可见光下Rhodamine B在钴掺杂TiO2薄膜上的光催化降解

采用溶胶 凝胶法和涂覆成膜技术在钛片上制备了有可见光响应的Co2+掺杂TiO2薄膜(Co-TiO2).应用该薄膜光催化剂在可见光下进行了Rhodamine B（RhB）的光降解研究.结果表明，当Co2+的掺杂摩尔分数为0.02％时，光催化剂对RhB有最佳的光降解效果，而且在降解过程中存在光催化和光敏化的协同效应；同时在酸性体系中光降解RhB比在碱性体系中有较快的速率和较小的最大吸收峰位移，这可能与不同pH下，TiO2表面的荷电状态影响光降解过程有关.Co-TiO2光催化剂的使用，成功地实现了可见光下对RhB的光催化和光敏化协同降解，提高了可见光下RhB的光降解速率.     

Synthesis of novel CaCO_3/Ag_2CO_3/Ag I/Ag plasmonic photocatalyst with enhanced visible light photocatalytic activity.

In this work, novel Ca CO3/Ag2CO3/Ag I/Ag plasmonic photocatalysts were successfully synthesized by a two-step in situ ion exchange process and their photocatalytic properties were studied. The morphology, crystal structure and optical properties of the as-prepared Ca CO3/Ag2CO3/Ag I/Ag nanocomposites were characterized by transmission electron microscopy(TEM), XRay diffraction(XRD), and UV-vis diffuse reflectance spectroscopy. The photocatalytic activity of the obtained nanocomposites was evaluated by the photodegradation of methyl orange(MO) under visible light irradiation. It was found that the as-prepared Ca CO3/Ag2CO3/Ag I/Ag plasmonic photocatalyst exhibits high visible light photocatalytic activity. With an optimized composition, MO dye can be decomposed by more than 94% within 15 min under visible light irradiation. Moreover, the photocatalytic stability could be greatly improved upon the addition of Na2CO3 into the photocatalytic system. From the proposed photocatalytic mechanism, the strong surface plasmon resonance effect of Ag nanoparticles and the efficient separation of photogenerated electrons and holes can effectively enhance the photocatalytic performance of the Ca CO3/Ag2CO3/ Ag I/Ag composites.     

新型铈掺杂氧化铋复合催化材料制备及其光催化性能研究

基于静电纺丝技术将金属Ce掺杂到Bi₂O₃中,研究制备出了光催化活性增强的新型一维线性复合催化剂,并通过XRD、SEM、TEM、UV vis-DRS表征与分析,研究了不同掺杂比例对Bi₂O₃改性的影响,并将自制的光催化剂应用于液相中光降解甲基橙染料有机物,以甲基橙为目标降解物,研究结果表明,金属Ce成功地掺杂到Bi₂O₃中替换了部分Bi的晶格位,其中掺杂比例为0.25时获得了最佳的可见光催化活性,其吸收边红移最大,增禁带宽度为2.22 eV,可见光照射下90min对MO催化降解率达到98.81%,光降解过程符合一级动学过程,光催化剂可见光催化降解有机污染物性能优良。研究结果为新型铈掺杂氧化铋复合催化材料在光催化领域内处理难生物降解污染物提供理论依据和技术支持。     

ZnO-chitosan/Rectorite Nanocomposite Exhibiting High Photocatalytic Activities under Visible-light Irradiation

Chitosan(CS),hydrated zinc acetate,and rectorite(REC) were used as raw materials to prepare CS-embedded zinc oxide(ZnO) nanoparticle by a chemical precipitation process.Hydrogen-bonded REC-loaded ZnO-CS nanoparticle was to form ZnO-CS/REC nanocomposite photocatalyst,its morphology and structure were analyzed by means of FTIR,XRD,TGA,SEM,and TEM.The effects of the catalyst dosage,methyl orange(MO) initial concentration and solution pH on photocatalytic performance were also discussed.The experimental results show that the ZnO-CS/REC nanocomposite has a particle size of 100 nm with good dispersion and uniformity.Under irradiation of visible light,0.6 g/L photocatalyst was used to degrade MO in solution for 90 min at pH 6,then the MO solution(10 mg/L) was decolored by more than 99%,indicating that the ZnO-CS/REC nanocomposite exhibited highly photocatalytic degradation activity.Therefore,the photodegradation kinetic mechanism of MO in aqueous solution is presumed.     

