阳极氧化制备TiO2纳米管及其光催化性能

采用电化学阳极氧化法在纯Ti表面制备出结构整齐有序的TiO₂纳米管阵列, 研究了不同溶液体系对TiO₂纳米管尺寸和形貌的影响. 利用X射线衍射仪和场发射扫描电镜表征所制备的TiO₂纳米管. 20 V反应15 h, 0.5 wt% HF＋1 mol/L (NH₄)H₂PO₄溶液中TiO₂纳米管直径为70～90 nm, 长度约2.2 μm, 在500 ℃的空气气氛下退火1 h, 纳米管薄膜以锐钛矿结构为主, 在该条件下所制备TiO₂纳米管的光电流密度达到3.2 mA/cm². 以该纳米管薄膜为光阳极, 施加0.45 V (vs. SCE)的外加偏压, 在125 W紫外光照射5 h后, 初始摩尔浓度为20×10^－6 mol/L的酸性红G (C₁₈H₁₃N₃Na₂₀₈S₂)在pH＝3时, 降解率达到92.4%.     

LaNiO3/TiO2纳米管阵列的电化学制备及其光催化性能

利用脉冲电沉积与高温退火相结合的方法制备了镍酸镧(LaNiO₃)纳米颗粒负载的二氧化钛(TiO₂)纳米管阵列. 修饰于TiO₂纳米管阵列上的LaNiO₃纳米颗粒粒径小（< 10 nm）、分布均匀、负载量可控,一些LaNiO₃纳米颗粒沉积于TiO₂纳米管内. 紫外可见吸收光谱显示,LaNiO₃/TiO₂纳米管阵列的吸收带边较TiO₂纳米管阵列明显红移,可见光吸收明显增强. 可见光下光催化降解罗丹明B（RhB）的结果表明,脉冲循环沉积500次制得的LaNiO₃/TiO₂纳米管阵列的光催化活性最佳,其对RhB光催化降解速率是TiO₂纳米管阵列的3.5倍,并且表现出极好的光催化稳定性.     

RGO-TiO2纳米管阵列的制备及其光电性能

采用阳极氧化的方法,通过调节阴、阳两电极间距制备不同壁厚的TiO₂纳米管阵列. 采用脉冲电还原沉积的方法将RGO负载于TiO₂纳米管阵列表面合成了RGO-TiO₂纳米管阵列. 相较于负载在薄壁TiO₂纳米管阵列上的RGO,负载于厚壁TiO₂纳米管阵列上的RGO得以充分还原,覆盖率大幅度提高,并显示出良好的光吸收性质和较低的电荷传输电阻,光电流大幅度增加.     

电镀法制备Pt/TiO2纳米管电极及其电催化析氢性能

采用阳极氧化法制备得到锐钛矿型二氧化钛(TiO₂)纳米管阵列,在其表面通过电镀法沉积Pt,得到了低铂的Pt/TiO₂纳米管电极(Pt/TiO₂?NTs)。通过扫描电子显微镜和透射电子显微镜对其进行形貌表征后发现,Pt较为均匀地分布于TiO₂纳米管阵列中。进一步的电催化析氢结果表明,Pb/TiO₂?NTs在10 mA·cm^-2时,过电位为0.079 V,塔菲尔斜率为42.7 mV·dec-1,较Pt/TiO₂致密膜电极(Pt/TiO₂?F)以及商业Pt/C催化剂显示了更为优异的催化活性。同时,在长循环稳定性测试(3000个周期)中,Pb/TiO₂?NTs相较于上述2种对比电极显示了更为优异的稳定性。     

阳极氧化TiO2纳米管阵列调控与应用研究进展

简述了阳极氧化TiO₂纳米管阵列(titanium oxide nanotube array,TNAs)的形成机制，在光催化、传感器、生物医用和太阳能电池等领域的研究进展，详细介绍阳极氧化工艺参数(如电压、温度、时间、pH值、氟离子和添加剂等)对TNAs阵列形态结构的影响。对目前的研究进展进行了展望，并对未来的研究提出了建议。     

