Preparation of Zn-doped TiO2 nanotubes electrode and its application in pentachlorophenol photoelectrocatalytic degradation

Zn-doped titanium oxide （TiO2） nanotubes electrode was prepared on a titanium plate by direct anodic oxidation and immersing method in sequence. Field emission scanning electron microscopy （FESEM） showed that the Zn-doped TiO2 nanotubes were well aligned and organized into high density uniform arrays with diameter ranging from 50 to 90 nm. The length and the thickness were about 200 and 15 nm respectively. TiO2 anatase phase was identified by X-ray diffraction （XRD）. X-ray photoelectronspectroscopy （XPS） indicated that Zn ions were mainly located on the surface of TiO2 nanotubes in form of ZnO clusters. Compared with TiO2 nanotubes electrode, about 20 nm red shift in the spectrum of UV-vis absorption was observed. The degradation of pentachlorophenol （PCP） in aqueous solution under the same condition （initial concentration of PCP： 20 mg/L; concentration of Na2SO4：0.01 mol/L and pH： 7.03） was carried out using Zn-doped TiO2 nanotubes electrode and TiO2 nanotubes electrode. The degradation rates of PCP using Zn-doped TiO2 nanotubes electrode were found to be twice and 5.8 times as high as that using TiO2 nanotubes electrode by UV radiation （400 μw/cm^2） and visible light radiation （4500 μw/cm^2）, respectively. 73.5% of PCP was removed using Zn-doped TiO2 nanotubes electrode against 45.5% removed using TiO2 nanotubes electrode in 120 min under UV radiation. While under visible light radiation, the degradation efficiency of PCP was 18.4% using Zn-doped TiO2 nanotubes electrode against 3.2% using TiO2 nanotubes electrode in 120 min. The optimum concentration of Zn doping was found to be 0.909%. The PCP degradation efficiencies of the 10 repeated experiments by Zn-doped TiO2 nanotubes electrode were rather stable with the deviation within 3.0%.     

I-doping of anodized TiO<Subscript>2</Subscript> nanotubes using an electrochemical method

In order to obtain TiO2 with high photocatalytic activity, a cathode reduction was used to dope I⁷⁺ and I⁵⁺ into TiO₂ nanotubes of anodized Ti in C₂H₂O₄•2H₂O + NH₄F electrolyte. SEM images show that the anodization method integrated the preparation with the doping process, which for nonmetals-doping is advantageous to maintain the morphological integrity of TiO₂ nanotubes. I⁷⁺-I⁵⁺-doping enhances the UV response of TiO₂ and result in a red-shift. Under UV/visible irradiation, a I⁷⁺-I⁵⁺-doped sample (400°C) showed the highest I_ph and photocatalytic efficiency. A part of I^– in the I⁷⁺-I⁵⁺-doped sample is involved in the UV response, the red-shift and the higher I_ph.     

Fabrication of visible-light responsive S-F-codoped TiO<Subscript>2</Subscript> nanotubes

Fabrication and S-F-codoping of TiO2 nanotubes were carried out by a one-step electrochemical anodization process to extend the photoresponse of TiO2 to the visible-light region. The prepared samples were annealed in air and detected by SEM, XRD, XPS and UV-vis DRS spectrophotometer. The results showed that the average tube diameter of the nanotubes was 150 nm and the average tube length was 400 nm. The doped TiO2 nanotubes exhibited strong absorption in visible-light region. Photoelectrocatalytic degradation efficiency of 4-CP over S-F-codoped TiO2 nanotubes was 39.7% higher than that of only-F-doped sample. Moreover, sulfur and fluorine codoped into substitutional sites of TiO2 had been proven to be indispensable for strong response and high photocatalytic activity under visible light, as assessed by XPS.     

TiO2光催化降解印染废水的研究

研究了实际印染废水的TiO     

A review on TiO2 nanotube arrays: Fabrication, properties, and sensing applications

Fabrication, properties, and sensing applications of TiO₂ nanotubes have been reviewed, and the highly ordered TiO₂ nanotube arrays made by anodic oxidation in fluoride-contained electrolytes highlighted. The effect of anodization parameters (electrolyte, pH, and voltage) on the titania nanotube size and shape were discussed. The excellent biocompatibility of TiO₂, the high orientation, the large surface area with tunable pore sizes, as well as the high electron transfer rate along with the nanotubes make TiO₂ nanotube array an ideal substrate for the sensor’s fabrication and application. The sensors based on the TiO₂ nanotube arrays for sensing hydrogen, oxygen, humidity, glucose and hydrogen peroxide all exhibited low detection limit, high stability, very good reproducibility and high sensitivity.     