掺杂金属卟啉的TiO_2薄膜对活性艳红X-3B染料的光催化降解性能

采用溶胶凝胶的方法,将具有高光敏性的四(对羟基)苯基锌卟啉(ZnTHPP,下简称锌卟啉)在钛酸丁酯[Ti(OBu)4]水解的条件下均匀嵌入到了TiO2无机网络中,又采用旋涂法制备了ZnTHPP/TiO2复合薄膜。利用UV Vis吸收光谱对薄膜的紫外可见光吸收性质进行了研究,结果表明锌卟啉的加入能有效的拓宽TiO2的可见光吸收范围。通过光催化降解活性艳红X 3B染料实验,对所制备的ZnTHPP/TiO2复合薄膜的光催化活性进行了考察,研究发现以ZnTHPP/TiO2作为光催化剂对活性艳红X 3B染料能有效的降解,表现出了较好的可见光催化活性。     

Preparation of V-doped TiO2 photocatalysts by the solution combustion method and their visible light photocatalysis activities

A series of nanocrystalline V-doped （0.0-3.0 at.%） TiO2 catalysts have been successfully prepared by the one-step solution combustion method using urea as a fuel. The obtained powders were characterized by XRD, SEM, Raman, XPS and UV-Vis DRS. The effects of V doping concentration on the phase structure and photocatalytic properties were investigated. XRD, Raman, and XPS show that V doping diffuses into TiO2 crystal lattice mainly in the form of V5＋ and causes a phase transition from anatase to mille. V doping can widen the light absorption range of TiO2, with the absorption threshold wavelength shifting from 425 to 625 nm. The photocatalytic activity of V-doped TiO2 powders were evaluated by the photocatalytic degradation of methyl orange （MO） under visible light irradiation. It is found that V doping enhances the photoeatalyilc activity under visible light irradiation and the optimal degradation rate of MO is about 95.8% with 1.0 at% V-doped TiO2.     

Enhanced photocatalytic degradation of methyl orange by CdS quantum dots sensitized platelike WO_3 photoelectrodes

CdS quantum dots sensitized platelike WO_3 photoelectrodes were successfully synthesized by a facile hydrothermal method and a modified chemical bath deposition(CBD) technique.To further improve the stability of the photoelectrodes in alkaline environment,the platelike WO_3 films were treated with TiCl_4 to form a nano-TiO_2 buffer layer on the WO_3 plate surface before loading CdSQDs.The resulting electrodes were characterized by using XRD,SEM,HR-TEM and UV-vis spectrum.The photocatalytic activity of the resulting electrodes was investigated by degradation of methyl orange(MO) in aqueous solution.The photoelectrochemical(PEC) property of the resulting electrodes was also characterized by the linear sweep voltammetry.The results of both the degradation of MO and photocurrent tests indicated that the as-prepared CdSQDs sensitized WO_3 platelike photoelectrodes exhibit a significant improvement in photocatalytic degradation and PEC activity under visible light irradiation,compared with unsupported CdSQDs electrodes.Significantly,coating the WO_3 plates with nano-TiO_2 obviously facilitate the charge separation and retards the charge-pair recombination,and results in a highest activity for QDsCdS/TiO_2/WO_3 photoelectrodes.     

Facile synthesis of mesoporous cuprous oxide nanoparticles for enhanced visible-light-driven photodegradation

The visible-light-active mesoporous cuprous oxide nanoparticles were successfully synthesized via a facile precipitation process with the presence of gelatin, which was demonstrated to play an important role in the formation of mesoporous structure and the grain size control. The nanoscale grain size and mesoporous structure lead to lager specific surface area with the addition of gelatin. Furthermore, the photodegradation of as-prepared catalysts in the presence of gelatin toward the negatively charged methyl orange (MO) was investigated. The cuprous oxide displayed an excellent visible light photocatalytic activity of MO, owing to its exposed active (111) face and large specific surface area. The adsorption of positively charged methyl blue (MB) revealed that the mesoporous cuprous oxide displayed better adsorption of anionic dye MB due to the residual gelatin on the surface of the grains, compared to that in the absence of gelatin.     

金属酞菁敏化二氧化钛可见光催化降解染料废水的研究

研究了染料敏化半导体光催化剂-酞菁镁/TiO_2复合粒子在可见光波段的光催化性能.通过溶胶-凝胶的方法制得TiO_2胶体再进行焙烧,得到二氧化钛粉末和薄膜,再用酞菁镁敏化,制得酞菁镁/TiO_2复合粒子.利用X射线衍射、扫描电子显微镜、红外光谱和X光电子能谱分析等方法对TiO_2和酞菁镁/TiO_2复合粒子的物理性质进行了表征;并以亚甲基蓝作为目标物研究其光催化性能.结果表明,酞菁镁可以敏化二氧化钛,使其吸收波长红移,并具有较好的光催化性能.     

