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.     

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.     

石墨烯／二氧化钛复合光催化剂的制备及可见光催化性能研究

以钛酸正丁酯为钛源,采用一种简单的原位水解技术制备了石墨烯／二氧化钛复合光催化剂．通过XRD、SEM、TEM、Raman、PL和UV-vis光谱仪等分析手段对产物进行了表征,并测试了该复合光催化剂在可见光区对染料罗丹明B的光催化降解性能．实验结果表明：制备的复合光催化剂主晶相为锐钛矿型二氧化钛,石墨烯表面富集的二氧化钛颗粒尺寸约为10-20nm左右,均匀弥散、形成一层致密的氧化钛膜层．样品降解罗丹明B测试结果表明,石墨烯与二氧化钛的复合,一方面使得二氧化钛光催化剂在可见光区的吸收大大增强,另外,石墨烯的存在能够促进二氧化钛半导体中电子和空穴的有效分离,并且在一定程度上提高了污染物在半导体表面的富集效率,从而使石墨烯／二氧化钛复合光催化剂对降解罗丹明B表现出良好的光催化活性．     

ZnO/CuO复合催化剂的制备及其光催化性能

通过煅烧法制备了ZnO/CuO复合光催化剂,采用紫外-可见光谱(UV-Vis)、伏安光电流、X射线衍射(XRD)、扫描电镜(SEM)以及荧光光谱(PL)等方法对其结构、表面形貌和光学特性进行了表征。结果显示,复合物为片状结构的ZnO、晶粒呈现花簇状堆积生长的CuO组成了花簇状结构,CuO的引入提高了材料的光吸收能力和光生载流子的分离效率。复合催化剂对活性艳蓝(KN-R)的光催化降解结果显示,400℃煅烧3h、铜锌摩尔比为2时,ZnO/CuO复合光催化剂的光催化氧化性能最好,在紫外光照射下降解率可达94%,在可见光照射下降解率为48.4%。     

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.     

Co2+离子掺杂对TiO2结构与光催化活性的影响

论文采用溶胶-凝胶法制备Co2+掺杂的TiO2纳米粉末,以苯酚为目标污染物研究了Co-TiO2在不同的光源（紫外、可见）下的光催化活性,并利用XRD、EFSEM、UV-DRS和XPS等手段分析Co-TiO2结构与光催化活性的关系。结果表明,一部分Co2+离子成功进入TiO2晶格,有助于金红石相向锐钛矿相转变;另一部分Co2+离子在催化剂表面生成Co3O4,可与TiO2形成p-n异质结,两种结构变化均增强了光催化活性,且催化剂光谱吸收范围拓展至可见光区域。当Co2+掺杂量为1.0%,焙烧温度为773K时,Co-TiO2比表面积约为28.4m2/g,锐钛矿含量达到70.6%,光催化活性最好。2小时内,在紫外和可见光下,Co-TiO2对苯酚的降解率分别为97.7%和52.3%,均优于纯TiO2。     

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。     

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.     

Optimization of the operating conditions in a TiO2/Fe3O4-SiO2 photocatalytic reactor for the treatment of industrial wastewater containing Procion Red MX-5B

According to the design principle of the central composite experimental,the method of response surface analysis with three factors and three levels was adopted based on one factor test.A second-order quadratic equation for photocatalysis of Procion Red MX-5B was built.Response surface and contour were graphed with the decoloration rate of Procion Red MX-5B as the response value.Based on the analysis of the response surface plots and their corresponding contour plots,effects of pH value,irradiation time and catalyst loading were explored.By using this new method,the optimum decoloration condition was obtained as follows:pH value,1.3;irradiation time,49.9 min;catalyst loading,0.57 g/L.In the optimization,R-Squared and Adj R-Squared correlation coefficients for quadratic model were evaluated quite satisfactorily as 0.9310 and 0.8620,respectively.Under the optimum conditions established,the performance of 99.47% for color removal was experimentally reached.It was found that all factors considered have an important effect on the decolorization efficiency of Procion Red MX-5B.By the ANOVA analysis and model confirmation the optimal solution obtained using RSM was experimentally validated and credible with preferable instructional ability for experiments.     

