共查询到20条相似文献,搜索用时 0 毫秒
1.
Masato Takeuchi Shiro Sakai Masaya Matsuoka Masakazu Anpo 《Research on Chemical Intermediates》2009,35(8-9):973-983
TiO2 thin film photocatalysts which could induce photoreactions under visible light irradiation were successfully developed in a single process by applying an ion engineering technique, i.e., the radio frequency (RF) magnetron sputtering deposition method. The TiO2 thin films prepared at temperatures greater than 773 K showed the efficient absorption of visible light; on the other hand, the TiO2 thin films prepared at around 573 K were highly transparent. This clearly means that the optical properties of TiO2 thin films, which absorb not only UV but also visible light, can be controlled by the preparation temperatures of the RF magnetron sputtering deposition method. These visible light responsive TiO2 thin films were found to exhibit effective photocatalytic reactivity under visible light irradiation (λ > 450 nm) at 275 K for the reductive decomposition of NO into N2 and N2O. From various characterizations, the orderly aligned columnar TiO2 crystals could be observed only for the visible light responsive TiO2 thin films. This unique structural factor is expected to modify the electronic properties of a TiO2 semiconductor, enabling the efficient absorption of visible light. 相似文献
2.
Kikuchi H Kitano M Takeuchi M Matsuoka M Anpo M Kamat PV 《The journal of physical chemistry. B》2006,110(11):5537-5541
TiO(2) thin films prepared by a radio frequency magnetron sputtering (RF-MS) deposition method were found to show an enhanced photoelectrochemical response in the visible light region. By controlling the temperature and the gaseous medium during the deposition step, it was possible to control the properties of these films. The photoelectrochemical behavior of the sputtered TiO(2) thin films was compared with that of a commercial TiO(2) sample, and the sputtered films showed higher incident photon to the charge carrier generation efficiency (IPCE of 12.6% at 350 nm) as well as power conversion efficiency (0.33% at 1.84 mW/cm(2)) than the commercial TiO(2) sample. Femtosecond transient absorption spectroscopy experiments have revealed that a major fraction of photogenerated electrons and holes recombine within a few picoseconds, thus limiting photocurrent generation efficiency. The mechanistic insights obtained in the present study should aid in designing semiconductor nanostructures that will maximize the charge separation efficiency and extend the response of the large band gap semiconductor TiO(2) into visible light regions. 相似文献
3.
Yu Horiuchi Shinya Mine Madoka Moriyasu Masakazu Anpo Tae-Ho Kim Masaya Matsuoka 《Research on Chemical Intermediates》2017,43(9):5123-5136
This work spotlights the formation behavior of visible light-responsive tantalum oxynitride (TaON) thin film photocatalysts under high substrate temperature in radiofrequency reactive magnetron sputtering deposition. The results emanating from the optimization of the sputtering conditions demonstrated that sputtered N atoms with high kinetic energy generated by controlling target–substrate distances and total pressures in the sputtering chamber were necessary to grow TaON phase even under N2-rich atmosphere. Based on these findings, TaON thin film photocatalysts were successfully synthesized by single-step sputtering under a high substrate temperature of 1073 K before heat treatment. The optimal thickness of TaON thin film photocatalysts was extrapolated to be 450 nm by photoelectrochemical measurements under visible light irradiation (λ > 450 nm), in which distinct photocurrents corresponding to water oxidation were observed. Moreover, the photoelectrochemical activity was able to be improved by postsynthetic heat treatment in gaseous NH3 and loading with IrO2 nanocolloids as cocatalysts. This finding would be because the thin film photocatalyst after heat treatment in NH3 under appropriate conditions possessed better crystallinity and moderate donor density. The optimized TaON thin film photocatalysts with IrO2 nanocolloids also exhibited photocatalytic activity for H2 evolution from aqueous medium containing methanol as a sacrificial electron donor under visible light irradiation (λ > 450 nm). 相似文献
4.
