Anatase Research Articles

Photo-oxidation of ethylene over mesoporous Tio2/Sio2 catalysts

Mesoporous TiO2/SiO2 catalysts were prepared in order to increase the post-harvest life of climacteric fruits and vegetables reducing ethylene concentration by photo-oxidation. TiO2/SiO2 powders were synthesized by sol-gel method using titanium isopropoxide Ti(OiPr)4 and tetraethoxysilane Si(OC2H5)4 as source of metal oxides. Mesoporous SiO2 framework was used as catalyst support of nanostructured TiO2 to enhance the photocatalytic efficiency. Different TiO2/SiO2 molar ratios were prepared through sol-gel process. A liquid-crystal template route allowed to obtain the mesoporous silica structure, and contemporary TiO2 insertion in the silica framework. The X-ray diffraction (XRD) analysis demonstrated that silica insertion in TiO2 framework inhibits the anatase to rutile phase transformation at higher sintering temperature. The photocatalytic efficiency of the catalysts was measured by the photo-oxidation of ethylene gas under UV light irradiation. Complete photo-oxidation of ethylene was observed after 24 h of reaction time. Results show that the silica framework increases the surface area of the composites and make crystalline anatase phase more stable at higher temperature.

Carbon dioxide reduction with hydrogen in a continuous catalytic monolith photoreactor

Photocatalytic CO2 reduction with H2 as a reductant over gold (Au)-doped TiO2 nanocatalysts in a continuous monolith photoreactor has been investigated. The nanocatalysts were characterized by XRD, SEM, N2 adsorption-desorption and UV-Visible spectroscopy. Crystalline nanoparticles of anatase phase TiO2 were obtained in the Au-doped TiO2 samples. CO was the major product over 0.5 wt. % Au-doped TiO2 with the yield rate of 12,305 ppm g-catal.-1 h-1 , 318 times higher than un-doped TiO2 catalyst. Significantly higher photoactivity of Au-doped TiO2 was obviously due to fast electron transfer with hindered recombination rates and larger illuminated surface area inside the monolith channels. The CO production rate was gradually reduced with increasing the space velocity. The stability of the reused catalysts for CO production sustained at cyclic runs. It is evident Au-doped TiO2 nanocatalyst supported over monolith channels is highly potential for continuous CO2 photoreduction to CO and hydrocarbons.

煅烧温度对N掺杂TiO 2 中空介孔微球光催化性能的影响

以三乙胺为氮源,采用层层自组装和高温煅烧方法制备球形形貌良好的N掺杂TiO2中空介孔微球(N-THS),使用XPS、XRD、UV-VisDRS等手段研究了煅烧温度对其结构和光催化性能的影响。结果表明,N进入TiO2晶格内取代了部分O元素并改变了晶格中Ti和O的化学状态;在400-600℃煅烧所得TiO2呈现锐钛矿相结构,将煅烧温度提高到700℃则出现向金红石相的转变,且TiO2的晶粒尺寸随着煅烧温度的提高而增大。N-THS在可见光区具有明显的吸收性能,吸收光谱带也发生了明显红移,对MO溶液均具有较好的降解效率;而随着煅烧温度的降低,可见光区吸收相应增强,降解效率提高,在400℃锻烧的N-THS经光照射80min后其降解率达到93.5%。

Hydrothermal Growth and Photoelectrochemistry of Highly Oriented, Crystalline Anatase TiO2 Nanorods on Transparent Conducting Electrodes

Oriented, Crystalline Anatase TiO2 Nanorods on Transparent Conducting Electrodes Dong-Dong Qin,† Ying-Pu Bi,‡ Xin-Jian Feng, Wei Wang, Greg D. Barber, Ting Wang,† Yu-Min Song,† Xiao-Quan Lu,† and Thomas E. Mallouk* †Key Lab of Bioelectrochemistry and Environmental Analysis of Gansu, College of Chemistry and Chemical Engineering, The Northwest Normal University, Lanzhou, Gansu 730070, People’s Republic of China Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States ‡National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Acadamy of Sciences, Lanzhou, Gansu 730000, People’s Republic of China Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Acadamy of Sciences, Suzhou, Jiangsu 215123, People’s Republic of China

