掺镁钛酸钡纳米棒的水热合成和光催化性能

用水热法制备掺镁钛酸钡(Ba1-xMgxTiO3(x=0,0.10,0.20,0.30,0.40),BMT)纳米粉体。运用X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、紫外可见漫反射光谱技术(DRS)等手段对样品进行了表征,并在可见光照射下于溶液中考察了其光催化降解甲基橙反应活性。结果表明,通过控制氢氧根浓度可以得到不同形貌的纳米粉体。基于不同条件下制备的样品的微结构分析,提出了这些不同形貌的形成机制。制备出的BMT材料的带隙能约为2.61 eV。光催化反应结果表明BMT的光催化活性比掺氮TiO2高得多。OH-浓度为8 mol·L-1时制备的BMT纳米棒光催化效率最高,经可见光照射360 min,浓度为0.01 mmol·L-1甲基橙溶液的降解率可达到93.0%,且循环使用4次后,其光催化活性并没有明显降低,表明BMT是一种稳定有效的可见光催化剂.     

层状、花形和棒状钛酸铋纳米结构的可控合成及光催化性能

通过可控水热法,制备出层状、花形和棒状钛酸铋(Bi4Ti3O12,BIT)纳米结构。通过X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)观测其结构和形貌特征。XRD图显示,所制备的样品为层状钙钛矿结构。FESEM结果表明,通过控制水热过程的反应参数可以得到不同形貌的纳米粉体。紫外-可见漫反射光谱(UV-Vis DRS)表明BIT样品的带隙能约为2.63～2.95 eV。利用可见光(λ>420 nm)照射下的甲基橙降解实验评价了BIT样品的光催化性能。结果表明,BIT的光催化活性比掺氮TiO2(N-TiO2)高得多。所制备的层状BIT纳米结构光催化效率最高,经可见光照射360 min,甲基橙溶液的降解率可达95.0%。同时还研究了结构和形貌对不同条件下制备的BIT样品光催化活性的影响。     

层状、花形和棒状钛酸铋纳米结构的可控合成及光催化性能

通过可控水热法,制备出层状、花形和棒状钛酸铋(Bi₄Ti₃O₁₂,BIT)纳米结构。通过X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)观测其结构和形貌特征。XRD图显示,所制备的样品为层状钙钛矿结构。FESEM结果表明,通过控制水热过程的反应参数可以得到不同形貌的纳米粉体。紫外-可见漫反射光谱(UV-VisDRS)表明BIT样品的带隙能约为2.63~2.95eV。利用可见光(λ>420nm)照射下的甲基橙降解实验评价了BIT样品的光催化性能。结果表明,BIT的光催化活性比掺氮TiO₂(N-TiO₂)高得多。所制备的层状BIT纳米结构光催化效率最高,经可见光照射360min,甲基橙溶液的降解率可达95.0%。同时还研究了结构和形貌对不同条件下制备的BIT样品光催化活性的影响。     

不同形貌Bi4Ti3O12粒子的可控合成及光催化性能

研究了用一步水热法制备的不同形貌的钛酸铋(Bi₄Ti₃O₁₂, BIT)粒子的光学和可见光催化性能, 并对其晶体结构和微观结构用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)等手段进行了表征. XRD结果表明, 所制备的BIT 样品为层状钙钛矿结构. FESEM结果表明, 通过控制水热过程的反应参数可以得到不同形貌的纳米粒子. 紫外-可见漫反射光谱(UV-Vis DRS)表明BIT 样品的带隙能约为2.88-2.93 eV. 利用可见光(λ>420 nm)照射下的甲基橙(MO)降解实验评价了BIT 样品的光催化性能. 结果表明, BIT 的光催化活性比掺氮TiO₂ (N-TiO₂)高得多. 研究了形貌对BIT 光催化性能的影响. 所制备的BIT纳米带光催化效率最高, 经可见光照射360 min, 甲基橙溶液的降解率可达到95.0%.     

控制胶体合成法制备掺铁TiO_2粉末及光催化降解甲基橙

分别采用控制胶体合成法和溶胶-凝胶法制备了2种不同掺铁方式的TiO2粉末,并用XRD、TEM、BET、UV-Vis、FS等技术对样品进行了表征。在紫外光照射下,以甲基橙溶液的光催化降解反应为探针,研究了掺Fe离子浓度、包覆的次数、不同掺杂方式对样品光催化活性的影响。结果表明,以均匀掺铁TiO2(铁含量大于0.02mol%)干凝胶粉末为载体,采用控制胶体合成法制备了具有P-N结型结构的非均匀掺铁TiO2粉末,其光催化活性较均匀掺杂TiO2粉末明显提高,并且随着包覆次数(≤3次)的增加而增强,以0.04mol%掺铁TiO2粉末包覆3次后制备的样品具有最佳光催化活性,其表观速率常数是未掺杂的TiO2粉末的5.32倍,是具有相同Fe含量的均匀掺杂TiO2粉末的4.58倍。     