Modification of TiO2 nanotubes arrays by CdS and their photoelectrocatalytic hydrogen generation properties

In order to realize hydrogen generation under visible light, novel CdS/TiO2 nanotubes arrays are developed by electrochemical anodizaUon of Ti in 0.15 mol/L NHTF ＋ 0.08 mol/L H2C2O4 electrolyte. The diameter of the nanotube is 80-100 nm and the length is approximately 550 nm. The CdS nano-particles are deposited on the TiO2 nanotubes arrays by chemical bath deposition （CBD） in the ammonia-thiourea system. A 300 W Xe lamp is used as the light source, CdS/TiO2 nanotube arrays are used as the photoanode with the application of 1.0 V bath voltage, and 0.1 mol/L Na2S ＋ 0.04 mol/L Na2SO3 solution is used as the electrolyte, then the rate of photoelectrocatalytic hydrogen generation is 245.4 μL/（h·cm^2）. This opens new perspectives for photoelectrocatalytic hydrogen generation by using CdS/TiO2 nanotubes arrays.     

Photoelectrochemical synergetic degradation of Acid Orange II with TiO2 modified β-PbO2 electrode

Electrochemically assisted photocatalysis is an effective approach to improve photocatalytic efficiency. In this paper, modified β-PbO2 electrode was prepared by TiO2 co-deposition and characterized by SEM and XRD. Then 2.0g TiO2 modified β-PbO2 electrode (2.0 g TiO2 involved in the 200 mL co-deposition solution) was used in electrochemically assisted photocatalytic degradation of Acid Orange II and the influence of initial pH values was investigated when the potential applied across the electrodes was 1.5 V. When the potential applied was 2.5 V, the difference of the degradation process and the final products were studied. The results indicated that 2.0 g TiO2 modified β-PbO2 electrode was different from the unmodified one in that the β-PbO2 crystals became finer and the electrode became more compact and more uniform. The synergetic effect in electrochemically assisted photocatalytic degradation of Acid Orange Ⅱ was observed and degradation efficiency and TOC removal were the highest at initial solution pH 2.0. By UV-visible spectral analysis, it was proved that photoelectrochemical synergetic degradation of Acid Orange Ⅱ went through the step of producing main product maleic acid for the solution at the initial pH 2.0 within 2 h, but the degradation was slow for the solution at the initial pH 12.0.     

Photocatalytic degradation of trace-level of MicrocystinLR by nano-film of titanium dioxide

The occurrence of toxic water bloom of cyanobacte-ria algae, widely reported in eutrophic freshwater, hasbeen a serious pollution problem in recent years[1]. Mi-crocystins (MCs), the most common cyanobacteriatoxin with a cyclic heptapeptide structure (Fig…     

LaVO4/TiO2在分解甲基橙中的光催化性能研究

光催化剂TiO₂在污水有机物降解中有着巨大优势,但由于对光的利用率过低,需要在TiO₂的基础上进行掺杂来改善其光催化性能。本研究利用稀土镧元素对TiO₂进行了掺杂分别制备了LaVO₄/TiO₂和La(NO₃)₃/TiO₂复合光催化剂,并将它们应用于甲基橙的光催化降解反应,证实了LaVO₄对TiO₂的光催化效果有较明显的增强作用。另外还研究了不同pH条件制备和不同掺杂比例的LaVO₄/TiO₂光催化效果,pH在10.56左右制备出的LaVO₄和掺杂比例为5%的LaVO₄制得的LaVO₄/TiO₂复合光催化剂效果较好。     

Photocatalytic degradation pathways and adsorption modes of H-acid in TiO2 suspensions

Effect of adsorption mode on photodegradation of H-acid in TiO2 suspension was studied using DFT calculation,UV-Vis spec-troscopy,FTIR,and ionic chromatography.At pH 2.5,H-acid was adsorbed on TiO2 surfaces by one dissociated sulfonic group.The adsorbed sulfonic group was attacked by surface ·OH,resulting in the production of SO42-and the cleavage of the naphtha-lene ring.At pH 5.0,H-acid was adsorbed on TiO2 surfaces by two sulfonic groups.The two adsorbed sulfonic groups were sim-ultaneously attacked by surface ·OH,leading to a faster initial production of SO42-and initial degradation rate of H-acid than those under pH 2.5.Microscopic adsorption structures may be more important than adsorption amount in controlling the photo-degradation pathways of organic pollutants.     