燃烧法制备铁酸镍复合氧化物及光催化研究

抗坏血酸为燃烧剂,燃烧法制备铁酸镍复合氧化物。XRD表征分析确定硝酸铁和硝酸镍的最佳物质 的量比,紫外-可见光谱仪分析得到铁酸镍复合氧化物的吸光性能,电镜分析出复合物的形貌。以亚甲基蓝(0.01 g/L,100mL)为降解目标,铁酸镍复合氧化物为催化剂,双氧水为氧化剂进行复合物的光催化研究。结果表明,催化 剂用量、酸度、双氧水用量、光催化时间等条件对光催化都有着重要影响。光催化最佳实验条件为催化剂质量 20mg、pH=6、双氧水体积为6mL。实验结果表明,硝酸镍、硝酸铁和抗坏血酸物质的量比为1∶2∶1时,复合氧化 物在紫外和可见光下均有光催化效果;硝酸镍、硝酸铁和抗坏血酸物质的量比为2∶1∶1和1∶3∶1时,复合氧化物 在紫外光下有光催化效果。     

Dy-TiO2-膨润土复合催化剂处理茜素红、碱性品红的研究

为了在光照条件下催化降解茜素红、碱性品红染料,以膨润土为载体,钛酸正四丁酯和镝盐为原料,采用溶胶-凝胶法制备镝掺杂TiO2膨润土复合光催化剂(DTB).利用XRD、SEM对DTB的结构和形貌进行表征,表征结果表明其具有很高的比表面积,存在明显的锐钛矿型TiO2晶型特征峰,DTB中膨润土的晶面间距由1.691 nm变为1.887 nm,增大0.196 nm.研究催化剂的用量、染料的初始浓度、光照时间、pH值等因素对茜素红、碱性品红染料脱色率的影响、降解机理和它的动力学方程.实验结果表明:pH=7时,用0.1 g DBT处理茜素红、碱性品红染料溶液,光照45 min,降解量分别达18.0 mg/g.、19.5 mg/g.相同条件下,改用太阳光源,茜素红、碱性品红的降解量也达到20 mg/g以上.催化剂重复利用2次,茜素红和碱性品红的脱色率达80％以上.DBT对茜素红、碱性品红染料的光催化降解均符合二级动力学方程.     

N-Fe共掺杂BiVO_4的制备及其光催化活性的研究

采用溶胶凝胶法制备了N和Fe共掺杂的Bi VO4可见光光催化剂,并用X射线衍射(XRD)、比表面积测试(BET)和紫外-可见漫反射谱(UV-Vis DRS)对其进行了表征.结果显示,N-Fe共掺杂对Bi VO4晶型没有产生影响,掺杂前后均为单斜晶系,但晶粒粒径有所减小,BET比表面积相对增大.由UV-Vis可知,N-Fe共掺杂的Bi VO4的吸光强度明显增强,禁带宽度变窄.以可见光降解甲基橙(MO)考察催化剂的光催化活性,N-Fe共掺杂的Bi VO4对MO的降解速率明显高于纯Bi VO4,证明N-Fe共掺杂产生的协同效应提高了Bi VO4在可见光照射下的光催化活性.     

金属配位化合物光催化降解罗丹明B

当今世界的水污染日益严重、水资源逐渐匮乏,因此开发出利用太阳光能降解水中有机污染物的催 化剂是当前研究的热点之一。以金属配位化合物为光催化剂,在可见光的照射下,研究了其对有机染料罗丹明B的 光催化降解作用。结果表明,当罗丹明B水溶液的浓度为1×10-5 mol/L、罗丹明B水溶液的体积为80mL、催化剂 质量为0.02g、反应温度为25℃、可见光功率为300W、照射时间为120min时,Co(en) 3Cl3 对罗丹明B的降解率为 87%,Ni(en) 3Cl2 对罗丹明B的降解率为2%,Ni(dien) 2Cl2 对罗丹明B的降解率为8%。因此,Co(en) 3Cl3 是性能 良好的光催化剂。     

草酸改进铁/铜微电解体系降解活性艳蓝KN-R

在铸铁上负载铜的铁/铜催化微电解体系中加入草酸后,质量浓度为100 mg/L活性艳蓝KN-R溶液迅速脱色,化学需氧量明显降低,改善了微电解体系对废水处理时间长、化学需氧量去除效果低等缺点.实验结果表明:在pH为3.28(加入草酸后)、草酸投加量为5 mg/L、催化剂投加量为10 g/L的条件下,对质量浓度为100 mg...     

PdO负载Cu3V2O8光催化剂的制备及其光催化性能研究

采用浸渍法制备了PdO负载Cu3V2O8复合光催化剂,利用XRD、SEM对催化剂进行表征,研究其物相和表面形貌特征。在20W紫外灯照射下,以甲基橙为光催化模型降解产物,研究Pd的负载量对Cu3V2O8光催化活性的影响,探讨了负载Pd对光催化活性影响的机制。实验表明,Pd的负载对Cu3V2O8光催化活性影响很大,当Pd负载量为2.3%时光催化效果达到最好,比纯Cu3V2O8光催化剂提高40%左右.     

