钛种植体表面二氧化钛涂层改性的研究进展

由于钛种植体良好的生物相容性以及载力能力,成为骨植入物中最适合的材料。然而,由于其表面天然形成的TiO2涂层的高度不稳定性及易被体液腐蚀等特点,导致种植体周围易诱发感染以及骨整合不足等问题。为此,学者们对钛种植体表面TiO2涂层的合成方法进行改进以增强涂层的稳定性,对种植体表面TiO2涂层进行抗菌纳米材料修饰以提高涂层的抗菌性能、骨整合以及软组织整合能力。

Preparation of TiO_2-activated carbon complex membranes and their photoelectrocatalytic activity

The experimental process of preparing TiO 2 activated carbon complex membranes with activated carbon powder as main carrier, PTFE as binder and wire netting as matrix is described in detail, and both photo catalysis and photo electro catalysis are measured to study the properties of complex membranes. Experimental results show that the photo catalytic activity of the membranes is high and stable in the process of treating Rhodamine B; the application of an electric field accelerates the speed of photo catalysis, and the efficiency of photo catalysis is increased 2.5 times when the applied voltage is 0.8 V; and the degradation of Rhodamine B follows the dynamics of first order reaction. It is concluded from the discussion of experimental results that the preparation process of TiO 2 activated carbon complex membranes is a simple low cost process suitable for large scale application.

Preparation of Photocatalytic TiO_2 and TiO_2-SiO_2 Particles and Application to Degradation of Trace Organics in Aqueous Solution

TiO2 and TiO2-SiO2 photocatalysts were prepared by sol-gel and supercritical CO2 fluid drying method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), etc. Their catalytic properties were tested through the photocatalytic degradation of phenol and aniline in wastewater. The results show that the developed fluidized photocatalytic reactor (FPR) and TiO2 catalyst had better performance in degrading pollutants as compared with slurry photocatalytic reactor (SPR) and commercial TiO2 catalyst. The composition and crystal form of TiO2-SiO2 composite oxide had obvious influence on catalytic effect and TiO2-SiO2 photocatalysts showed better catalytic activity and stability.

A Study on the Photoreduction of Green House CO2 Gas Catalyzed by TiO2 to Form Methane and Methanol

A photoreduction of CO2 gas catalyzed by TiO2 powder has been studied with purpose to form methane and/or methanol as well as to prevent global warming. The photoreduction was carried out in a batch horizontal column that is by irradiating a mixture of CO2 with water vapor in the presence of TiO2 powder for a period of time. Gasses produced were analyzed by gas chromatography method. In this study the effect of reaction time and TiO2 mass on the results has been evaluated. The research results indicate that from the photoreduction, some products have been obtained. The products are CH4, CH3OH, and C2H2 and C2H4. It is found that the reaction time and TiO2 mass control the types and the concentration of the products. The photoreduction carried out for 12 h results in CH4, C2H2 and C2H4 with low concentration, but when the reaction time was extended up to 24 h and 48 h, CH4 and CH3OH with higher concentration are produced. By using 25 g and 50 g of TiO2 photocatalyst in the photoreduction, only the CH4 is yielded, meanwhile a mixture of CH4 and CH3OH is formed when 100 g of TiO2 was applied. The production of CH4 and CH3OH by photoreduction of CO2 with water vapor in the presence of TiO2 photocatalyst has been successfully achieved. However, the improvement of the quantity of the targeted products is required.

Fabrication of nanoporous TiO_2 films with novel surface morphology on conducting glass(FTO) substrate

The crystalline structure and surface morphology of TiO2 semiconductor coating play an important role in the conversion efficiency of dye-sensitized solar cells. In order to obtain TiO2 coating with controllable morphology and high porosity, nanoporous TiO2 films were fabricated on conducting glass （FTO） substrates, Ti thin films （1.5-2 gin） were deposited on conducting glass （FTO） substrates via the DC sputtering method, and then electrochemically anodized in NH4F/ethylene glycol solution. The crystalline structure and surface morphology of the samples were characterized by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM）, respectively. The influences of anodizing potential, electrolyte composition, and pH value on the surface morphology of nanoporous TiO2 films were extensively studied. The growth mechanism of nanoporous TiO2 films was discussed by current density variations with anodizing time. The results demonstrate that nanoporous TiO2 films with high porosity and three-dimensional （3D） networks are observed at 30 V, when the NH4F concentration in ethylene glycol solution is 0.3% （mass fraction） and the electrolyte pH value is 5.0.