Synthesis of SnO2TiO2 nanocomposite photocatalysts by supercritical fluid combination technology

Acrylic acid, acrylic ester and their ramification have developed quickly in recent years. However, their pro duction process produces a mass of waste water, which when released into the aquatic ecosystem, becomes a source of dramatic disturbance of aquat…     

Fe_2O_3/TiO_2复合纳米管阵列的制备及其可见光催化性能研究

在氟化铵-乙二醇体系中,采用阳极氧化法在铁基体上制备Fe_2O_3纳米管阵列,然后以氟钛酸铵为钛源,利用水热法在Fe_2O_3纳米管阵列上负载TiO_2纳米片,制得Fe_2O_3/TiO_2复合纳米管阵列,利用SEM、EDS、XRD、TEM、UV-Vis等手段,对所制Fe_2O_3/TiO_2纳米管阵列的表面形貌、物相结构及光催化性能进行表征,并分析Fe_2O_3/TiO_2纳米结构对亚甲基蓝的可见光降解能力。结果表明,Fe_2O_3/TiO_2复合纳米管阵列具有良好的可见光响应;NH_4F浓度为0.4%、水热反应3h制备的Fe_2O_3/TiO_2复合结构具有最佳的光催化性能,对亚甲基蓝的降解率可达90%。     

Array of single crystalline anatase TiO2 nanotubes with significant enhancement of photoresponse

Anatase TiO₂ nanotubes array(ATONA) has attracted tremendous attention owing to its promising applications in solar cells, water splitting and organic pollutants photocatalytic degradation. However, the activity of ATONAs was greatly suppressed by the grain boundaries existed in the tube walls, which acted as carrier scattering and recombination centers. Herein, we report a novel strategy to prepare array of single crystalline anatase TiO₂ nanotubes(SC-ATONAs) with signific...     

Layered Fe（Ⅲ） doped TiO2 thin-film electrodes for the photoelectrocatalytic oxidation of glucose and potassium hydrogen phthalate

Four types of TiO 2 thin-film electrodes were fabricated from TiO 2 and Fe(III) doped TiO 2 sols using a layer-by-layer dip-coating technique. Electrodes fabricated were TF (pure TiO 2 surface, Fe(III)-TiO 2 bottom layer), FT (Fe(III)-TiO 2 surface, pure TiO 2 bottom layer), TT (both layers pure TiO 2 ) and FF (both layers Fe(III)-TiO 2 ). The photoelectrochemical behavior of these electrodes was characterized using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and steady-state photocurrent measurements in aqueous 0.1 mol L –1 NaNO 3 containing varying concentrations of glucose or potassium hydrogen phthalate (KHP). EIS and LSV results revealed that exciton separation efficiency followed the sequence of TF﹥TT﹥FT > FF. Under a constant potential of +0.3 V, steady-state photocurrent profiles were recorded with varying organic compound concentrations. The TF electrode possessed the greatest photocatalytic capacity for oxidizing glucose and KHP, and possessed a KHP anti-poisoning effect. Enhanced photoelectrochemical performance of the TF electrode was attributed to effective exciton separation because of the layered TF structure.     

The hemocompatibility and the reabsorption function of TiO2 nanotubes biomembranes

A novel high-intensity TiO2 nanotubes array membrane was fabricated via electrochemical anodization of highly pure titanium foil and an open-ended TiO2 nanotubes array membrane was obtained by HF gas etching at the bottom of the nanotubes. Pig tubular epithelial cells (LLC-PK1) and vascular endothelial cells (ECV304) were cultivated on the open-ended TiO2 nanotubes surface through a mixing implantation method and TiO2 nanotubes biomembrane materials with physiological function were successfully produced. Hemocompatibility of glass slides, pure titanium, TiO2 nanotubes without cells and TiO2 nanotubes with culture cells were investigated by the plasma recalcification time method and reabsorption of sodium and potassium were measured by custom-designed devices. The results show that the hemocompatibility of the TiO2 nanotubes array membrane with culture cells was superior to the control group, and the biomembrane has an excellent reabsorption function. This demonstrates that a TiO2 nanotubes array membrane has excellent physiological function and is an ideal candidate material for biological dialysis.     

