Solid-state synthesis and fluorescence properties of micron Bi2MoO6:Eu3+/C3N4 composite phosphors

The red emitting composite phosphors Bi₂MoO₆:Eu³⁺/C₃N₄ were prepared via a solid-state method and characterized by different techniques like XRD, SEM, FT-IR, Raman, UV-vis DRS and PL. The effects of reaction temperature and C₃N₄ amount on the structure and optical properties of Bi₂MoO₆ were studied in detail. The powder X-ray diffraction patterns showed that the crystal phase structure changed with the increase of temperature. Also, the introduction of C₃N₄ had a significant impact on photoluminescence properties, which provides a universal strategy for phosphors to improve luminescence performance.     

Ultrasound assisted deposition of highly stable self-assembled Bi2MoO6 nanoplates with selective crystal facet engineering as photoanode

The use of crystal facets of photocatalysts is well known as a promising strategy for the design of new photocatalysts with interesting physicochemical features for energy production applications. In this work, Bi₂MoO₆ thin films were synthesized by two methods, electrodeposition and sonoelectrodeposition. Preferential growth orientation depended on synthesis method. Results suggested that sonoelectrodeposition led to dominate the crystal facet {1 0 0} growth with self-assembled nanoplate morphologies while growth orientation in the {0 1 0} facet was dominant in electrodeposition in the absence of ultrasonic waves. As a highlight result, the {1 0 0} facet shows a smaller band gap, higher photocatalytic water splitting than the {0 1 0} facet. Efficient separation of charge pairs and long life time of photogenerated electrons was observed to be intrinsic features of the {1 0 0} facets. The higher charge transfer was confirmed by a higher photocurrent from linear sweep voltammetry and a smaller Nyquist radius arc. Ultrasound plays a key role in growth orientation and led to a production of homogeneous films with nanoplates which self-assembled together to form a flower-like structure. While in the absence of ultrasound the film has coral-like structure. Highly stable sonoelectrodeposited films exhibited incident photon-to-electron conversion efficiency (IPCE) of 22.4% at the specific wavelength of 500 nm. The sonoelectrodeposition method could act as a promising method for forming new films with specific crystal facet selection and developing as highly efficient photoanodes for PEC water splitting.     

网状钼酸铋的可见光催化活性

采用无助剂、无模板的水热法成功合成网状Bi₂MoO₆. pH值对这一形貌的形成起重要作用. 所制备的网状Bi₂MoO₆样品表现出优异的可见光催化活性,其光催化活性比固相法合成的块状Bi₂MoO₆样品高得多.     

FeTPP-Cr-TiO2微球的制备及其可见光催化性能

通过四苯基铁卟啉敏化Cr掺杂TiO₂微球成功合成了一种复合改性可见光催化剂FeTPP-Cr-TiO₂.利用XRD、FT-IR、SEM、XPS、UV-Vis和N₂吸附-脱附等温线等技术对其结构和形貌进行了表征.以亚甲基蓝为目标降解物,在150 W氙灯的辐照下,考察了其可见光催化活性.结果表明FeTPP-Cr-TiO₂呈锐钛矿相,表面积为74.7 m²/g.与Cr-TiO₂和FeTPP-TiO₂相比,FeTPP-Cr-TiO₂表现出很好的可见光降解性能.以三种喹诺酮类抗生素（洛美沙星、诺氟沙星和氧氟沙星）为实验对象,考察了FeTPP-Cr-TiO₂降解水体中抗生素的可行性,对三种抗生素均有很高的降解率,降解过程符合一级动力学模型,反应动力学常数分别为3.02×10^-2、2.81×10^-2和3.86×10^-2min^-1,半衰期为22.9、24.6及17.9 min.     

掺Fe3+A-TiO2粉末的制备及其可见光催化降解碱性品红

以硫酸钛为原料用水热法制备了掺Fe3+TiO2粉末,用SEM测定了样品的形貌和晶型,研究了以自制的掺Fe3+ A-TiO2对碱性品红溶液的光催化降解作用.结果表明:所制备的TiO2为锐铁矿型TiO2(A-TiO2).可见光照射下,用自制的掺Fe3+A-TiO2降解碱性品红溶液的最佳条件是:2mg·L-1的碱性品红溶液中...     