Synthesis of Three-Dimensional Agaric-like Biomorphic TiO_2 by a Facile Method with Coscinodiscus sp.Frustule

The paper aims to expand the application of natural marine algae. Marine diatoms, which have intricate frustule struc- tures, can serve as bio-template for preparing three-dimensional materials. A simple and effective approach to synthesize the corru- gated agaric-like biomorphic TiO2 templated with frustule of Coscinodiscus sp. is reported. In the sol-gel preparation process, the titania-coating on the frustule is prepared through the deposition and condensation with the aid of acetylacetone （acac） as a control- ling agent to make the precursor Ti（BuO）4 hydrolyze slowly. The as-prepared titania-coated frustule and biomorphic TiOz is charac- terized by scanning electron microscopy （SEM） attached with energy dispersive X-ray spectrometer （EMAX） and X-ray diffraction （XRD）. The microstructure of the corresponding titania nanoparticles appears to be sphere with the diameters distributed around 10-20nm. The templating process is repeated for three cycles. Subsequently, the three-dimensional freestanding corrugated aga- ric-like biomorphic TiO2 structure is obtained by a selective removal in the NaOH solution. As far as we known, the 3D freestanding corrugated agaric-like biomorphic TiOz with greatly increased surface area is obtained for the first time.

Formation of active radicals and mechanism of photocatalytic degradation of phenol process using eosin sensitized TiO_2 under visible light irradiation

The role of oxygen and the generation of active radicals in the photocatalitic degradation of phenol were investigated using the eosin sensitized TiO2 as photocatalyst under visible light irradiation. Diffuse reflectance spectra show that the absorbancy range of eosin/TiO2 is expanded from 378 nm (TiO2 ) to about 600 nm. The photocatalitic degradation of phenol is almost stopped when the eosin/TiO2 system is saturated with N2 , which indicates the significance of O2 . The addition of NaN 3 (a quencher of single oxygen) causes about a 62% decrease in the phenol degradation. The phenol degradation ratio is dropped from 92% to 75% when the isopropanol (a quencher of hydroxyl radical) is present in the system. The experimental results show that there are singlet oxygen and hydroxyl radical generated in the eosin/TiO2 system under visible light irradiation. The changes of absorbancy indicate that the hydrogen peroxide might be produced. Through the analysis and comparison, it is found that the singlet oxygen is the predominant active radical for the degradation of phenol.

Effect of Dispersity and Porous Structure of TiO2 Nanopowders on Photocatalytic Destruction of Azodyes in Aqueous Solutions

Photocatalytic activity of TiO2 nanopowders of anatase modification with various particle sizes and specific surface areas has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue and direct blue 2C azodyes. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that TiO2 nanopowders have the particles size of 5-120 nm with the specific surface area of 15-120 m2·g^-1. The used TiO2 samples are characterized by mesoporous structures with average pore size of 4.3-14.9 nm. The photocatalytic activity of TiO2 was evaluated via decolorization of azodyes solutions. It was shown that the efficiency of decolorization symbatically changes with the dye adsorption value on TiO2 surface and the degree of decolorization rises when the surface area of TiO2 nanopowders increases. It was found that TiO2 photocatalytic activity essentially depends on adsorption interactions between the dye molecules and catalytic active centers on TiO2 surface, and these interactions, in turn, are greatly affected by pH of the solution.

PREPARATION OF POLYSULFONAMIDE/TiO_2 NANOCOMPOSITES BY SOL-GEL

Polysulfonamide(PSA)was synthesized at room temperature,the polymerization based on terephthaloyl chloride and 3,3’-diaminodiphenylsulfone in the common solvent N,N-Dimethyl-acetamide(DMAc).Polysulfonamide/titanium oxide nanocomposites were prepared by sol-gel method.Tetrabutyl titanate(TBT)was added into the polysulfonamide solution,at the same time,some water was mixed to make the TBT hydrolyze.In the process,hydrochloric acid was used to catalyze the reaction.The polysulfonamide chemistry structure was characterized by FT-IR spectrum.Atomic force microscopy(AFM)was employed to observe the microstructure of the composite film.The thermal property was investigated by TGA.The results show that we have succeeded to synthesize the polysulfonamide,TiO2 particles were well distributed in the composite film and average size was about 20 nm on average,the heat-resistance of nanocomposite was batter than the pure polysulfonamide.