Afshin Ebrahimi Masaaki Kitano Kazushi Iyatani Yu Horiuchi Masato Takeuchi Masaya Matsuoka Masakazu Anpo 《Research on Chemical Intermediates》2013,39(4):1593-1602
Visible light-responsive TiO2 (Vis-TiO2) thin films were successfully developed by applying a radio-frequency magnetron sputtering deposition method by controlling various sputtering parameters such as the substrate temperature, Ar gas pressure, and the target-to-substrate distance. UV–Vis, XRD and SEM investigations revealed that optical property, the crystal structure, and photocatalytic activity of Vis-TiO2 are strongly affected by the sputtering parameters during the deposition step. Vis-TiO2 was found to act as an efficient photocatalyst for the H2 and O2 evolution from water under visible light irradiation (λ ≥ 420 nm). SIMS investigations have revealed that a slight decrease in the O/Ti ratio of the TiO2 thin films plays an important role in the modification of the electronic properties of Vis-TiO2 thin films, enabling them to absorb visible light. 相似文献
5.
Masaya Matsuoka Afshin Ebrahimi Masaki Nakagawa Tae-Ho Kim Masaaki Kitano Masato Takeuchi Masakazu Anpo 《Research on Chemical Intermediates》2009,35(8-9):997-1004
Visible light-responsive TiO2 thin film photocatalysts (Vis-TiO2) have been prepared on Ti metal foil (Vis-TiO2/Ti) or ITO glass (Vis-TiO2/ITO) substrates by a radio-frequency magnetron sputtering (RF-MS) method. The UV–Vis spectra as well as photoelectrochemical performance of Vis-TiO2 were affected by various calcination treatments such as calcination in air or NH3. Calcination treatment in NH3 (1.0 × 104 Pa, 673 K) was particularly effective in increasing the visible light absorption of Vis-TiO2 as well as in enhancing its photoelectrochemical performance and photocatalytic activity. A novel Vis-TiO2 thin film photocatalyst (Vis-TiO2/Ti/Pt) was prepared by an RF-MS method where Vis-TiO2 was deposited on one side of a Ti metal foil substrate and nanoparticles of Pt were deposited on the other side. The separate evolution of H2 and O2 from H2O could be successfully achieved by using an H-type glass cell consisting of two aqueous phases separated by Vis-TiO2/Ti/Pt and a proton-exchange membrane. It was found that the rate of the separate evolution of H2 and O2 was also dramatically enhanced by calcination treatment of Vis-TiO2 in NH3. 相似文献
6.
Nanocrystalline N-doped TiO2 powders were successfully prepared by hydrothermal reaction for 2 h at low temperature (120 °C) and at an applied pressure of 3 MPa. The grain size of the powders (calculated by use of Scherrer’s method) ranged from 8.2 to 10.2 nm. The BET specific surface area ranged from 151.0 to 220.0 m2/g. A significant shift of the light absorption edge toward the visible light zone was observed in the UV–visible spectra. XPS results showed that nitrogen atoms were incorporated into the TiO2 lattice. The photocatalytic activity of the synthesized N-doped TiO2 powders was evaluated by measurement of photodegradation of methylene blue (MB) in aqueous solution under visible light irradiation. The amount of MB degraded increased with increasing illumination intensity. 相似文献
7.
Masaaki Kitano Kazuhiro Iyatani Ebrahimi Afsin Yu Horiuchi Masato Takeuchi So-Hye Cho Masaya Matsuoka Masakazu Anpo 《Research on Chemical Intermediates》2012,38(6):1249-1259
Visible light-responsive TiO2 (Vis-TiO2) thin films able to absorb UV and visible light in wavelength regions of 250–600 nm were successfully developed by applying
a radio-frequency magnetron sputtering deposition method. These Vis-TiO2 thin films exhibited high activity for the photocatalytic oxidation of 2-propanol diluted in water even under visible light
irradiation (λ ≥ 450 nm). The photocatalytic activity of Vis-TiO2 thin films was dramatically enhanced by the deposition of Pt particles on the surface. Secondary ion mass spectrometry measurements
revealed that Pt particles are distributed from the top surface to the deep bulk of Vis-TiO2 thin films with a columnar structure. The unique columnar structure of Vis-TiO2 thin films plays an important role in the high photocatalytic performance. 相似文献
8.