银掺杂多孔氧化钛光催化甲基橙降解反应条件的探究

利用溶胶-凝胶法结合光还原法制备Ag掺杂多孔TiO_2光催化剂,以甲基橙的降解效果为评价标准,考查了光照降解时间、光催化剂用量、甲基橙溶液初始浓度、溶液pH值对光催化剂催化降解甲基橙的影响。结果表明,本方法制备的光催化剂无论是在紫外光还是可见光下均具有优良的光催化性能:在浓度为10 mg/L的甲基橙溶液中,4 g/L光催化剂,紫外光照射80 min,甲基橙可实现100%完全降解;相同催化条件下,可见光照100 min,甲基橙完全降解;当反应溶液pH=2时,紫外光和可见光都可在20 min内实现甲基橙的完全降解。     

Enhanced photocatalytic degradation of tetracycline hydrochloride by molecular imprinted film modified TiO<Subscript>2</Subscript> nanotubes

To enhance the photocatalytic activity of TiO2 nanotubes,tetracycline hydrochloride(TC) molecularly imprinted titania modified TiO2 nanotubes(MIP-TiO2) was prepared by liquid phase deposition,which improved the molecular recognition ability of the photocatalyst toward template molecules.This MIP-TiO2 photocatalyst was characterized by ESEM and XRD,which showed that the imprinted titania was deposited on the nanotube uniformly and was of well-crystalized anatase-type.In the adsorption experiments,MIP-TiO2 exhibited a high adsorption capacity(about 1.6 times higher than that of TiO2 nanotubes) for TC mainly because of its imprinted sites and high surface area.Under UV irradiation MIP-TiO2 showed enhanced photocatalytic activity with an apparent first-order rate constant 1.9-fold that of TiO 2 nanotubes.     

Degradation of 2, 4-D acid using Mn2+ as catalyst under UV irradiation

In this paper, the oxidative degradation of 2, 4-dichlorophenoxyacetic acid (2, 4-D) using Mn²⁺/H₂O₂ reagent under UV irradiation was studied. The results show that 2, 4-D was degraded more completely in Mn²⁺/H₂O₂ solution than traditional Fenton solutions. The effects of the concentration of Mn²⁺, H₂O₂ and pH were also investigated. And under the optimal condition of 1.48×10⁻⁴ mol/L, 8.99×10⁻⁵ mol/L and pH 3.38, the formation of ·OH was the most, both the decomposition rate of H₂O₂ and the degradation rate of 2, 4-D were the fastest. In addition, the photoreaction process was monitored using spin-trapping electron paramagnetic resonance (EPR), and the results indicated that the oxidative process was predominated mainly by the hydroxyl radical (·OH) gennerated in the system. Biography: HUANG Yingping (1964–), Professor, Ph. D., research direction: pollution ecology and water pollution control.     

Carboxyl-modified hierarchical wrinkled mesoporous silica supported TiO2 nanocomposite particles with excellent photocatalytic performances

Titanium dioxide (TiO₂) is a common photocatalyst for organic pollutants degradation. However, in practical application, the poor adsorption capacity of pure TiO₂ seriously impeded its efficiency in the degradation of organic molecules. In this work, a series of hierarchical wrinkle mesoporous silica supported TiO₂ nano-composite particles (TiO₂ @WMS-COOH) were successfully prepared. Thanks to their high surface areas, large pore volumes and mesoporous structures, these materials showed high adsorption capacity and excellent photocatalytic performance towards dye molecules, which is comparable to or even better than commercial catalyst P25. Moreover, their photocatalytic efficiency can be further enhanced by increasing the calcination temperature during preparation process. Therefore it can be concluded that the TiO₂ @WMS-COOH particles may find promising applications in the photodegradation of organic pollutants.     

Preparation and characterization of in-site regenerated TiO<Subscript>2</Subscript>-ACFs photocatalyst

In-site regenerated titanium dioxide-activated carbon fibers (TiO₂-ACFs) photocatalyst was prepared by the sol-gel method. Detailed surface and structural characterization of the TiO₂-ACFs photocatalyst was carried out. The photoactivity of TiO₂-ACFs under ultraviolet irradiation was compared with original ACFs and pure TiO₂ by the degradation of methylene blue aqueous solution. The degradation efficiency by the TiO₂ (5wt%)-ACFs sample is much higher than that by TiO₂ and ACFs. The results show that the photocatalysis by TiO₂-ACFs is a six-step process. The adsorption-transfer-photocatalysis rate of TiO₂-ACFs is higher than the adsorption-photocatalysis rate of TiO₂, so the photocatalysis rate of the TiO₂-ACFs system is higher than that of TiO₂ photocatalyst.