Self-Organizing Evolution of Anodized Oxide Films on Ti-25Nb-3Mo-2Sn-3Zr Alloy and Hydrophilicity

In the present work,hierarchical nanostructured titanium dioxide(TiO2) films were fabricated on Ti-25Nb-3Mo-2Sn-3Zr(TLM) alloy for biomedical applications via one-step anodization process in ethylene glycolbased electrolyte containing 0.5wt% NH4F.The nanostructured TiO2 films exhibited three distinct types depending on the anodization time:top irregular nanopores(INP)/beneath regular nanopores(RNP),top INP/middle regular nanotubes(RNT)/bottom RNP and top RNT with underlying RNP.The evolution of the nanostructured TiO2 films with anodization time demonstrated that self-organizing nanopores formed at the very beginning and individual nanotubes originated from underlying nanopore dissolution.Furthermore,a modified two-stage self-organizing mechanism was introduced to illustrate the growth of the nanostructured TiO2 films.Compared with TLM titanium alloy matrix,the TiO2 films with special nano-structure hold better hydrophilicity and higher specific surface area,which lays the foundation for their biomedical applications.

Decomposition of formaldehyde based on gold-coated TiO2 nanoparticles

The synthesis of gold nanoparticles caped with visible light-responsible TiO2 nanoparticles. was prepared by using electrochemical Oxidation-Reduction Cycles （ORC） in 0.1 M HCI aqueous solution containing 60 mM visible light-responsible TiO2 nanoparticles. Firstly, an Au substrate was cycled in a deoxygenated aqueous solution containing 0.1 M HCI and 60 mM anatase TiO2 nanoparticles from -0.28 to ＋1.22 V vs Ag/AgCI at 500 mV/s with 25 scans. The durations at the cathodic and anodic vertexes are 10 and 5 s, respectively. After this process, Au-and TiO2-containing complexes were left in the solution. Then a Pt electrode immediately replaced the Au working electrode, and a cathodic overpotential of 0.6 V from the Open Circuit Potential （OCP） was applied under sonification to synthesize Au nanoparticles. Encouragingly, the prepared Au nanoparticles caped with visible light-responsible TiO2 nanoparticles are more active for the decomposition of formaldehyde than pure visible light-responsible TiO2 nanoparticles are in the same condition. After 5 days testing, the formaldehyde was decomposed ca. 35% in containing Au nanoparticles caped with visible light-responsible TiO2 nanoparticles, but the formaldehyde was decomposed only ca. 25% in containing pure visible light-responsible TiO2 nanoparticles.

Formation and capacitance properties of Ti-Al composite oxide film on aluminum

Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmission electron microscopy (TEM),Auger electron spectroscopy (AES),X-ray diffractometry (XRD) and electrochemical impedance spectroscopy (EIS).It was found that an anodic oxide film with a dual-layer structure formed between TiO2 coating and Al substrate.The film consisted of an inner Al2O3 layer and an outer Ti-Al composite oxide layer.The thickness of layers varied with the number of times of sol-gel dip-coating.The capacitance of anodic oxide films formed on coated specimens was at most 80% higher than that without TiO2.In film formation mechanism,it was claimed that the formation of composite oxide film was mainly affected by the structure of micro-pores network in TiO2 coating which had an influence on Al3+ and O2? ions transport during the anodizing.