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. 相似文献
9.
Masakazu Anpo Yuichi Ichihashi Masato Takeuchi Hiromi Yamashita 《Research on Chemical Intermediates》1998,24(2):143-149
The metal ion-implantation of titanium oxide with various transition metal ions was carried out by applying by high voltage
acceleration. The subsequent calcination of the implanted TiO2 in oxygen at around 723 K resulted in a large shift in the absorption spectra of the TiO2 toward visible light regions, its extent being dependent on the amount and the kind of metal ions implanted. Such metal ion-implanted
titanium oxide catalysts were active in carrying out various photocatalytic reactions such as the decomposition of NO into
N2, O2 and N2O at 275 K under irradiation with visible light longer than 450 nm. The application of this advanced, high energy metal ion-implantation
method enables the novel design of titanium oxide photocatalysts which can absorb and initiate vital reactions under visible
light and will contribute to the development of catalytic systems utilizing solar energy. 相似文献
10.
《化学研究》2016,(3)
以明胶为原料用水热法一步合成了碳量子点(CQDs),经过聚乙二醇表面修饰后,在乙醇溶液中与二氧化钛纳米片(TNS)复合形成了碳量子点高分散负载的CQDs/TNS复合光催化剂.对复合光催化剂进行了XRD、FT-IR、HRTEM和XPS表征,结果表明合成的碳量子点的平均粒径为4nm且具有较好的荧光性能.与纯TNS相比,CQDs/TNS复合光催化剂在可见光下对罗丹明B表现出很好的光催化降解活性.当CQDs/TNS复合光催化剂中CQDs含量为7.5%时光催化活性最好,并且在3次循环降解后活性仍保持不变.其优异的光催化活性来自于碳量子点的独特上转换荧光性能和二氧化钛纳米片高活性{001}晶面的共同作用. 相似文献
11.
Zhou J Takeuchi M Ray AK Anpo M Zhao XS 《Journal of colloid and interface science》2007,311(2):497-501
An ion-implantation method was used to prepare V-ion-implanted P25 TiO2 photocatalysts. Their photocatalytic activity for the degradation of formic acid under visible light irradiation (lambda>450 nm) was investigated. Upon implantation of V ions into the lattice of P25 TiO2, the photoactivity was remarkably enhanced. HRTEM images showed that the implanted V ions existed in the form of VO2(T) in the lattice of P25 TiO2. The intensity of photoluminescence (PL) spectra of V-ion-implanted P25 TiO2 decreased with the increase of the amount of implanted V ions, indicating the decrease of electron-hole pair recombination. It was also observed that the lower the PL intensity of V-ion-implanted P25 TiO2, the higher the photoactivity. 相似文献
12.
以TiH2为Ti源,H2O2为氧化剂,首先通过表面氧化得到不同状态的前驱体凝胶,然后采用后续水热处理制备Ti3+自掺杂的纳米Ti O2.考察了前驱体凝胶状态及水热处理时间对材料结构和性能的影响.利用X射线衍射、透射电子显微镜、X射线光电子能谱、电子顺磁共振波谱和紫外-可见漫反射光谱手段对样品进行表征.以次甲基蓝溶液为模拟废水评价样品的可见光催化降解性能.结果表明,与纯Ti O2相比,Ti3+的自掺杂使材料在可见光区有明显的吸收,并具有良好的可见光催化降解性能和循环使用性能.当采用黄色凝胶为前驱体时,在160°C下水热处理24 h所得样品在可见光下光催化降解次甲基蓝的反应速率常数(0.0439 min-1)是纯Ti O2的18.3倍. 相似文献
13.