Preparation of TiO2 photocatalyst loaded with V2O5 for O2 evolution

TiO₂ photocatalysts loaded with V₂O₅ were prepared via a modified hydrolysis process, and characterized by X-ray diffraction, transmission electron microscopy, Raman spectra and diffuse reflectance UV-Vis spectra measurements. The photocatalytic activity of V₂O₅/TiO₂ was investigated by employing splitting of water for O₂ evolution. The results indicate that V₂O₅ loading can pronouncedly improve the photocatalytic activity of TiO₂ with Fe³⁺ as an electron acceptor under UV or visible light irradiation. The optimum mass fraction of the loaded V₂O₅ is 8%, and the largest speed of O₂ evolution for 8%V₂O₅ (mass fraction) loaded TiO₂ catalyst is 118.2 μmol/(L·h) under UV irradiation, and 83.7 μmol/(L·h) under visible light irradiation.     

MnFe2O4/TiO2的制备及其类芬顿光催化性能

以溶胶⁃凝胶法成功制备了MnFe2O4/TiO2类芬顿（Fenton）光催化剂,通过XRD、SEM、UV⁃vis对材料的结构和形貌进行表征,并以亚甲基蓝（MB）为目标污染物,对其进行降解,考察了不同掺杂量（质量分数）的产物在可见光下的光催化性能。结果表明,在光源为300 W的碘钨灯、MnFe2O4掺杂量为2%、催化剂质量为60 mg、pH=11、H2O2浓度为8 mmol/L时,光照180 min后,MnFe2O4/TiO2的光催化类Fenton反应对MB的降解率高达96.8%。相同条件下与未掺杂的纯TiO2相比,MnFe2O4/TiO2在可见光下对MB的催化性能有了明显提升。     

活性炭负载TiO2光催化降解甲醛

研究了活性炭负载TiO2所制得的光催化剂(TiO2/AC)对空气中甲醛光催化降解效果,考察了光照时间、TiO2负载量、空气流量对甲醛光催化降解效率的影响,讨论了TiO2/AC对甲醛的吸附性能以及吸附一定量甲醛后对其光催化效果的影响.结果表明:在活性炭表面负载TiO2后,对甲醛仍具有很强的吸附能力;光催化剂在空气中对甲醛的光催化降解效率可达94.06%;吸附甲醛后,稳定状态下甲醛光催化降解效率和新制备催化剂基本相同;在保证每次镀膜(TiO2)厚度达到300 nm的条件下,一次镀膜光催化效率高于多次镀膜;随着空气流量的增加,甲醛光催化降解效率有所提高.     

La和Zn共掺杂改性纳米TiO_2光催化剂的制备及表征

采用沉淀法-水热法相结合的方法分别制备未掺杂、La3+与Zn2+单掺杂及共掺杂的Ti O2光催化剂。通过SEM、XRD和UV-vis DRS等对样品形貌、结构和光吸收进行了表征,并以甲基橙溶液为目标降解物考察了掺杂纳米Ti O2粉体的光吸收和光催化性能。结果表明,La3+与Zn2+共掺杂后样品在紫外和可见光区的吸收能力显著提高,光吸收发生明显红移,吸收边波长为446 nm;La3+、Zn2+掺杂降低了光生电子-空穴对的复合率,光催化活性明显提高,光照20 min后,La/Zn/Ti O2对甲基橙的降解率高达99%。     

Structural characteristics and photocatalytic activity of ambient pressure dried SiO<Subscript>2</Subscript>/TiO<Subscript>2</Subscript> aerogel composites by one-step solvent exchange/surface modification

An ambient pressure synthesis of SiO₂/TiO₂ binary aerogel was prepared through the low-cost precursors of titanium tetrachloride (TiCl₄) and sodium silicate (Na₂O·nSiO₂). After gelation, solvent exchange and surface modification were performed simultaneously and the modified gel was finally dried under ambient pressure. Microstructural analyses by transmission electron microscope (TEM) indicate that fabricated SiO₂/TiO₂ aerogel composite shows similar sponge-like nanostructure as silica aerogel, and the Brunauer–Emmett–Teller (BET) analysis shows that the specific surface area of the composite reaches 605 m²/g, and the average pore size is 9.7 nm. Such binary aerogel exhibits significant photocatalytic performance in this paper for treating model pollutant of methyl orange (MO), and the decolorizing efficiency of MO is detected as 84.9% after 210 mins exposure to UV light irradiation. Degraded gel suspends in the water so as to separate from solution for reuse, and after 4 times recycling, 70% degradation efficiency can be easily reached when composite catalyzed system is exposed for 210 mins under UV irradiation.