自掺杂TiO_2纳米管:液相制备及光催化性能

采用水合肼(N2H4·H2O)作为还原剂,在液相环境中制备了自掺杂TiO2纳米管阵列(NTs)。利用FE-SEM、EDS、XPS、XRD、Raman、UV-Vis/NIR分光光度法以及半导体特性分析系统(Keithley 4200 SCS)分别对样品的形貌,晶体结构,光学特性以及电学性能进行了表征。结果表明:通过这种方法制备的自掺杂TiO2NTs在带隙中引入了大量的氧空位,创造了氧空位能级,从而提高了样品的电导率,有效提高光生电子-空穴对的产生、分离和传输。此外,由于氧空位的作用,使得TiO2NTs的带隙变窄,增强了可见光吸收能力,致使样品具有较高的光催化活性,并通过降解甲基橙溶液对样品的光催化活性进行评估。结果显示当光照150 min后,自掺杂TiO2NTs对甲基橙溶液的降解率达73%,并且这种催化剂便于回收和重复使用。     

Fe-Ni 共掺杂 ZnO 的制备及其光催化降解甲基橙活性

 采用溶液法制备了 Fe-Ni 共掺杂 ZnO 光催化剂, 并运用 X 射线衍射、扫描电镜和原子发射光谱等对催化剂进行了表征. 以甲基橙 (MO) 为模型污染物, 评价了样品的光催化活性, 考察了甲基橙初始浓度及其 pH 值, 以及催化剂用量等对光催化反应性能的影响. 结果表明, Fe-Ni 共掺杂降低了 ZnO 的结晶度, 并促进了晶粒的长大. 光催化降解反应表明, Fe-Ni 共掺杂显著提高了 ZnO 光催化降解甲基橙的活性, 当催化剂用量为 0.6 g/L, 经 120 min 紫外光照射时, 可使甲基橙溶液 (10 mg/L) 降解率达到 93.5%. 关键词：铁; 镍; 共掺杂; 氧化锌; 光催化; 甲基橙; 降解     

Bi3.25Sm0.75Ti3O12纳米线的水热合成及可见光催化性能

用一步水热法制备了直径约为40 nm的Bi3.25Sm0.75Ti3O12(BSmT)纳米线。BSmT纳米线为层状钙钛矿结构。紫外可见漫反射光谱表明,制备出的BSmT材料的带隙能约为2.67 eV。催化反应结果表明,BSmT的光催化活性比掺氮TiO2(N-TiO2)和纯相钛酸铋(Bi4Ti3O12,BIT)高得多,经可见光照射360 min,浓度为0.01 mmol.L-1甲基橙溶液的降解率可达到92.0%。BSmT光催化剂具有更高催化活性的原因是Sm3+离子掺杂拓展了BIT对可见光的吸收范围,同时抑制了BIT的光生电子-空穴的复合。并且BSmT光催化剂经循环使用4次后,其光催化活性并没有明显降低,表明BSmT是一种稳定有效的可见光催化剂。     

可见光驱动Ag3PO4催化降解罗丹明B和甲基橙

采用简易离子交换法制备可见光驱动Ag3PO4光催化剂.通过X射线衍射、场发射扫描电子显微镜、N2吸附-脱附、紫外-可见漫反射光谱及傅里叶变换红外光谱对所制备的Ag3PO4催化剂进行表征.结果表明,在可见光照射下,Ag3PO4催化剂对罗丹明B降解表现出优越的光催化活性,但对甲基橙的降解活性低,这归因于Ag3PO4催化剂对甲基橙分子吸附量低.可见光照Ag3PO4反应体系中,空穴和超氧自由基共同发挥作用导致罗丹明B和甲基橙光催化降解.在罗丹明B的协助作用下,Ag3PO4催化剂对甲基橙的可见光催化降解活性大大增强,这是由于罗丹明B的存在可产生更多的超氧自由基,从而使甲基橙进一步降解.     

Ag-AgBr/RGO光催化性能研究

以石墨烯为载体,通过化学沉积与光还原法制备了具有等离子体共振效应的Ag-AgBr/RGO可见光催化剂。采用XRD及UV-Vis吸收光谱对催化剂进行结构与性能表征,并考察其降解甲基橙溶液的光催化性能。研究结果表明,在可见光下照射60min,催化剂对10 mg·L-1甲基橙溶液的降解率达91%。由于表面金属的等离子体共振效应和石墨烯的协同作用,石墨烯为载体的催化剂的可见光催化活性比氧化铝为载体时高。     

Synthesis, property characterization and photocatalytic activity of the novel composite polymer polyaniline/Bi2SnTiO7