Xie Jian Imanishi Nobuyuki Hirano Atsushi Takeda Yashuo Yamamoto Osamu Zhao Xin-Bing Cao Gao-Shao 《Journal of Solid State Electrochemistry》2011,15(9):2031-2039
Ag and Ag2O thin films have been prepared by radio frequency magnetron sputtering on Cu substrates and have been characterized by X-ray
diffraction, scanning electron microscope and atomic force microscope. The electrochemical performance of the thin films has
been studied by galvanostatic cycling and cyclic voltammetry. The potential dependence of Li-ion chemical diffusion coefficients,
[(D)\tilde]\textLi {\widetilde{D}_{\text{Li}}} , of the films has been determined by galvanostatic intermittent titration technique and electrochemical impedance spectroscopy.
It is found that Li-ion chemical diffusion coefficients of the Ag film range from 10−16 to 3 × 10−14 cm2 s−1. The Ag/Li2O composite that is formed from Ag2O after the first cycle exhibits higher
[(D)\tilde]\textLi {\widetilde{D}_{\text{Li}}} values than the Ag film, especially at a low Li-intercalation content. The phase transitions in the two-phase region cause
a significant decrease of chemical diffusion coefficients. 相似文献
14.
利用Sol-gel法制备了TiO_2纳米颗粒,然后以无水三氯化铁为氧化剂,室温固相氧化聚合噻吩,得到聚噻吩(Polythiophene,PTh)敏化纳米TiO_2形成的PTh/TiO_2复合纳米粉.以XRD、TEM、DRS等方法对其相组成、形貌及其光谱特性进行了研究.结果表明,所得纳米TiO_2为纯锐钛矿晶型,平均颗粒尺寸为18 nm;PTh/TiO_2复合物具有20× 80 nm的棒状形貌;DRS中吸收限在605nm处.以甲基橙作为模型试验了产品的光催化性能,结果表明,在太阳光照射下,120 min时PTh/TiO_2对甲基橙降解率达85.6%,光催化性能优于纯TiO_2、PTh及商品Degussa P25 TiO_2光催化剂.探讨了PTh促进TiO_2光催化性能的机理. 相似文献
15.
Zhang H Ming H Lian S Huang H Li H Zhang L Liu Y Kang Z Lee ST 《Dalton transactions (Cambridge, England : 2003)》2011,40(41):10822-10825
In this study, we report the facile fabrication of Fe(2)O(3)/CQDs nanocomposites, and investigate their effective photocatalytic activity for the photodegradation of toxic gas (gas-phase benzene and methanol) under visible light. The crucial roles of CQDs in the enhancement of photocatalytic activity of the Fe(2)O(3)/CQDs composites are illustrated. 相似文献
16.
Semiconducting silver iodate (AgIO(3)) was used to modify the visible light response of an AgI/TiO(2) (AIT) catalyst by a facile method. The uncalcined AIT (AITun) and AIT calcined at 200°C (AIT200) consisted of AgIO(3), AgI, and TiO(2) semiconductors, while that calcined at 450 °C (AIT450) was composed of AgI and TiO(2). The activity in p-chlorophenol (PCP) degradation under visible light irradiation using either AITun or AIT200 was much higher than that with AIT450, which was mainly attributed to the fact that the presence of AgIO(3) provided a new matching band potential. AIT200 exhibited better photocatalytic properties than AITun due to its higher crystallinity after calcination. Moreover, the high catalytic activity of AIT200 was maintained after five successive cyclic experiments under visible irradiation. Considering the effect of radical scavengers and N(2) purging on the photocatalysis process, we deduced that the probable pathway of PCP degradation was mainly a surface charge process, caused by valence band holes. 相似文献
17.
