Chiral induction enhanced photocatalytic degradation of methyl orange by Ag@Ag3PO4 and the reaction mechanism

A novel chiral Ag@Ag₃PO₄-NaDC composite was synthesized by chiral induction. SEM, XRD, CD spectrum, FTIR, UV–vis and XPS were used to study the physical and chemical properties of the materials, and the photocatalytic oxidation ability was evaluated with methyl orange as the target pollutant. The results show that the introduction of chirality can obviously promote the light absorption ability, broaden the band gap, enhance the oxidation ability, promote the separation of electrons and holes, greatly enhance the plasma resonance effect of silver nanoparticles, and promote the synergistic effect between silver nanoparticles and silver phosphate. Compared with Ag@Ag₃PO₄, the catalytic degradation ability of chiral Ag@Ag₃PO₄-NaDC is improved by more than 60%. Therefore, the chiral Ag@Ag₃PO₄-NaDC composite exhibits excellent photocatalytic performance. In the degradation of methyl orange by Ag@Ag₃PO₄-NaDC, a large amount of ·O₂^- and h⁺ were formed on the surface, which was the main reason for the oxidation ability.     

Electrochemically assisted photocatalytic degradation of methyl orange using anodized titanium dioxide nanotubes

The TiO₂ nanotubes have demonstrated potential in the photoelectrocatalytic degradation of methyl orange dye (MO). TiO₂ nanotubes were prepared using anodization of titanium foils in phosphoric acid (PA) and ethylene glycol (EG) by mechanical stirring and ultrasonic method. The TiO₂ nanotubes prepared in EG under ultrasound followed by annealing in nitrogen atmosphere showed higher activity towards dye degradation as compared to the stirring method. Dye degradation shows improved activity under an external bias compared to degradation performed in the absence of an external bias. An increase in the external bias from +0.0 to +0.1 V versus calomel electrode (SCE) is sufficient to improve the degradation rates of MO from 22% to 57% within the first 10 min. At +0.1 V, a complete degradation of 40 μM MO is observed within 30 min. The addition of oxidants such as oxygen and hydrogen peroxide demonstrate improvement in the MO degradation.     

Zn掺杂TiO2的制备及其光催化降解甲基橙性能

采用沉淀法制备了不同掺杂量的Zn/TiO₂催化剂,以光催化降解甲基橙为探针反应,考察其光催化活性,并采用紫外漫反射和X射线衍射对其进行结构表征。研究结果表明,Zn的掺杂量对催化剂活性影响较大,最佳掺杂物质的量分数为1.5%;催化剂的紫外漫反射微分曲线的峰值变化与其活性变化一致,1.5%(物质的量分数) Zn/TiO2的微分峰值最大。X射线衍射分析表明,少量Zn高度分散在TiO₂晶格中。Zn掺杂物质的量分数1.5%时,添加2 g·L^-1的Zn/TiO₂催化剂,甲基橙降解的最佳条件：pH＝3,浓度15 mg·L^-1,降解率最高达98.6％。     

Multiple-metal-doped Fe3O4@Fe2O3 nanoparticles with enhanced photocatalytic performance for methyl orange degradation under UV/solar light irradiation

Waelz slag, which is a Fe-bearing hazardous waste, was applied as the raw material in the synthesis of M-Fe₃O₄@Fe₂O₃ (M = Al, Zn, Cu, and Mn) nanoparticles, which are potential photocatalysts. Through acidolysis, 97.23% of Fe and most of the valuable metals were extracted from this slag. Using sol-gel processes, designed Fe₃O₄@Fe₂O₃ nanoparticles doped with multiple elements were systematically synthesised and characterised using X-ray diffraction, field emission scanning electron microscopy, electron diffraction spectroscopy, transmission electron microscopy, and Brunauer–Emmett–Teller analysis. The photocatalytic activities of the synthesised particles and undoped Fe₂O₃ nanoparticles were compared through photocatalytic methyl orange degradation experiments under UV and simulated solar light. The results indicated that all of the slag-derived nanoparticles gave improved photocatalytic performances compared to the undoped sample, and the M-Fe₃O₄@Fe₂O₃ (M = Al, Zn, and Cu) sample exhibited the best photocatalytic activity. The enhancement can be attributed to grain refinement, doping, and the formation of a typical Fe₃O₄@Fe₂O₃ core-shell structure.     