NiO/TiO2异质结构纳米管阵列膜对不锈钢的光生阴极保护及其储能性能

本工作通过修饰TiO₂制备半导体复合膜,提高其光吸收和光电化学性能,以期应用于光生阴极保护。先采用阳极氧化法在Ti表面制备TiO₂纳米管阵列膜,再应用水热处理法在膜表面沉积NiO纳米颗粒,形成具有异质结构纳米管复合膜。利用扫描电子显微镜、X-射线衍射、X-射线光电子能谱、紫外-可见吸收光谱、光致发光谱和光电化学技术对制备的纳米膜进行表征。结果表明,与纯TiO₂纳米管膜比较,NiO/TiO₂纳米管复合膜的光吸收扩展到可见光区。白光照射下,其在0.5 mol·L^?1 KOH和1 mol·L^?1 CH3OH混合液中的光电流密度达到176μA·cm^?2,是纯TiO₂纳米管膜的2倍。复合膜具有良好的光生阴极保护作用,与0.5 mol·L^?1 NaCl溶液中的403不锈钢耦连后,可使其电极电位下降440 mV,在光照2.5 h再转为暗态后,因具有电荷储存能力还可继续提供约15.5 h的阴极保护效应。     

基于纳米TiO2和TiN为工作电极的循环伏安法测定过氧化氢的含量

制备了纳米TiO₂、TiN材料,将其作为工作电极,建立了循环伏安法测定过氧化氢含量的方法。将钛片置于含10.0 g氟化铵、0.6 g脲、24 mL 30%（质量分数）过氧化氢溶液、24 mL硝酸组成的抛光液中进行下表面抛光处理,再加入15 mL丙酮、15 mL无水乙醇、15 mL水,超声处理15 min后,得到光亮钛片。以光亮钛片为阳极,普通钛片为阴极,在不同电解质[TiO₂粗糙膜对应的电解质为1.0 mol·L^-1硫酸溶液;TiO₂纳米管为50 mL丙三醇、50 mL水、0.2 mol·L^-1硫酸溶液、0.5%（质量分数）氟化钠溶液;TiO₂纳米孔为100 mL乙二醇、1 mL水、0.38%（质量分数）氟化铵溶液]中,采用阳极氧化法,得到不同形貌大小的TiO₂粗糙膜、TiO₂纳米管、TiO₂纳米孔;再通过氨气热还原,得到TiN粗糙膜、TiN纳米管、TiN纳米孔。以TiO₂     

阳极氧化TiO2纳米管阵列的制备与掺杂*

近年来,TiO₂纳米管阵列的制备与应用得到了广泛的研究。阳极氧化法制备TiO₂纳米管阵列具有工艺简单、成本低廉、易于放大等优点,引起了极大关注。本文综述了阳极氧化法制备TiO₂纳米管阵列的研究现状,基于TiO₂纳米管阵列在阳极氧化过程中的生长机理,讨论了决定阳极氧化TiO₂纳米管阵列形成的主要因素。结合本组的研究工作,总结了如何通过改变电压、升压速率、电解液、温度和氧化时间,实现纳米管管径、管壁厚度、管长的有效控制,提高TiO₂纳米管阵列的表面形貌质量。最后介绍了TiO₂纳米管阵列掺杂改性方面的研究进展。     

纳米管TiO2光催化降解丙烯的研究

制备了纳米管TiO₂并研究了不同pH和不同处理温度对纳米管TiO₂光催化氧化丙烯的影响,采用能量色散分析、荧光光谱和X射线衍射谱等方法对影响因素进行了初步探讨.     