A novel polyaniline/Bi(2)SnTiO(7 )composite polymer was synthesized by chemical oxidation in-situ polymerization method and sol-gel method for the first time. The structural properties of novel polyaniline/Bi(2)SnTiO(7) have been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray spectrometry. The lattice parameter of Bi(2)SnTiO(7) was found to be a = 10.52582(8) ?. The photocatalytic degradation of methylene blue was realized under visible light irradiation with the novel polyaniline/Bi(2)SnTiO(7) as catalyst. The results showed that novel polyaniline/Bi(2)SnTiO(7 )possessed higher catalytic activity compared with Bi(2)InTaO(7) or pure TiO(2) or N-doped TiO(2) for photocatalytic degradation of methylene blue under visible light irradiation. The photocatalytic degradation of methylene blue with the novel polyaniline/Bi(2)SnTiO(7) or N-doped TiO(2) as catalyst followed first-order reaction kinetics, and the first-order rate constant was 0.01504 or 0.00333 min(-1). After visible light irradiation for 220 minutes with novel polyaniline/Bi(2)SnTiO(7 )as catalyst, complete removal and mineralization of methylene blue was observed. The reduction of the total organic carbon, the formation of inorganic products, SO(4)2- and NO(3-), and the evolution of CO(2) revealed the continuous mineralization of methylene blue during the photocatalytic process. The possible photocatalytic degradation pathway of methylene blue was obtained under visible light irradiation.     

Wavelength-sensitive photocatalytic degradation of methyl orange in aqueous suspension over iron(III)-doped TiO2 nanopowders under UV and visible light irradiation

Well-crystallized iron(III)-doped TiO2 nanopowders with controlled Fe3+ doping concentration and uniform dopant distribution, have been synthesized with plasma oxidative pyrolysis. The photocatalytic reactivity of the synthesized TiO2 nanopowders with a mean particle size of 50-70 nm was quantified in terms of the degradation rates of methyl orange (MO) in aqueous TiO2 suspension under UV (mainly 365 and 316 nm) and visible light irradiation (mainly 405 and 436 nm). The photodecomposition of MO over TiO2 nanopowders followed a distinct two-stage pseudo first order kinetics. Interestingly, the photocatalytic reactivity depends not only on the iron doping concentration but also on the wavelength of the irradiating light. Under UV irradiation, nominally undoped TiO2 had much higher reactivity than Fe3+ -doped TiO2, suggesting that Fe3+ doping (> 0.05 at. %) in TiO2 with a mean particle size of approximately 60 nm was detrimental to the photocatalytic decomposition of methyl orange. Whereas, under visible light irradiation, the Fe3+ -doped TiO2 with an intermediate iron doping concentration of approximately 1 at. % had the highest photocatalytic reactivity due to the narrowing of band gap so that it could effectively absorb the light with longer wavelength. A strategy for improving the photocatalytic reactivity of Fe3+ -doped TiO2 used in the visible light region is also proposed.     

Photocatalytic degradation of methyl orange over metalloporphyrins supported on TiO2 Degussa P25

The photocatalytic activity of meso-tetraphenylporphyrins with different metal centers (Fe, Co, Mn and Cu) adsorbed on TiO(2) (Degussa P25) surface has been investigated by carrying out the photodegradation of methyl orange (MO) under visible and ultraviolet light irradiation. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance UV (DRS-UV-vis) and infrared spectra. Copper porphyrin-sensitized TiO(2) photocatalyst (CuP-TiO(2)) showed excellent activity for the photodegradation of MO whether under visible or ultraviolet light irradiation. Natural Bond Orbital (NBO) charges analysis showed that methyl orange ion is adsorbed easier by CuP-TiO(2) catalyst due to the increase of induced interactions.     

异质结型AgI/AgBr/TiO2催化剂的制备及其光催化性能

首先以沉积-沉淀法制备AgBr/TiO₂复合催化剂,然后采用离子交换法制备出新型的异质结型AgI/AgBr/TiO₂光催化剂.利用XRD和UV-Vis对AgI/AgBr/TiO₂光催化剂进行了表征.以甲基橙为染料模型,在可见光条件下(500 W、λ>420 nm)研究了AgI的含量对AgI/AgBr/TiO₂催化活性的影响.结果表明,AgI拓展了催化剂的吸收光谱范围;AgI生成量为AgBr的5%时,AgI/AgBr/TiO₂的催化活性最高.AgI/AgBr异质结的形成有利于光生电子和空穴的分离,提高AgI/AgBr/TiO₂的催化活性.     