The photocatalytic removal of azo dye by nickel-doped titanium dioxide nanoparticles coated on Iranian natural zeolite clinoptilolite fixed substrate

Aims: The purpose of this study was to remove azonium compound using the photocatalytic property of nickel (Ni)-doped titanium dioxide (TiO 2 ) nanoparticles coated on Iranian natural zeolite. Materials and Methods: Nickel-doped TiO 2 nanoparticles with the molar ratios of 0, 0.17, 2, 9% Ni/TiO 2 were prepared via the sol-gel process and coated on Iranian natural zeolite clinoptilolite (CLI). Afterward, X-ray diffraction, scanning electron microscopy and inductively coupled plasma studies were conducted to describe Ni and titanium. Photocatalytic removal of azo dye in concentrations of 25 and 50 mg/L was performed by fixing the composite under ultraviolet irradiation. Results: TiO 2 nanoparticles in both the anatase and rutile phases were obtained via the sol-gel method with the ratios of 86.33%, (34.44 nm particle size) and 13.67% (18 nm particle size) and were then coated on Iranian natural CLI zeolite. The results indicated that the photocatalytic removal efficiency of the 9% Ni/TiO 2 -CLI samples, in which the azo dye concentrations were 25 and 50 mg/L, was 93% and 79% at 160 min. In addition, the composition of the 9% Ni/TiO 2 -CLI possessed the greatest removal rate difference of azo dye at the concentrations of 25 and 50 mg/L. Conclusion: Application of Iranian CLI as a substrate is the most cost-effective way to increase the photocatalytic activity. Furthermore, adding Ni to TiO 2 can increase the photocatalyst removal efficiency of azonium compound.

Genotoxic effects of oral-exposed TiO2 nanoparticles on bone marrow cells in young rats

To explore the genotoxic effects of oral-exposed TiO2 nanoparticles on bone marrow cells in young rats. Twenty-eight SD male young rats (4 weeks old) were randomly divided into 4 groups, which were exposed to TiO2 nanoparticles ((75 ± 15) nm, anatase) through intragastric administration at 0, 10, 50 and 200 mg/kg body weight (bw) every day for 30 days. The bone marrow cells were collected for micronuclei and γ-H2AX immunofluorescence analysis. The percentage of γ-H2AX foci-positive cells (37.4 ± 10.0)% in the 50 mg/kg bw dose group were significantly higher than that in the control group (19.8 ± 3.1)% (t value was -17.59, P < 0.01). No significantly difference was found in polychromatic erythrocyte/normochromatic erythrocyte (PCE/NCE) ratio and PCE micronucleus rate between three experimental groups and control group. TiO2 nanoparticles can increase the frequency of DNA double-strand breaks in bone marrow cells, but has no effect on micronucleus of bone marrow cells in young rats.

TRANSISI FASA TITATNIUM OKSIDA MELALUI KONDENSASI EX-SITU HIDROGEN TITANAT TIPE STRUKTUR LEPIDOKSROSIT

The objectives of the research are to study of the structure type of titanium dioxide (TiO 2 ) obtained form the ex-situ condensation of hydrated hydrogen titanates with the structure type of lepidocrocite. Hydrated hydrogen titanates were obtained by ion exchabge of H + for Cs + in cesium titanates by 1 M HCl solution by Chimie Douce method. The results show that TiO 2 (B), anatase, and anatase-rutile mixture were obtained heat treatment of hydrated hydrogen titanate at 100, 200, 300, 500, and 600 o c respectively. The powders were characterized by X-rays diffractometer (XRD), High Resolution Scanning Electron Microscopy (HRSEM) and High Resolution Transmission Electron Microscopy (HRTEM). The research indicated that the protonic titanate, H 0.54 Ti 1.865 0.135 O 4 0.5H 2 O ( =vacancy), lost the interlayer water by being heated up to 200 o C to produce a dehydrated phase, H 0.54 Ti 1.865 0.135 O 4 . Above 300 o C, the dehydrated phase completely transformed to TiO 2 (B) and anatase was obtained as pure phase at 600 o C. The phase transformed as the following process: H 0.54 Ti 1.865 0.135 O 4 0.5H 2 O a H 0.54 Ti 1.865 0.135 O 4 0.25H 2 Oa H 0.54 Ti 1.865 0.135 O 4 a TiO 2 (B) a TiO 2 -anatase.