Synthesis and phonon properties of nanosized Aurivillius phase of Bi2MoO6

Nanosized crystallites Bi₂MoO₆ of a platelet shape were synthesized by a mild hydrothermal crystallization process. The effect of particle size on the structure and properties of Bi₂MoO₆ was studied by X‐ray diffraction, transmission electron microscopy, as well as Raman and infrared (IR) spectroscopies. Moreover, temperature‐dependent Raman spectra were collected for bulk and nanocrystalline Bi₂MoO₆. These studies showed that the thickness of the smallest crystallites is about 8–11 nm. Raman and IR studies have revealed that the damping and the intensity of Raman and IR bands are significantly modified with decreasing particle size and temperature. Moreover, some bands experience significant shifts both towards lower and higher wavenumbers. The obtained results indicate that, similar to the isostructural Bi₂WO₆, the orthorhombic distortion decreases with decreasing particle size. However, the structure of nanocrystalline Bi₂MoO₆ remains orthorhombic and noncentrosymmetric, and the structural changes are not the same as those observed in Bi₂WO₆. Copyright © 2010 John Wiley & Sons, Ltd.     

可见光响应SO2－4／Ce-TiO2的光谱特征及催化性能

采用溶胶‐凝胶法制备了Ce掺杂 T iO2,经 H2 SO4处理得到酸化Ce掺杂 T iO2。利用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、吡啶吸附红外光谱（Py‐FTIR）、紫外‐可见光漫反射光谱（UV‐Vis）及X射线光电子能谱（XPS）技术对样品的性质进行了表征,以罗丹明B（RhB）在样品上的可见光催化降解为模型反应,评价了所制备样品的光催化性能。XRD测试结果表明,铈掺杂使 TiO2产生晶格缺陷、粒径减小,有利于光生电荷的转移,继而提高催化剂的活性;FTIR谱图说明SO2－4以桥式双齿配位吸附形式存在;Py‐FTIR谱图显示,酸化铈掺杂TiO2样品表面同时存在Br?nsted和Lewis酸位,但以Lewis酸为主。Lewis酸中心的缺电子性质有利于样品表面的光生电子与光生空穴分离,从而改善催化剂的活性;UV‐Vis结果表明,Ce掺杂减小了TiO2的带隙能,引入的杂能级能够捕获导带上的光生电子和价带上的光生空穴,降低光生电子‐空穴对的复合几率;同时还可以使能量较小的光子激发杂能级上捕获的电子,拓宽光响应范围;XPS分析表明SO2－4／Ce‐TiO2样品上同时存在Ce3＋／Ce4＋的混合价态,Ce3＋／Ce4＋氧化‐还原转换有助于TiO2受光激发后产生的光生电子和空穴的分离,从而提高光量子效率。酸化Ce掺杂TiO2对RhB的可见光催化降解反应有很好的活性,实验结果证明,H2 SO4酸化和Ce掺杂的协同作用改善了样品的可见光响应,促进了其可见光催化反应活性。     

Bi2MoO6 nanofilms on the stainless steel mesh by PS-PED method: Photocatalytic degradation of diclofenac sodium as a pharmaceutical pollutant

For the first time, Bi₂MoO₆ nanofilms were successfully synthesized by simultaneous pulse sonication-pulse electrodeposition (PS-PED) on the stainless steel mesh surface. Bismuth molybdate films were formed under various combinations of electrodeposition and sonication (sono-electrodeposition) in continuous and pulse modes. Porous Bi₂MoO₆ films synthesized by PS-PED method and showed the highest efficiency in photocatalytic degradation in comparison with other films. Bi₂MoO₆ film obtained from PS-PED had a thickness of 13.78 nm while, the thickness for the electrodeposition method was 39.52 nm. The high photocatalytic efficiency is attributed to the high surface roughness and low thickness of film synthesized by PS-PED method. Indeed, ultrasound played a key role in the synthesis of films with high surface roughness. On the other hand, shock waves and micro-jets could be dissolved diffusion problems and reduced the dendrite like structures in deposition process. Simultaneous application of pulse modes for both combined methods led to more growth of crystallographic planes. This is due to reaction of ions on the surface in interval relaxation times and produce more nuclei for growth. In order to obtain a high efficiency, response surface methodology was used for optimization of effective variable parameters (t_on, t_off and sonication amplitude) in film preparation.     