Ag/AgBr/TiO2 visible light photocatalyst for destruction of azodyes and bacteria

Ag/AgBr/TiO2 was prepared by the deposition-precipitation method and was found to be a novel visible light driven photocatalyst. The catalyst showed high efficiency for the degradation of nonbiodegradable azodyes and the killing of Escherichia coli under visible light irradiation (lambda>420 nm). The catalyst activity was maintained effectively after successive cyclic experiments under UV or visible light irradiation without the destruction of AgBr. On the basis of the characterization of X-ray diffraction, X-ray photoelectron spectroscopy, and Auger electron spectroscopy, the surface Ag species mainly exist as Ag0 in the structure of all samples before and after reaction, and Ag0 species scavenged hVB+ and then trapped eCB- in the process of photocatalytic reaction, inhibiting the decomposition of AgBr. The studies of ESR and H2O2 formation revealed that *OH and O2*- were formed in visible light irradiated aqueous Ag/AgBr/TiO2 suspension, while there was no reactive oxygen species in the visible light irradiated Ag0/TiO2 system. The results indicate that AgBr is the main photoactive species for the destruction of azodyes and bacteria under visible light. In addition, the bactericidal efficiency and killing mechanism of Ag/AgBr/TiO2 under visible light irradiation are illustrated and discussed.     

TiO_2/Fe-杭锦2~#土催化剂光催化降解废水中乙酸的研究

首先采用离子交换法制得Fe-杭锦2#土,以其为载体使用溶胶-凝胶法制备了TiO_2/Fe-杭锦2#土负载型光催化剂,并通过X射线粉末衍射(XRD)、氮气吸附脱附(N2-BET)、固体紫外可见漫反射(UV-Vis DRS)、X射线光电能谱(XPS)和扫描电子显微镜(SEM)分析等对催化剂进行了表征.以光催化降解乙酸为探针反应,考察了Ti的负载量、光源、光照时间、催化剂用量和反应温度等反应条件对催化剂催化性能的影响.实验结果表明,对于浓度为100 mg·L-1的乙酸溶液,选用氧化钛负载量为20%的光催化剂、300 W汞灯为光源、反应温度为50℃、反应时间为6 h、催化剂用量为50 g·L~(-1)时,对乙酸的光催化降解效果相对最优,降解率达到78.30%.     

乙酸修饰Ag/TiO2复合光催化剂的制备及协同催化性能

利用光化学还原法制备了Ag/TiO₂,然后通过乙酸浸渍制备了HAc-Ag/TiO₂复合光催化剂.利用X射线衍射（XRD）、透射电子显微镜（TEM）、傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）和紫外-可见漫反射光谱（UV-Vis DRS）等手段表征了催化剂的性质.以降解水溶液中的甲基橙（MO）为探针反应,考察了催化剂在可见光下的光催化性能.结果表明,乙酸对TiO₂的修饰在TiO₂禁带中产生了"带尾",使TiO₂的禁带宽度发生了显著的缩减;Ag纳米粒子和乙酸共同修饰的HAc-Ag/TiO₂样品具有更窄的禁带宽度和更正的价带顶位置;Ag和乙酸的协同作用使HAc-Ag/TiO₂具有良好的可见光催化活性：可见光照射2 h后,甲基橙在HAc-Ag/TiO₂上的降解率接近100%.     

溴化银/二氧化钛复合材料的可见光催化性能

将硝酸银的乙醇溶液与溶胶凝胶TiO2混合得到前驱体,随后经共沉淀-煅烧制备得到AgBr/TiO2复合材料;采用扫描电镜、X射线衍射仪、X射线光电子能谱仪分析了复合材料的形貌、晶体结构、Ag元素的价态,采用紫外-可见漫反射光谱仪测定了其光吸收性能;进而以甲基橙(MO)的可见光降解为探针反应测定了AgBr/TiO2复合材料的可见光催化性能.结果表明,当前驱体在不同温度下煅烧后,无定形TiO2颗粒逐渐增大,并逐渐转变为锐钛矿结构;担载的AgBr可明显拓展TiO2的可见光吸收范围;Ag物种主要以Ag+形式存在.当煅烧温度为300℃时,复合材料的光催化活性最高,MO的降解率在60min内达到90%以上;随着煅烧温度的增加,催化活性逐渐降低.     

氧缺陷型SnO2纳米颗粒可见光催化性能的研究

由简单的水热法合成了一种可高效降解有机染料的氧缺陷型Sn O2纳米颗粒新型光催化剂,用X射线衍射、透射电镜、高分辨透射电镜和紫外-可见分光光度计等手段对其结构及性能进行了表征。结果表明,所制备的催化剂的禁带宽度最小可达2.90e V,可实现对可见光的有效吸收利用,对甲基橙的降解反应具有很高的光催化活性。将该催化剂(1g/L)分散在10mg/L的甲基橙溶液中,可见光照射下,40min内甲基橙的降解率达99%以上。由于该催化剂具有合成方法简单、高效、成本低和反应条件温和等特点,为有效解决有机染料对环境的污染问题提供了一条新的途径。