锐钛矿型TiO 2 纳米管的离子液体辅助水热合成及紫外光催化活性

在离子液体[Bmim]OH辅助的水热条件下合成了结晶度较好的偏钛酸纳米管，经470 ℃煅烧2 h，可转变为锐钛矿型TiO 2 纳米管. 对产物的物相、形貌和比表面积等进行了表征. 结果表明，锐钛矿型TiO 2 纳米管的比表面积约为355 m 2 /g，主孔径约为25 nm. 锐钛矿型TiO 2 纳米管和偏钛酸纳米管均呈现出明显的紫外光催化降解对氯苯酚的活性，锐钛矿型TiO 2 纳米管的降解效率约为44%（1 h）. 离子液体的加入不仅可扩大水热合成的温度范围，且有助于提高偏钛酸纳米管的结晶度.

Theoretical studies on adsorption of PFOS on anatase TiO2 surfaces

Adsorption behavior of perfluorooctane sulfonate(PFOS) on anatase TiO2 surfaces was studied with DFT-B3LYP method.Physisorption including hydrogen-bond interaction and chemi-adsorption including bidentate binuclear(BB) and monodentate mononuclear(MM) complexes were investigated in the study.Calculations of adsorption energy(Eads) and Gibbs free energy(ΔGads) showed that physisorption was easier to occur.Chemi-adsorption surface complexes were produced by reaction between PFOS and surface water(H2O) or hydroxyl(—OH),and the reaction to replace H2O was easier than that to replace —OH group.MM1(reacted with one H2O of surface) surface complex was the most thermodynamically favorable chemi-adsorption mode.The thermodynamically favorable and stability order of PFOS adsorbed on anatase TiO2 surfaces was H-bonded(hydrogen bonded adsorption)MM1(reacted with one H2O of surface)BB1(reacted with two H2O of surface)MM2(reacted with one —OH of surface)BB2(reacted with one H2O and one —OH of surface).Results of bond length analysis indicated that the interaction between H2O/—OH function group on TiO2 surface and sulfonate group in PFOS resulted in the formation of moderate intensity hydrogen bond.Charges transferred from PFOS molecule to TiO2 surface during chemi-adsorption process,leading to the formation of Ti—O—S bond,and transfered electrons in the process were mainly from strong electronegative atoms O and F.

NANO CORE-SHELL PHOTOCATALYSTS FOR TREATMENT OF WATER POLLUTANTS

Nano-materials are considered as a part of nanotechnology which is expected to provide many applications in the future. However, separation and reuse of the nano materials are challenging for catalysis application in liquid phase reactions. In this research, nano core-shell containing TiO2 which possess magnetic property have been synthesized using two methods: sol-gel method and modified sol-gel method. The materials have been characterized using different techniques such as X-ray Diffraction (XRD), Transmission electron microscopy (TEM). TiO2 anatase structure of the catalysts have been verified from XRD patterns. The potential application for the treatment of water contaminated by organic pollutants has been investigated via the photocatalytic degradation of methyl orange (MO) and p-nitrophenol (NP) as models using the as-synthesized materials. The magnetic photocatalyst which was synthesized by the sol-gel method, exhibited comparable activity as the commercial TiO2 (P25) after three hours reaction. However, the catalyst prepared by the modified sol-gel method performed high recyclability.