锰离子控制掺杂二氧化钛薄膜光催化活性增强的机理探讨

采用溶胶-凝胶法通过工艺控制制备了锰离子以不同形式掺杂TiO₂的光催化剂薄膜,并通过XPS和SEM对薄膜的结构进行表征.通过UV-Vis分光光度计及电化学工作站表征了薄膜的光吸收性能和光电化学性能,通过甲基橙溶液的光催化降解脱色率来表征催化剂薄膜的光催化活性.结果表明,以锰离子MT掺杂方式制备的TiO₂薄膜可明显增强TiO₂的光催化活性,而以MM掺杂方式制备的TiO₂薄膜反而降低了TiO₂的光催化活性;锰离子MT掺杂方式的最佳掺杂质量分数为0.8%.催化剂薄膜的电化学行为显示,薄膜具有p-n结的电容-电压特性,锰离子MT掺杂TiO₂薄膜的开路电位和瞬时光电流信号较强,说明其光生载流子易于生成并且分离效果较好.依据半导体的p-n结原理探讨了锰离子控制掺杂TiO₂的光催化活性机理.     

Design of highly ordered Ag-SrTiO3 nanotube arrays for photocatalytic degradation of methyl orange

Ag-SrTiO₃ nanotube arrays were successfully prepared for the degradation of methyl orange (MO) under ultraviolet irradiation. In order to form highly ordered SrTiO₃ nanotube arrays, the preparation of TiO₂ nanotube arrays by anodic oxidation of titanium foil in different electrolytes was investigated. The selected organic solvents in electrolytes include glycerol, dimethyl sulfoxide and glycol. The results indicate that the morphology of TiO₂ nanotube arrays prepared in glycol containing ammonium fluoride electrolyte is more regular. Then SrTiO₃ nanotube arrays were synthesized by a hydrothermal method using TiO₂ nanotube arrays as the precursor. In order to further improve the photocatalytic activity of SrTiO₃ nanotube arrays, Ag nanoparticles were loaded on SrTiO₃ nanotube arrays by two sets of experiments. The loaded Ag results in an enhancement of photocatalytic activity of SrTiO₃ nanotube arrays. Moreover, the effect of pH on the photocatalytic degradation of MO was also studied.     

Fe2O3/TiO2纳米管阵列的制备及其光催化性能

在钛基体上采用阳极氧化法制备了TiO₂纳米管阵列,采用化学浴方法在TiO₂纳米管阵列上修饰了Fe₂O₃纳米颗粒.利用扫描电镜、X射线衍射和紫外可见漫反射光谱等手段对材料进行了表征,同时测试了材料的光电化学性能及其光催化降解亚甲基蓝染料废水的性能.结果表明,Fe₂O₃纳米颗粒的修饰将TiO₂纳米管阵列的光响应拓宽至可见光区域,提高了光电流,Fe₂O₃/TiO₂纳米管阵列的光电流是未修饰的TiO₂纳米管阵列的9倍.而在光催化反应中,亚甲基蓝最高降解率可达80%,比未修饰的TiO₂纳米管阵列高出30%.     

Fe_2O_3/TiO_2纳米管阵列的制备及其光催化性能

在钛基体上采用阳极氧化法制备了TiO2纳米管阵列,采用化学浴方法在TiO2纳米管阵列上修饰了Fe2O3纳米颗粒。利用扫描电镜、X射线衍射和紫外可见漫反射光谱等手段对材料进行了表征,同时测试了材料的光电化学性能及其光催化降解亚甲基蓝染料废水的性能。结果表明,Fe2O3纳米颗粒的修饰将TiO2纳米管阵列的光响应拓宽至可见光区域,提高了光电流,Fe2O3/TiO2纳米管阵列的光电流是未修饰的TiO2纳米管阵列的9倍。而在光催化反应中,亚甲基蓝最高降解率可达80%,比未修饰的TiO2纳米管阵列高出30%。     

Effect of dopant concentration on photocatalytic activity of TiO2 film doped by Mn non-uniformly