可见光催化降解水中邻苯二甲酸二异辛酯的研究

邻苯二甲酸二异辛酯(DEHP)是环境激素类物质的一种,在环境中该物质持久存在不易分解,对人体健康造成严重危害,因此研究其废水降解具有重要的意义。以氙灯作为可见光光源,纳米CuPcTs/TiO2为催化剂,在可见光照射下较系统地考察了催化剂的活性、初始溶液的pH值、催化剂用量、光照时间等因素,对水溶液中DEHP光催化降解进行了研究。结果表明在pH=5,催化剂用量为0.4 g/L,光照时间为50 min,初始浓度为10 mg/L的DEHP水溶液降解速率为最佳,降解率达到93.6%,并证明了只有在催化剂和光源协同作用时,水中DEHP才可获得较快的降解。

Preparation of Li_4Ti_5O_(12) submicrospheres and their application as anode materials of rechargeable lithium-ion batteries

We report on the preparation of spinel Li4Ti5O12 submicrospheres and their application as anode materials of rechargeable lithium-ion batteries. The spinel Li4Ti5O12 submicrospheres are synthesized with three steps of the hydrolysis of TiCl4 to form rutile TiO2, the hydrothermal treatment of rutile TiO2 with LiOH to prepare an intermediate phase of LiTi2O4+δ, and the calcinations of LiTi2O4+δ to obtain spinel Li4Ti5O12. The as-prepared products are investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The diameters of Li4Ti5O12 submicrospheres with novel hierarchical microstructures are about 200–300 nm with the assembly of 20–30 nm nanoparticles. The electrochemical properties of Li4Ti5O12 submicrospheres are measured by galvanostatical discharge/charge test and cyclic voltammetry (CV). The as-prepared Li4Ti5O12 display excellent discharge/charge rate and cycling capability. A high discharge capacity of 174.3 mAh/g is obtained in the first discharge at 1 C rate. Meanwhile, there is only tiny capacity fading with nearly 100% columbic efficiency in the sequential 5–50 cycles. Moreover, lithium-ion diffusion coefficient in Li4Ti5O12 is calculated to be 1.03 × 10-7 cm2/s. The present results indicate that the as-prepared Li4Ti5O12 submicrospheres are promising anode candidates of rechargeable Li-ion batteries for high-power applications.

Novel Photodetectors Based on Double-Walled Carbon Nanotube Film/TiO2 Nanotube Array Heterodimensional Contacts

A new kind of photodetector based on a double-walled carbon nanotube （DWCNT） film and a TiO2 nanotube array with hetrodimensional non-ohmic contacts has been fabricated. Due to the dimensionality difference effect, the DWCNT film/TiO2 nanotube array photodetector exhibits a much higher photocurrent-to-dark current ratio and photoresponse relative to an Au film/TiO2 nanotube array device, even at small bias voltage. The photocurrent-to-dark current ratio reached four orders of magnitude and a high photoresponse of 2467 A/W was found upon irradiation at 340 nm. Furthermore, the photosensitive regions could be extended into the visible range. The photocurrent-to-dark current ratio reached approximately three orders of magnitude upon irradiation at 532 nm, where the photon energy is much lower than the band gap of TiO2.

Efficiency improvement of flexible dye-sensitized solar cells by introducing mesoporous TiO_2 microsphere

Mesoporous TiO2microsphere(MTM)was synthesized via a simple solution route and then mixed with commercial TiO2(P25)to form highly homogeneous and stable TiO2colloid by simple hydrothermal treatment.The TiO2colloid was coated onto the plastic conductive substrate to prepare mesoporous TiO2film for flexible dye-sensitized solar cells(DSSCs)by low-temperature heat treatment.The influence of MTM content on the physicochemical properties of the flexible TiO2film was characterized by scanning electron microscope,transmission electron microscopy,X-ray diffraction,energy-dispersive X-ray spectrometer,N2adsorption-desorption isotherms,UV–vis absorption and diffuse reflectance spectra.It is revealed that with increasing the MTM content,the dye-loading capability of TiO2film and light-harvesting efficiency of flexible DSSCs are improved due to MTM having high surface area and acting as a light scattering center,respectively,resulting in the enhancement of photocurrent of flexible DSSCs.However,more and larger cracks having negative effect on the performances of flexible DSSCs are formed simultaneously.Under the optimal condition with MTM content of 20%,a flexible DSSC with overall light-to-electric energy conversion efficiency of 2.74%is achieved under a simulated solar light irradiation of 100 mW cm 2(AM 1.5),with 26%improvement in comparison with DSSCs based on P25 alone.

