHs) and TiO₂ nanoparticles was prepared by improved solvothermal process. X-ray diffraction (XRD), transmission electron microscope (TEM) and UV-Vis spectra were used to characterize the products. The results show that MWNT-COOHs were “welded” by the TiO₂ nanoparticles attached to the open ends of MWNT-COOHs. Compared with pure TiO₂ nanoparticles, the composite displays higher photocatalytic activity with 99.9% of degradation ratio of copper sulfophthalocyanine after 3 h irradiation.     

Sm掺杂对锐钛矿TiO2电子寿命和红移影响的第一原理研究

基于密度泛函理论平面波超软赝势方法,采用第一性原理对不同浓度Sm掺杂锐钛矿相TiO2超胞的结构优化、形成能、能带结构、态密度、差分电荷分布和光学性质进行了计算。结果表明Sm掺杂后锐钛矿相TiO2超胞的电子结构变化很大。在限定的浓度范围内,掺杂浓度越小,形成能越小,掺杂越容易,电子寿命越长,带隙宽度越窄,吸收光谱红移越显著。计算结果与实验结果一致。     

N掺杂TiO2材料可见光光催化性能研究进展

概括了最近报道的N掺杂TiO2可见光光催化材料的研究成果，其中包括样品制备的进展、掺杂机理的研究和可见光响应理论的研究。在制样方法方面，分析了不同方法制备的样品在性能上的特点和差异；在掺杂机理研究方面，归纳了目前研究中对N掺杂TiO2机理的不同观点，包括N在TiO2晶格中的位置以及N掺入后对TiO2半导体能级结构的影响；最后详细介绍了几种N掺杂TiO2可见光响应理论。     

水热法制备钛酸盐纳米管的研究进展

作为一种有诱人前景的新材料,钛酸盐纳米管的研制开发正在国内外展开.介绍了钛酸盐纳米管的微观结构和形成机理;综述了目前最为常见的钛酸盐纳米管的合成方法--水热法以及水热法制备钛酸盐纳米管的诸多影响因素:NaOH的浓度、反应时间和反应温度等;简要介绍了钛酸盐纳米管的应用.     

不同制备条件对二氧化钛纳米管阵列及其结构的影响

采用阳极氧化法以NH4F/乙二醇为电解液制备高度有序的TiO2纳米管,研究了不同电解液浓度、电解电压、电解时间等参数对TiO2纳米管的影响.在不同温度下对TiO2纳米管进行退火处理.分别利用转靶X射线衍射仪(XRD)和场发射扫描电子显微镜(SEM)对TiO2纳米管阵列的物相结构和形貌变化进行表征.结合氧化过程电流密度变...