Polymetallic mineralization of the Boranja orefield, Podrinje Metallogenic District, Serbia: zonality, mineral associations and genetic features

In the Serbo-Macedonian Metallogenetic Province, which is a part of the Alpine metallogenic unit, the ore deposits lie in number geotectonic units; they embrace part of the Vardar Zone, Serbo-Macedonian massif, and a small part of the Dinarides. This metallogenic province has been delineated mostly by reference to the Neogene metallogeny, related predominantly to granodiorite magma. These deposits include the most significant Pb-Zn and Sb deposits in Serbia, as well as smaller Bi, Mo, Cu, Fe, Sn, Au and minor U, W and Hg deposits. The Podrinje Metallogenic District belongs to the Serbo-Macedonian Metallogenetic Province. Smaller metallogenic provinces are isolated within the scope of the following orefields: Cer (Northwest Serbia), Boranja (West Serbia), and Srebrenica (East Bosnia & Herzegovina). Polymetallic deposits in the Boranja orefield are genetically related to the emplacement of a Tertiary granodiorite complex. It consists primarily of a large number of sulfide deposits with Pb-Zn, and Sb; with subordinate Cu, As, Bi and Ag. Among them, the presence of small magnetite deposits, connected to the pyrometasomatic (skarn) stage is significant. Skarns are of calcic type, and were formed along contacts of Triassic limestones and quartz diorites. Ore minerals are similar among the various types of orebodies in the Boranja orefield and consist of sulfides (pyrrhotite, pyrite, marcasite, chalcopyrrhotite, chalcopyrite, cubanite, mackinawite, valleriite, covelline, chalcocite, bismuthinite, molybdenite, sphalerite, mercurian sphalerite, greenockite, galena, arsenopyrite, stibnite, duranusite, realgar, orpiment, cinnabar, metacinnabar); sulfosalts (bursaite, cannizzarite, cosalite, aikinite, ustarasite, tetradymite, ferrian tetrahedrite, argentian tetrahedrite, pyrargyrite, diaphorite, freieslebenite, schirmerite, fizelyite, stannite, jamesonite, boulangerite, bournonite, As-bournonite, falkmanite, zinkenite, fuloppite, robinsonite, plagionite, twinnite, geocronite, gratonite); telluride (calaverite); native metals and alloys (gold, silver, electrum, bismuth, arsenic); oxides and complex-oxides (magnetite, hematite, rutile, anatase, scheelite, powellite, valentinite, senarmontite, kermesite, adamite, arsenolite); and gangue minerals (silicates, carbonates, fluorite, calcite, siderite, Mn-Zn siderite, fluorite, apatite, barite, dolomite, anglesite, cerussite, smithsonite, otavite, malachite, azurite, scorodite, quartz, limonite, organic matter). Minerals of the titled orefield were formed in several successive stages, which together correspond to a unique cycle of mineralization that is genetically related to the subvulcanic-plutonic intrusion of the Neogene-aged magmatic Boranja complex. Mineral associations, which have spatial-zonal arrangement, are rhythmically developed from the Tertiary granodiorite of Boranja to outside surroundings: A) Fe-Cu(Bi) belt → B) Pb(Ag)-Zn belt → C) Sb(As) belt → D) CaF 2 (Pb-Zn) belt.

졸-겔법을 이용한 TiO2박막의 광촉매 특성

$TiO_2$ 박막을 저온 열처리 졸-겔 법으로 합성하였다. 박막의 기판은 면적이 $100mm^2$ 인 붕규산염 유리를 사용하여 시료를 $300^{\circ}C$ 부터 $1100^{\circ}C$ 까지 열처리하였고, 이때 제조된 박막의 두께는 약 $1.5{\mu}m$ 정도였다. $300^{\circ}C$ 에서 2시간 동안 열처리한 $TiO_2$ 박막은 아나타제 상을 나타내었고 열처리 온도가 증가함에 따라 비정질 상태에서 아나타제상과 루타일 상이 공존하면서 각 상의 분율이 변화하였다. SEM 분석에 의하면 박막의 입자 크기는 $0.1{\sim}0.54{\mu}m$ 이었으며 Uv-visible 반사특성에 있어서 390nm부근에서 광흡수가 되는 것을 알 수 있었다. 따라서 낮은 열처리 온도에서 생성된 $TiO_2$ 박막은 주로 아나타제 상을 가지며 광촉매 특성을 2.4배 증가시키는 것으로 나타났다. 【Thin film of $TiO_2$ was obtained by the sol-gel dip method on the brosilicate glass substrate. It was found that the film was about $1.5{\mu}m$ thick as obtained by 4 successive coatings and annealed at varied temperatures ranged from $300^{\circ}C$ to $1100^{\circ}C$ for 2 hrs. The substrate used was having the surface area of $100mm^2$ . Increasing the annealing temperature caused to change in mineralogical phase of titanium oxide i.e., amorphous, crystalline antase to rutile phases. The particle size of the titanium oxide film were ranged from $0.1{\sim}0.54{\mu}m$ estimated by the SEM analysis. The material showed an absorbance maximum at the wavelength 390nm obtained by UV-visible spectrophotometer. These results therefore, indicated that the $TiO_2$ film obtained relatively at low annealing temperature consisted predominantly with anatase phase; possessed higher photocatalytic behavior i.e., 2.4 times higher than that of only UV lamp irradiation.】