WO_3/BiOBr复合催化剂的制备及可见光催化降解甲基橙

以Bi(NO_3)5·5H_2O、Na Br、H_2WO_4为原料,采用一步水热合成法合成不同n(W)∶n(Br)的WO_3/BiOBr复合催化剂,并通过SEM和TEM对催化剂进行表征分析。以甲基橙为探针污染物,考察前驱液pH、水热温度、水热时间和n(W)∶n(Br)对WO_3/BiOBr复合催化剂活性的影响。结果表明,在pH为10.2、100℃水热时间6 h合成n(W)∶n(Br)为0.02的WO_3/BiOBr复合催化剂活性最好,光照120 min后,对目标污染物的降解率达99.39%,较BiOBr催化剂(合成条件为原始pH值,100℃水热反应6 h)提高了30.85%。采用水热合成法制备的WO_3/BiOBr复合催化剂具有良好的可见光活性。     

活性炭纤维负载二氧化钛复合催化剂降解甲基橙性能研究

制备了活性炭纤维负载二氧化钛复合催化剂ACF/TiO2,并在紫外光下降解甲基橙以考察其催化活性。并在同等条件下,对未负载二氧化钛的活性炭纤维空白样品进行了对比实验;同时还考察了ACF/TiO2的循环使用寿命。结果表明,ACF/TiO2降解能力大于未负载的活性炭纤维,其降解能力是吸附性能和光催化性能的协同作用,并拥有较长的循环使用寿命。     

Tb掺杂介孔TiO_2/聚噻吩复合材料的制备及其可见光光催化性能研究

采用原位聚合法制备了一系列不同质量比m(Th)/m(Tb掺杂介孔TiO2)的复合光催化剂(其中Th为噻吩),采用XRD、FTIR、荧光光谱(PL)、场发射透射电镜(FETEM)和X射线光电子能谱(XPS)对复合光催化剂进行了表征。结果表明,复合粒子上的聚噻吩骨架中S原子与TiO2粒子间存在相互作用。以罗丹明B为模型降解物,研究了不同比例复合光催化剂在可见光下的光催化性能,其中m(Th)/m(Tb掺杂介孔TiO2)=1/10复合光催化剂光催化性能最好。在可见光照射下4 h,脱色率达到82.4%。这是由于Tb掺杂介孔TiO2与PTh(聚噻吩)之间的协同作用,拓宽了TiO2纳米粒子的光响应范围,提高了光生电子和空穴的分离效率,从而有效提高了其光催化性能。     

燃烧法制备纳米ZnO及光催化降解甲基橙的研究

分别以甘氨酸和柠檬酸为燃料,Zn（NO3）2为氧化剂,采用燃烧法制备纳米ZnO粉体并采用模拟太阳光进行甲基橙光催化降解研究。XRD和SEM表征样品表明,燃烧法能简单、快速制备纳米ZnO粉体。研究表明,燃烧剂和氧化剂的配比以及反应温度对制备的纳米ZnO降解甲基橙效果有较大影响。Zn（NO3）2与甘氨酸之比为0．2～0．5（物质的量比）,反应温度为5000C;Zn（NO3）2与柠檬酸之比为1．5,反应温度为600℃进行反应制备得到的纳米ZnO降解甲基橙效果较好。降解实验的结果表明,纳米ZnO能有效地光催化降解甲基橙染料。以柠檬酸为燃料制备的ZnO样品,在1h内对10mg·L^-1甲基橙溶液的降解率为90％。     

钨、氮共掺杂TiO2的制备及其光催化性能研究

为了更好的利用太阳能,以钛酸正丁酯为前驱体,硝酸铵和钨酸铵为掺杂离子给体,通过溶胶-凝胶法,室温下成功制备了纯TiO2和钨、氮掺杂和共掺杂的TiO2光催化剂.表征结果显示,共掺杂催化剂为锐钛矿型,外观呈球形,感光范围拓展到可见光区域.以甲基橙为降解物,氙灯为模拟太阳光光源,进行光催化降解实验,钨、氮共掺杂TiO2在光照...     

Facile fabrication of 3D interconnected porous boron doped polymeric g-C3N4 with enhanced visible light photocatalytic hydrogen evolution and dye contaminant elimination