Photogenerated carrier transfer mechanism and photocatalysis properties of TiO2 sensitized by Zn（ Ⅱ ） phthalocyanine

The Zn(Ⅱ) phthalocyanine sensitized TiO2(ZnPc-TiO2) nanoparticles were prepared by hydrothermal method via impregnation with ZnPc.The as-prepared photocatalysts were characterized by X-ray diffractometry(XRD) and diffuse reflectance spectroscopy(DRS),and the surface photovoltage spectroscopy(SPS) and photocatalytic degradation of rhodamine B(RhB) were studied under illuminating.The experimental results indicate that TiO2 sensitized by ZnPc extends its absorption band into the visible region effectively,and ...     

Preparation, characterization and photocatalytic activity of N-doped TiO_2 nanocrystals

N-doped TiO_2 nanocrystals were prepared using titanium alkoxide as precipitant with different proportional materials. The products were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy, and UV-vis diffuse reflectance spectra. It is confirmed experimentally that the photocatalytic activity of N-doped TiO_2 is much higher than that of Degussa P25, when used for the degradation of crystal violet.The degradation kinetics follows an apparent first-order reaction,which is consistent with a generally observed Langmuir-Hinshelwood mechanism. The doping of TiO_2 with nitrogen significantly increases the absorption in the region of visible light. The energy of the band gap of N-doped TiO_2 is 2.92 eV. The better performante of N-doped TiO_2 can be explained by the fact that it is also excited with longer-wavelength light.     

Visible Light-induced Cr-doped SrTiO_3-g-C_3N_4 Composite for Improved Photocatalytic Performance

Novel visible light-induced Cr-doped Sr Ti O3-g-C3N4 composite photocatalysts were synthesized by introducing polymeric g-C3N4. The composite photocatalyst was characterized by X-ray diffraction(XRD), high-resolution transmission electron microscopy(HRTEM), Fourier transform infrared(FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, photoluminescence(PL) spectroscopy and BET surface area measurements. The photocatalytic oxidation ability of the novel composite photocatalyst was evaluated using methyl orange(MO) as a target pollutant. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO. The optimal g-C3N4 content for the photodegradation activity of the composite photocatalysts was determined. The as-prepared composite photocatalyst exhibits an improved photocatalytic activity due to enhancement of photo-generated electron-hole separation at the interface.     

Fabrication and Photocatalytic Activity of Ag_3PO_4-TiO_2 Heterostructural Nanotube Arrays

To extend the absorption capability of TiO_2 into visible light region and inhibit the recombination of photogenerated electrons and holes,we put forward an effective strategy of the coupling of TiO_2 with a suitable semiconductor that possesses a narrow band gap.Meanwhile,Ag_3PO_4-TiO_2 heterostructuralnanotube arrays were prepared by the two-step anodic oxidation to obtain the TiO_2 nanotube arrays and then by a deposition-precipitation method to load Ag_3PO_4.The samples were characterized by field emission scanning electron microscopy(FESEM),energy dispersive spectrometry(EDS),X-ray diffraction(XRD),and UV-vis diffuse reflectance spectroscopy(UV-vis DRS).The experimentalresults showed that Ag_3PO_4 nanoparticles were uniformly dispersed on the highly ordered TiO_2 nanotube arrays,which increased the visible-light absorption of TiO_2 photocatalyst.The photocurrent density and photocatalytic degradation of methylorange indicated that the performance of Ag_3PO_4-TiO_2 heterostructuralnanotube arrays was better than that of the TiO_2 nanotube arrays,which could be attributed to the effective electron-hole separation and the improved utilization of visible light.     

Chemical-bonds Conjugated SnO_2/AgIO_4 Hybrids for Degradation of High Concentration Rhodamin B under Visible Light Illumination

SnO_2/AgIO_4 hybrids were fabricated by an in-situ synthetic method at room temperature. The structure, morphology, light response range, separation efficiency of the electron-hole pairs and elements of the as-synthesized samples were characterized by adopting X-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy, respectively. The synergistically photocatalytic degradation mechanism of the as-synthesized composites was also proposed. The experimental results reveal that under the visible light irradiation the as-synthesized SnO_2/AgIO_4 hybrids can enhance the photocatalytic degradation efficiency of rhodamine B compared to pure samples. With increasing the molar ratios of AgIO_4 to SnO_2, it displays the trend of first increasing and then decreasing. When it is 1:2 in 150 min, the as-prepared hybrids have the highest degradation efficiency of 93.1%, which increases by 6550.0%, 30.5%, and 1505.0% compared to those of pure SnO_2, AgIO_4, and TiO_2(P25), respectively. Moreover, the Sn-O-Ag cross-linking bonds are formed at the interfaces of SnO_2 and AgIO_4. In addition, superoxide anion radicals and holes play a major role in the process of photodegradation.     