Effects of La/S co-doping on the electronic structures of anatase TiO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;

采用基于密度泛函理论的第一性原理对La/S共掺杂前后锐钛矿相TiO 2 的晶格参数、 电荷布居以及电子结构进行了计算. 结果表明: La/S共掺杂导致TiO 2 晶格膨胀并减小了锐钛矿相TiO 2 的禁带宽度, 同时在TiO 2 禁带之内引入了局域态的杂质能级, 这些杂质能级可以充当电子从价带到导带跃迁的“桥梁”以减小激发光子的能量从而提高太阳光的利用率. 为实验上合成的La/S共掺杂TiO 2 可见光催化剂提供了一定的理论基础.

First-Principles Calculation of Bi-Doped Anatase TiO2

The electronic structures and optical properties of pure anatase TiO2 and Bi-doped anatase TiO2 were calculated using the plane-wave ultra-soft pseudo-potential (PWPP) method based on the density functional theory (DFT). The results indicate the populations of Ti atoms decline and those of O atoms increase. The Bi doping introduces impurity energy level into the forbidden band. It was found that the impurity energy level is composed of Bi6s, O2p and Ti3d orbitals. The forbidden band width of the Bi-doped anatase TiO2 increases a little. But the detrimental effect arose from the enlargement of forbidden band is offset by the function of the impurity energy level, which results in a red shift of the absorption edge and a strong absorption ability for the Bi-doped anatase TiO2.

Phonon Confinement Model to Measure the Average Sizes of Anatase Nanoparticles Synthesized by a Solvothermal Method Using H2O2

Universidade Federal do Piaui Centro de Ciencias da Natureza Departamento de Quimica Departamento de Fisica LIMAV

Effect of titanium dioxide nanoparticles on hemogram in rats with gastric ulcer

To explore the effect of titanium dioxide (TiO₂) nanoparticles on hemogram in rats with gastric ulcer. Physicochemical properties of TiO₂ nanoparticles were characterized. Twenty-four clear class SD male rats, aging 8 week-old, were randomly divided into 4 groups, 6 rats for each group. 20% acetic acid were injected into the rats' stomach on the border of gastric body and pyloric antrum, and hereby established the gastric ulcer model. The rats in 4 groups were exposed to TiO₂ nanoparticles through intragastric administration at 0, 10, 50 and 200 mg/kg body weight respectively for 30 days. Afterwards, the rats were conducted blood routine test and blood coagulation test for analysis. TiO₂ nanoparticles were anatase crystals, closely spherical shape, whose average grain diameter was (75 ± 15) nm. The levels of white blood cell (WBC) count ((8.48 ± 3.28)×10⁹/L), lymphocyte (LYM) ((6.85 ± 2.53)×10⁹/L), monocyte (MOD) ((0.27 ± 0.12)×10⁹/L), granulocyte (GRN) ((1.37 ± 0.86)×10⁹/L), red blood cell (RBC) ((8.20 ± 0.49)×10⁹/L) and hematocrit (HCT) ((45.3 ± 1.4)%) in the 200 mg/kg dose group were significantly higher than those in the control group ((2.63 ± 0.34)×10⁹/L, (2.25 ± 0.26)×10⁹/L, (0.05 ± 0.06)×10⁹/L, (0.33 ± 0.26)× 10⁹/L, (4.87 ± 2.37)×10⁹/L and (27.2 ± 13.3)%, respectively; t values were -3.449, -3.825, -3.554, -3.097, -2.972 and -2.936 respectively, P values all < 0.05). The levels of WBC ((6.88 ± 3.06)×10⁹/L), MOD ((0.20 ± 0.07)×10⁹/L), RBC ((7.79 ± 0.48)×10⁹/L) and HCT ((42.7 ± 2.8)%) in 50 mg/kg dose group were also statistically higher than those in the control group (t values were -2.507, -2.367, -2.605 and -2.511 respectively, all P values < 0.05). There was no statistically difference found in other blood routine index and coagulation index between the three experimental groups and control group. The long term intake of TiO₂ nanoparticles caused a statistically increase in the amount of WBC and RBC in rats with gastric ulcer; however, there was no obvious changes found in blood platelet and coagulation index.