Researchers have attempted to developing high-efficiency catalysts for photocatalytic hydrogen evolution and organic pollution elimination simultaneously to alleviate the issues of energy shortage and water pollution. In this work, we fabricated 3D interconnected porous boron doped polymeric g-C₃N₄ catalysts with efficient photocatalytic activity for hydrogen evolution and dye contaminant elimination under visible-light irradiation. The as-fabricated catalysts exhibited significantly enhanced hydrogen evolution (4.37 mmol g ^?1 h^?1) and RhB contaminant elimination (96.37%) activity. Based on characterization and photocatalytic tests, an enhanced mechanism of the superior photocatalytic performance was proposed: 3D interconnected porous structure and B-doping have a synergistic effect on the greatly improved photocatalytic activity. The 3D interconnected structures endowed g-C₃N₄ with a higher specific surface area and abundant active sites and improved the capacity of rapid absorption to facilitate the photocatalytic process. B doping provided enhanced visible-light absorption capacity and a narrowed bandgap and served as a “highway” for electron-hole pairs to facilitate migration and separation and suppress the combination of photogenerated carriers. Besides, the possible mechanism of enhanced photocatalytic performance was elucidated according to the results of characterization measurements and active species analysis.     

Preparation of cerium and nitrogen co-doped titania hollow spheres with enhanced visible light photocatalytic performance

N,Ce-codoped titania hollow spheres were prepared using carbon spheres as template and using N,Ce-codoped titania nanoparticles as building blocks. The N,Ce-codoped titania nanoparticles were synthesized at low temperature. The prepared hollow spheres were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and UV-Vis diffuse reflectance spectrum (DRS). The effect of N and Ce content on the physical structure and photocatalytic properties of the as-prepared hollow sphere samples was investigated. The mechanism of photocatalytic degradation of dyes under visible light irradiation was also discussed.     

TiO_2光催化甲基橙电化学阻抗法表征的研究

采用溶胶-凝胶法在Al2O3薄膜表面上制备了纳米TiO2光催化薄膜(TiO2/Al2O3),将此薄膜用于光催化降解甲基橙,采用电化学阻抗法分析了TiO2薄膜光电极在甲基橙溶液中暗态、光照、不同光强以及改变阳极偏压时的交流阻抗图谱。结果表明,电化学阻抗谱能够较好的反应光催化、光电催化降解甲基橙的实验过程;并且发现施加阳极偏压可提高薄膜的催化性能,发现0.4 V左右最佳。     

掺钇纳米二氧化钛光催化降解甲基橙的研究

采用金属钇掺杂改性,以钛酸四丁酯为主要原料,在室温下,利用溶胶-凝胶法制备了Y3+掺杂纳米TiO2光催化剂,通过X射线衍射分析(XRD)方法分析其改性机制;掺钇纳米TiO2光催化剂经太阳光照射后,用分光光度计测量光催化降解反应后甲基橙溶液浓度的变化,考察其光催化活性;研究了掺杂量和焙烧温度对光催化活性的影响。结果表明,Y3+掺杂能有效地抑制锐钛矿型TiO2向金红石型TiO2的转化,可使纳米TiO2的衍射峰宽化,粒径从80.5 nm降低到42.15 nm,掺杂量为1.2%,焙烧温度在400℃左右时,能够有效地提高TiO2光催化剂光催化活性。     

Structure,photocatalytic and antibacterial activity study of Meso porous Ni and S co-doped TiO_2 nano material under visible light irradiation

Undoped and Ni–S co-doped mesoporous TiO_2 nano materials were synthesized by using sol–gel method.The characteristic features of as prepared catalyst samples were investigated using various advanced spectroscopic and analytical techniques. The characterization results of the samples revealed that all the samples exhibited anatase phase(XRD), decreasing band gap(2.68 eV)(UV–Vis-DRS), small particle size(9.2 nm)(TEM), high surface area(142.156 m~2·g~(-1))(BET), particles with spherical shape and smooth morphology(SEM); there is a frequency shift observed for co-doped sample(FT-IR) and the elemental composition electronic states and position of the doped elements(Ni and S) in the TiO_2 lattice analyzed by XPS and EDX. These results supported the photocatalytic degradation of Bismarck Brown Red(BBR)achieved with in 110 min and also exhibited the antibacterial activity on Staphylococcus aureus(MTCC-3160), Pseudomonas fluorescence(MTCC-1688) under visible light irradiation.     