可见光催化剂Ag_3VO_4的制备、表征及其光催化性能的研究

通过化学沉淀的方法来制备光催化剂Ag3VO4,用紫外-可见光谱、X射线衍射和荧光光谱对其进行表征.通过光催化还原Cr6＋和光催化氧化甲基橙的效率来评价该催化剂的活性.实验研究了不同的制备条件对Ag3VO4催化活性的影响.实验结果表明,在可见光下,在过量银条件下制备的Ag3VO4有较好的光催化氧化活性和光催化还原活性,且其紫外-可见吸收光谱有较大程度的红移,提高了对光的利用率.实验同时还研究了在过量银条件下制备出的Ag3VO4的稳定性和循环次数.同时对影响Ag3VO4的光催化活性的机理还进行了探讨.     

载银TiO2/沸石催化剂的制备、表征以及光催化性能的研究

为获得高活性的负载型TiO2光催化剂，通过硝酸银溶液浸渍-紫外光照的方法获得载银的TiO2/沸石催化剂.银改 性的TiO2/沸石催化剂光催化性能较改性前大大提高.最佳硝酸银浸渍液浓度为10-3mol/L,此时该催化剂的光催化性能接 近纳米TiO2粉末（Degussa P25）,但进一步升高硝酸银浸渍液浓度，光催化性能又降低.实验通过X-射线衍射（XRD）和 透射电镜（TEM）对载银TiO2/沸石催化剂的表征,结果表明,金属银对电子的捕获使得电子-空穴对有效分离， 从而使银 改性光催化剂的活性提高.     

Highly Efficient Removal of Organic Dyes by Novel As-synthesized AgBr/montmorillonite Composite

A facile deposition method has been developed for large-scale synthesis of visible-light-driven AgBr/montmorillonite composite catalyst for the first time. The as-synthesized samples were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR), transmission electron microscopy(TEM), UV-vis diffuse reflectance spectroscopy(UV-vis DRS) and Brunauer-Emmett-Teller(BET) surface area analysis, respectively. Through the combined action of adsorption and photodegradation, the as-prepared AgBr/montmorillonite composite exhibited a higher removal efficiency for rhodamine B(RhB) than that of Na-montmorillonite and AgBr. For the methyl orange(MO) removal, the AgBr/montmorillonite composite possessed a superior photocatalytic performance compared with Namontmorillonite and AgBr. The enhanced photocatalytic activity of AgBr/montmorillonite composite can be attributed to the effective separation of the electron-hole pairs. In AgBr/montmorillonite suspension, the superoxide radicals are the main reactive oxygen species for dye degradation under visible light illumination.     

利用含葡萄糖废水光催化制氢

研究了葡萄糖为电子给体在Pt/TiO2上光催化生成氢的反应.葡萄糖明显提高了制氢反应效率,反应5 h内,反应生成氢的量与反应时间成线性关系;葡萄糖初始浓度对生成氢反应速率的影响符合Langmu ir关系式;考察了无机离子对光催化反应的影响;用循环伏安法对光催化反应进行监测,发现降解过程中生成了葡萄糖酸.讨论了可能的反应机理.     

A Fundamental DFT Study of Anatase(TiO_2) Doped with 3d Transition Metals for High Photocatalytic Activities

Anatase(TiO_2) has been widely used in photocatalysis. However, it can only absorb near-ultraviolet light with a wavelength below approximately 388 nm due to a wide band gap. Therefore a modification should be made for anatase to increase its capability in utilizing more abundant visible light. We investigated the doped anatase with the most promising 3d transition metal elements, and the results showed that the visible light absorption intensity was increased significantly due to the reduced band gap and the cavitation effects. As compared to other 3d transition metals, Cu was found to be the most effective one in improving anatase photocatalytic effects. In addition, greater Cu concentration doped in the anatase increased the photocatalysis effects but reduced the anatase stability, therefore, an optimized Cu concentration should be considered to optimize the anatase photocatalysis activity.     

Photocatalytic Degradation of Methyl Thionine Chloride in Aqueous Solution over Nanometer （ CdS/TiO2 ）/MCM-41

（ CdS/ TiO2 ）/ MCM-41 loaded nanometer photocatalyst was prepared by the sol-gel method and dipping process, the photocatalytic degradation of methyl thionine chloride in water was investigated by using the photocatalyst. The experimental results show that the optimum concentration of CdS over TiO2 was 3% （ molar ratio ）, the photocatalytic activity was enhanced when making TiO2 the anatase ptase with a rise of the roasting temperature, and the carrier, mesoporous molecular sieve MCM-41, was beneficial to improving the photocatalytic activity of TiO2 for photocatalytic degradation of methyl thionine chloride. The morphology and the crystalline phase of the photocatalyst were discussed by means of XRD and SEM techniques, and the reaction mechanism of catalytic properties was also discussed.