The thin films of TiO₂ doped by Mn non-uniformly were prepared by sol-gel method under process control. In our preceding study, we investigated in detail, the effect of doping mode on the photocatalytic activity of TiO₂ films showing that Mn non-uniform doping can greatly enhance the activity. In this study we looked at the effect of doping concentration on the photocatalytic activity of the TiO₂ films. In this paper, the thin films were characterized by UV-vis spectrophotometer and electrochemical workstation. The activity of the photocatalyst was also evaluated by photocatalytic degradation rate of aqueous methyl orange under UV radiation. The results illustrate that the TiO₂ thin film doped by Mn non-uniformly at the optimal dopant concentration (0.7 at %) is of the highest activity, and on the contrary, the activity of those doped uniformly is decreased. As a comparison, in 80 min, the degradation rate of methyl orange is 62 %, 12 % and 34 % for Mn non-uniform doping film (0.7 at %), the uniform doping film (0.7 at %) and pure titanium dioxide film, respectively. We have seen that, for the doping and the pure TiO₂ films, the stronger signals of open circuit potential and transient photocurrent, the better photocatalytic activity. We also discusse the effect of dopant concentration on the photocatalytic activity of the TiO₂ films in terms of effective separation of the photon-generated carriers in the semiconductor.     

TiO2纳米管阵列覆盖Si薄膜光催化还原CO2性能的研究

本工作采用CVD法在阳极氧化TiO2纳米管阵列膜表面沉积一层非晶Si膜,通过退火后得到晶化了的Si膜/TiO2纳米管阵列的复合结构,并初步就其光催化还原CO2制备碳氢化合物的活性进行研究。拉曼光谱(Raman)、X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、高分辨透射电子显微镜(TEM)等微结构表征结果表明所制备的TiO2纳米管阵列的厚度为270 nm左右,管直径约为70 nm,管壁厚度约为16 nm。覆盖的Si膜已晶化,其厚度约为300 nm。通过高效液相色谱(HPLC)及总有机碳(TOC)来检测光催化还原液相产物中的甲酸及总有机碳含量,发现负载Si膜后的TiO2纳米管阵列光催化性能有所提高,在装有400cut滤光片氙灯照射2 h下TOC含量从21.2 mg.L-1增长到29.5 mg.L-1,表明Si与TiO2的复合可有效的提高光催化还原CO2的活性,这可能与该异质结结构可增加对光的吸收并且可降低光生空穴-电子对复合有关。光催化循环实验表明所制得的催化剂在循环5次后仍可保持91.6%的催化活性。     

Preparation and characterization of Zr doped TiO2 nanotube arrays on the titanium sheet and their enhanced photocatalytic activity

This paper described a new method for the preparation of Zr doped TiO₂ nanotube arrays by electrochemical method. TiO₂ nanotube arrays were prepared by anodization with titanium anode and platinum cathode. Afterwards, the formed TiO₂ nanotube arrays and Pt were used as cathode and anode, respectively, for preparation of Zr/TiO₂ nanotube arrays in the electrolyte of 0.1 M Zr(NO₃)₄ with different voltage and post-calcination process. The nanotube arrays were characterized by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and UV-Vis diffusion reflection spectra (DRS). The photocatalytic activities of these nanotubes were investigated with Rhodamine B as the model pollutant and the results demonstrated that the photocatalytic efficiency of Zr doped TiO₂ nanotubes was much better than that of TiO₂ nanotubes under UV irradiation. Zr/TiO₂ nanotube arrays doped at 7 V and calcined at 600 °C (denoted as TiO₂-7 V-600) achieved the best photocatalytic efficiency and the most optimal doping ratio was 0.047 (Zr/Ti). TiO₂-7 V-600 could be reused for more than 20 times and maintained good photocatalytic activities.     