微波水热法制备稀土元素铒掺杂TiO_2光催化剂及光催化活性

采用微波水热法和溶胶-凝胶法制备稀土元素Er掺杂TiO_2光催化剂TiO_2-Er,以甲基橙溶液为模拟污染物,在微波辐射-紫外光照(MW-UV)和太阳光照条件下,考察TiO_2-Er光催化剂的光催化降解活性。分别用N_2吸附-脱附、ICP-AES和PL光谱分析对TiO_2-Er光催化剂进行结构测试和表征。结果表明,Er掺杂能显著提高TiO_2光催化剂光催化活性,微波水热法制备的TiO_2-Er光催化剂具有较高的光催化活性;微波水热法和溶胶-凝胶法制备的TiO_2-Er光催化剂微波辐射-紫外光照50 min,甲基橙降解率分别为100%和98.5%,太阳光照4 h,甲基橙降解率分别为99.0%和97.5%。微波水热法具有晶化时间短和元素掺杂均匀的优点,制备的TiO_2-Er光催化剂具有形貌均匀、孔径较大、孔分布均匀和比表面积较大等特点,且Er掺杂能抑制光生e~-/h~+复合,使光生e~-/h~+的分离效率得到提高,有利于光催化活性的提高。     

Simple synthesis of Cu2O/Na-bentonite composites and their excellent photocatalytic properties in treating methyl orange solution

Cu₂O/Na-bentonite (Cu₂O/NB) composites were firstly synthesized by a simple deposition method. The morphology and composition of the prepared catalysts were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, Brunauer–Emmett–Teller (BET) specific surface area. The results show that the Cu₂O microparticles can be immobilized on the surface of the NB. Visible-light photocatalytic properties of the Cu₂O/NB composites were evaluated using methyl orange (MO) as a model pollutant and the effects of various experimental factors on MO decolorization were investigated. Cu₂O/NB composites demonstrated a much higher photocatalytic activity than the pure Cu₂O particles under similar experimental conditions.     

Preparation of α-SnWO4 hierarchical spheres by Bi3+-doping and their enhanced photocatalytic activity under visible light

Bi-doped α-SnWO₄ porous spheres assembled by thin plates were prepared by a simple hydrothermal process without any template. The effects of Bi³⁺ ions on the microstructure and photocatalytic activity of α-SnWO₄ were investigated. The doping of Bi can induce a shape transformation from nanoplates of pure α-SnWO₄ to hierarchical spheres of Bi-doped samples. The photocatalytic activities of the as-prepared samples were evaluated by photocatalytic de-colorization of methyl orange (MO) under visible light irradiation. Bi-doped α-SnWO₄ samples exhibit better photocatalytic property than pure α-SnWO₄, and the optimal Bi-doping concentration is around 0.5 at%. The enhanced photocatalytic properties of Bi-doped α-SnWO₄ spheres can be ascribed to the porous hierarchical structure and the introduction of defects induced by Bi-doping, which improve visible-light absorption and allow the efficient charge separation of the photogenerated electron-hole pairs. Bi-doped α-SnWO₄ has a great potential in industrial water treatment due to its satisfactory recyclability and stability.     

液相法制备纳米TiO2的工艺及其光催化降解盐酸土霉素的研究

以钛酸丁酯为前驱体,分别采用水热沉淀法和溶胶-凝胶法制备纳米TiO2光催化剂,以氙灯为光源,盐酸土霉素为降解对象,考察2种方法下样品的光催化能力,并对水热沉淀法制备TiO2在不同煅烧温度、底物浓度、光照强度及催化剂用量条件下的光催化活性进行研究。结果表明,相比溶胶-凝胶法,水热沉淀法制备的TiO2的光催化反应速率常数较大,粒径小,分布均匀,分散性好,光吸收能力强。     

One-step fabrication of Ce–N-codoped TiO2 nano-particle and its enhanced visible light photocatalytic performance and mechanism

Ce, N codoped TiO₂ nano-particles were fabricated through sol–gel strategy in the absence of water. Results revealed that Ce was not implanted into the lattice of TiO₂ and existed as the forms of small cluster CeO₂ which uniformly diffused onto the surface or interstitial site of TiO₂, while N dopants were successfully incorporated into the structure of TiO₂ by substituting the lattice oxygen atoms and existed as the forms of N–Ti–O bonds, thereby resulting in the formation of impurity level above the valence band of TiO₂ and enhancement of visible photocatalytic (PC) performance. The enhanced visible PC mechanism was discussed.     

Synthesis of TiO2 nano-particles and their photocatalytic activity for formaldehyde and methyl orange degradation

TiO₂ nano-particles were synthesized by sol-gel technique and characterized by X-ray diffractometer (XRD) and transmission electron microscope (TEM). Their photocatalytic activities for formaldehyde (FA) and methyl orange (MO) degradation were tested using degradation rate (η) as an evaluation index. Based on the orthogonal test results, the optimal condition for TiO₂ preparation was obtained. Results showed that particle sizes were in the range of 10–40 nm, and that prepared TiO₂ had better photocatalytic activity than P25. A simplified model was developed to evaluate the apparent quantum efficiency (Φ _app) of this photocatalytic reaction system.