Fabrication of periodically aligned vertical singlecrystalline anatase TiO2 nanotubes with perfect hexagonal open-ends using chemical capping materials

A vertically aligned anatase TiO2 （A-TiO2） nanotube array has been fabricated by coating a ZnO nanorod （NR） template with a TiO2 precursor solution. After coating, the ZnO NR cores were selectively etched in an acidic environment to form TiO2 nanotubes （NTs）. More specifically, after growing the ZnO NRs via a hydrothermal method, one drop of the TiO2 precursor solution was cast to coat the ZnO NRs, the tops of which were previously covered with chemical capping materials by electrostatic interaction, and then the sample was sintered. Finally, the sample was immersed in an acidic solution resulting in selective etching of the ZnO NR cores. Thus, only TiO2 NTs remained on the substrate. The capping material is effectively used to create a perfect, hexagonal open-ended TiO2 NT array, which interestingly extends onset absorption towards the visible region.

Synthesis of TiO_2 photocatalysts with abundant surface defects using a TiO_2@NaCl precursor

TiO2 nanoparticles have been synthesized by using a TiO2@NaCl core-shell structure as the precursor. The surface defects were well preserved by the NaCl shell, and therefore high oxygen adsorption capacity was observed. After the NaC1 shell was removed, the resulting pure TiO2 nanoparticles were of anatase phase and uniform size of around 20-24 nm. The presence of an abundance of surface defects contributes to the high photocatalytic activity of the synthesized materials, and the TiO： mate- rials obtained from the TiO2@NaCl precursor can be used as efficient photocatalysts for degradation of rhodamine B under UV light irradiation.

Controllable hydrothermal synthesis of nanocrystal TiO_2 particles and their use in dye-sensitized solar cells

A simple method for the controllable hydrothermal synthesis of nanocrystalline anatase TiO2(nc-TiO2) particles involving the selection of suitable organic alkali peptizing agents is reported.A dye-sensitized solar cell(DSSC) with square-like nc-TiO2 particles with side lengths about 8-13 nm-prepared using tetraethylammonium hydroxide(TEAOH)-in the photoelectrode showed higher photovoltaic performance than two other DSSCs with square-like nc-TiO2 particles with side lengths about 7-10 nm-prepared using tetrabutylammonium hydroxide-or elongated nc-TiO2 particles with lengths about 18-35 nm and width about 10 18 nm-prepared using tetramethylammonium hydroxide(TMAOH)-in the photoelectrodes.When a scattering layer prepared from sub-micron size spheres or cone-like nc-TiO2 particles-synthesized using a higher concentration of TMAOH-was added on top of the photoelectrode fabricated from nc-TiO2 synthesized with TEAOH,the energy conversion efficiency of the DSSC was markedly increased from 6.77% to 8.18%.

Multicycle photocatalytic reduction of Cr(Ⅵ) over transparent PVA/TiO_2 nanocomposite films under visible light

Photocatalytic reduction of hexavalent chromium in wastewater has been widely investigated as an attractive treatment method. In this work, we reported an efficient method for photocatalytic reduction of Cr（VI） over transparent polyvinyl alcohol/titanium dioxide （PVA/TiO2） nanocomposite films under sunlight irradiation. The trans- parent PVA/TiO2 nanocomposite films were prepared by a simple hydrothermal method combined with a solution casting process. The results revealed that the anatase TiO2 nanoparticles with size less than 10 nm were in-situ generated in PVA matrix, which endowed the films with high trans- parency. Photocatalytic reduction of Cr（VI） over PVA/TiO2 nanocomposite films exhibited superior visible light pho- tocatalytic activity. Mechanism investigation demonstrated that the PVA acted not only as a transparent support for TiO2 nanoparticles, but also as holes scavengers simultaneously to improve the separation of photogenerated holes and elec- trons. Meanwhile, the transparent PVA/TiO2 nanocomposite films displayed remarkable stability and excellent recyclabil- ity during multicycle Cr（VI） photoreduction. Furthermore, the PVA/TiO2 nanocomposite films showed selective adsorp- tion ability for Cr（III）, and thus totally removal of Cr（VI） was achieved after photoreduction process.