本文以超声波为晶化方法在低温下制得了炭纤维负载的Ti O2光催化剂(Ti O2/ACF)。通过X衍射、扫描电镜、液氮吸附等对晶化中所得催化剂Ti O2的晶型、形貌和织构进行了考察,并以甲基橙为降解物考察了催化剂活性。结果表明:在超声波作用下,Ti O2前驱体先被均匀负载到炭纤维表面,然后被晶化为14.2 nm的锐钛矿粒子;所得催化剂晶粒在炭纤维表面形成了1.1nm左右的微孔,其介孔体积比炭纤维高;超声晶化时间对晶粒大小无明显影响,但对催化剂活性有重要活性影响:60分钟的晶化活性最好,过长时间会使负载的Ti O2脱落,降低催化剂活性。实验结果还表明,Ti O2/ACF催化剂在重复使用中活性基本稳定,且对甲基橙吸附比原炭纤维高,其原因在于催化剂介孔体积的增加。 相似文献
18.
A novel chlorine-doped titanium dioxide catalyst with visible light response was prepared by hydrolysis of tetrabutyl titanate
in hydrochloric acid. The catalyst samples were characterized by X-ray diffraction (XRD), transmission electron microscopy
(TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Results
showed that the doped element of Cl lowered the temperatures of phase transformation of TiO2 from amorphous to anatase and from anatase to rutile. The absorption edge of chlorine-doped TiO2 calcined at 300°C shifted to visible light region. X-ray photoelectron spectroscopy results proved that chlorine existed
in the TiO2 crystal lattice as anion. The photocatalytic degradation of phenol showed that under visible light (λ > 400 nm) irradiation, the chlorine-doped TiO2 calcined at 300°C displayed the best performance, the degradation ratio of phenol was 42.5% after 120 min.
Translated from Chinese Journal of Catalysis, 2006, 27(10): 890–894 [译自: 催化学报] 相似文献
19.
《化学研究》2015,(6)
通过沉积法将光活性AgBr半导体负载到介孔TiO_2-SiO_2载体上合成了新型的AgBr/TiO_2-SiO_2复合光催化剂.采用X射线衍射仪、高分辨透射电镜、紫外-可见吸收光谱仪等分析了AgBr/TiO_2-SiO_2复合光催化剂的结构和光谱性质;并采用BET法测定了样品的比表面积和孔分布.结果表明,介孔TiO_2-SiO_2载体的比表面积为135.5m2/g,平均孔径约为3.8nm,AgBr的负载可以有效地将AgBr/TiO_2-SiO_2复合光催化剂的吸收光谱从紫外光区扩展到可见光区,且AgBr和TiO_2形成了异质结结构,强化了AgBr与介孔TiO_2-SiO_2载体的协同作用.以罗丹明B作为探针分子,评价了AgBr负载量对复合光催化剂可见光催化活性的影响.结果发现,当AgBr∶TiO_2=0.1,0.2,0.3和0.4(物质的量之比,下同)时,复合光催化剂的光催化反应速率常数分别为0.008 5、0.028 6、0.024 6和0.019 3min-1,活性先增加后减小,当AgBr∶TiO_2=0.2时,复合光催化剂表现出最高的光催化活性,并且在5次循环测试中均表现出较高的光催化活性. 相似文献
20.
The preparation of amorphous TiO2 film coupled with various metal-oxide semiconductors and their photocatalytic activities evaluated by photo-degradation of methylene blue and rhodamine B aqueous solution are briefly reviewed. The proposed photoreaction mechanism of the amorphous composite semiconductor and the differences between amorphous TiO2-based films and crystalline TiO2 photocatalytic materials in terms of preparation and usage are addressed. The inactive intrinsic amorphous TiO2 film coupled with various metal oxides were found to gain high photocatalytic activity. These dopants induce forming new energy levels in the band gap of TiO2 to enhance the charge separation of the photoinduced electrons and holes and extend the light absorption of TiO2-based photocatalytic films into the visible region. In addition, two different effects of coupling metal oxides have been proved: the introduction of oxides of W, Cr, V, Ag, and Mo can significantly increase the photo-reactivity of amorphous TiO2 film, while the combination of oxides of Zr, Sn, Sb, Cu, Ta, Fe, and Ni cannot affect the inactivity of pure amorphous TiO2 film. 相似文献