Preparation and Characterization of Bismuth Doped TiO2 Thin Films

A series of Bismuth-doped titanium oxide (Bi-doped TiO₂) thin films on glass substrates have been prepared by sol-gel dip coating process. The prepared catalysts were characterized by XRD and XPS. The photocatlytic activity of the thin film catalysts was evaluated through the photodegradation of aqueous methyl orange under UV illumination. The experiments demonstrated that the Bi-doped TiO₂ prepared was anatase phase. The doped bismuth was in the 3⁺ oxidation state. The presence of Bi significantly enhanced the photocatalytic activity of TiO₂ films. At calcination temperature of 500°C, with doping concentration of 2 wt %, Bi-doped TiO₂ thin film showed the highest photocatalyic activity.     

The Synthesis and Photocatalytic Properties of TiO2 Nanotube Array by Starch‐Modified Anodic Oxidation

In this study, the characterization and photocatalytic activity of TiO₂ nanotube arrays prepared by anodization process with starch addition were investigated in detail. The results suggested that the optimum mass fraction of starch added in anodization process was 0.1%, with which TiO₂ nanotube arrays owning good tubular structure were synthesized. The tube length and average inner diameter of nanotubes were approximately 4 μm and 30 nm, respectively. Through the characterization of TiO₂ nanotube arrays by energy dispersive spectrometer, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Fourier Transform Infrared (FTIR) spectroscopy, it was found that the as‐prepared nanotubes possessed well uniformed and higher photodegradation responsive than the pure TiO₂. Moreover, it was expected that the as‐prepared nanotubes exhibited good photocatalytic activity for the degradation of RhB under UV‐light irradiation, which could be ascribed to their good morphology, enhanced UV‐light absorption property and electron transmission ability during the photocatalytic reaction. In addition, the nanotubes were not significantly regenerated during the cycling runs experiment. Overall, this study could provide a principle method to synthesize TiO₂ nanotube arrays with enhanced photocatalytic activity by anodization process with starch addition for environmental purification.     

Electrochemically assisted photocatalysis on self-organized TiO2 nanotubes

In this work we investigate influence of an externally applied bias on the photocatalytic performance of self-organized TiO₂ nanotube layers. These layers were grown by anodization of titanium in fluoride containing electrolytes and have different geometric dimensions. Since the layers are grown directly on the Ti substrate, a very good electrical backside contact is directly provided. Therefore, we use the nanotube layers/Ti structures as photo-anodes for the UV light induced photocatalytic decomposition of acid orange 7. For comparison, we use TiO₂ nanopowder (Degussa P25) compacted also on a Ti sheet. The present results demonstrate that the photocatalytic activity of self-organized TiO₂ nanotube layers can significantly be increased by electrochemical bias.     

脉冲沉积制备Cu2O/TiO2纳米管异质结的可见光光催化性能

在用阳极氧化法制备有序排列TiO₂纳米管阵列薄膜的基础上,引入脉冲沉积工艺,成功实现了均匀、弥散分布的Cu₂O纳米颗粒修饰改性TiO₂纳米管阵列,形成Cu₂O/TiO₂ 纳米管异质结复合材料. 利用场发射扫描电镜（FESEM）、场发射透射电镜（FETEM）、X射线衍射（XRD）、X射线光电子能谱（XPS）和紫外-可见漫反射光谱（UV-Vis DRS）对样品进行表征,重点研究了Cu₂O/TiO₂ 纳米管异质结的光电化学特性和对甲基橙（MO）的可见光催化降解性能. 结果表明,Cu₂O纳米颗粒均匀附着在TiO₂纳米管阵列的管口和中部位置,所制备的Cu₂O/TiO₂ 纳米管异质结具有高效的可见光光催化性能;在浓度为0.01 mol·L^-1的CuSO₄溶液中制得的Cu₂O/TiO₂纳米管异质结表现出最好的电化学特性和光催化性能;另外,对Cu₂O纳米颗粒影响光催化活性的机理进行了讨论.