Growth, differentiation, and migration of osteoblasts on transparent Ni doped TiO2 thin films deposited on borosilicate glass

A simple and cost effective dip coating method was used to deposit thin films of amorphous (AM) or anatase (AN) titanium dioxide (TiO(2)) on borosilicate glass substrates, either with or without prior doping of TiO(2) with nickel (Ni) cations by a specially designed sol gel technique. The objective of the study was to compare the physicochemical and biological properties of these films and assess their use in orthopedic implants or for in vitro cell biological studies. Analytical techniques such as XRD and XPS, in combination with ATR-FTIR and SEM revealed that only AN films, prepared by controlled heating up to 450°C, irrespective of prior doping with Ni, contained significant crystalline structures of variable morphologies. This observation could be linked to the carbon and oxygen contents and the availability of functional groups in the films. Cell biological studies revealed that Ni doping of TiO(2) in both AM and AN films improved the adhesion, spreading, proliferation, differentiation, and migration of MC3T3 cells. Our studies provide a new approach to prepare optically transparent metal surfaces, with tunable physicochemical properties, which could be suitable for eliciting optimal osteoinductive cell responses and permit the detailed in vitro cell biological studies of osteoblasts.

Effects of Fe-Doping on the Structures and Photocatalytic Activities of TiO2 Thin Films

The Fe-doped TiO2 films were prepared by sol-gel method and characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),confocal microscope Raman spectrometer(Raman),UV-Vis absorption spectroscopy(UV-Vis) and atomic force microscopy(AFM).The photocatalytic activities of the films were evaluated by using the degradation of the methyl orange.The results showed that TiO2 in Fe/TiO2 films took an anatase structure when calcinated between 300 ℃ and 600 ℃.Increasing the calcination temperature up to 700 ℃,TiO2 transformed to rutile phase.The roughness and the grain size of Fe/TiO2 films grew gradually with the increases of the doping amount of Fe content and the calcination temperature.The photon excited wavelength of the Fe/TiO2 films moved to the visible light gradually with the increase of number of coating layer.Low levels of Fe-doping improved the photocatalytic activities of the TiO2 thin films,while higher doping decreased the photocatalytic activities of TiO2 thin films.The optimal Fe-doping was found to be 0.1% for the maximum degradation of methyl orange.

Comment on “Generalized Gradient Approximation +U Study for Metallization Mechanism of Niobium-Doped Anatase Titanium Dioxide”

Comment on “Generalized Gradient Approximation +U Study for Metallization Mechanism of Niobium-Doped Anatase Titanium Dioxide”

Fabrication and Photoelectrocatalysis Performance of Expanded GraphiteSupported Anatase Nano Titanium Dioxide

Anatase TiO2 coatings on highly porous expanded graphite(EG) were prepared by equal volume impregnation method.The morphology of EG with and without TiO2 coatings were studied by scanning electron microscope.The XRD pattern of TiO2 power was also studied.The composite material was filled into the novel home-made photoelectric reactor to degrade textile waste water containing reactive blue.The effects of different degradation technologies,such as photocatalysis,electro-oxidation,and photoelectrocatalysis were investigated and compared.The results show that chemical oxygen demand(COD) removal and color removal efficiency of the waste water by photoelectrocatalysis using 0.1 mol/L NaCl as supporting electrolyte is 93.1% and 99.3%,respectively,which are much higher than those obtained by using only photocatalysis or electrocatalysis.