Fabrication and efficient visible light-induced photocatalytic activity of Bi2MoO6/BiPO4 composite

Novel Bi₂MoO₆/BiPO₄ composites with heterojunction structure were fabricated by a one-step hydrothermal method. The photocatalytic properties of Bi₂MoO₆/BiPO₄ composites were evaluated by photocatalytic degradation of rhodamine B (Rh B) under visible light irradiation (λ>420 nm). The results showed that Bi₂MoO₆/BiPO₄ photocatalysts showed much higher photocatalytic activity for the Rh B degradation than the pure BiPO₄ and Bi₂MoO₆ under visible light. The best photocatalytic performance of Bi₂MoO₆/BiPO₄ with about 98.0% Rh B degradation located at molar ratio of 2:1 under visible light illumination for 30 min. The enhanced photocatalytic activity could be mainly ascribed to the formation of heterojunction interface in Bi₂MoO₆/BiPO₄ composites, which is beneficial to the transfer and separation of photogenerated electron–hole pairs, as well as the strong visible light absorption resulting from the sensitization role of Bi₂MoO₆ to BiPO₄. It was also observed that the photodegradation of Rh B is chiefly attributed to the oxidation action of the generated O₂⁻ radicals and the action of h_vb⁺ through direct hole oxidation process.     

Cucurbit[n]urils/CdS-MoS2的表征及可见光催化性能

为了降低CdS光生电子-空穴的复合对其光催化性能的影响,利用窄带隙半导体MoS₂和有机大分子瓜环(cucurbit[n]uril,Q[n])对CdS进行改性研究. 本文采用水热法合成了Q[n]/CdS-MoS₂\\(n=6,7,8)复合光催化剂. 利用FT-IR、XRD、XPS、SEM、UV-Vis和PL等手段对产物结构、形貌和光学等性质进行表征,并考察Q[n]/CdS-MoS₂复合催化剂对次甲基蓝、罗丹明B和结晶紫溶液的催化降解性能. 结果表明,瓜环对CdS-MoS₂颗粒生长结晶起到了调控作用,Q[n]/CdS-MoS₂(n=6,7,8)形成了具有花瓣状叶片的花团,催化剂表面积增大,活性位点增加,禁帯宽度减小,电子-空穴对得到了更好的分离和迁移. Q[6]/CdS-MoS₂和Q[7]/CdS-MoS₂对亚甲基蓝具有良好的光催化活性,催化过程为羟基自由基原理.     

Preparation and Visible Light Photocatalytic Activity for Photocatalyst of Permeable Glass Membrane/TiO2 Doped with Co

The photocatalyst of permeable glass membrane/TiO2 doped with Co （permeable glass membrane/TiO2 doped with Co） is prepared by the sol-gel method. The morphology and phase of the samples are determined by the field emission scanning electron microscopy （FESEM） and x-ray diffraction experiment, respectively. The photo- catalytic results show that the photocatalyst is sensitive to the visible light and exhibits excellent photocatalytic activity of photodegradation methylene blue. The photocatalytic mechanism is also discussed.     

The effects of Gd3+ doping on the physical structure and photocatalytic performance of Bi2MoO6 nanoplate crystals

Gd³⁺ doped Bi₂MoO₆ nanoplate crystals were fabricated by solvothermal combined calcination method. The effects of Gd³⁺ doping with different concentrations on the texture, crystal and optical properties of Bi₂MoO₆ were investigated by N₂ physical adsorption, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet–visible diffuse reflection spectrum (UV–vis DRS), photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Under simulated solar light irradiation, the influences of Gd³⁺doping on photocatalytic activity of Bi₂MoO₆ were evaluated by photocatalytic degradation of Rhodamine B. The characterization results showed that with Gd³⁺ doping, a contraction of lattice and a decrease in crystallite size occurred. Meanwhile, an increase in surface area over Gd³⁺ doped Bi₂MoO₆ was observed. Moreover, Gd³⁺ doping could obviously enhance the visible light harvesting of Bi₂MoO₆ and promoted the separation of photogenerated electrons and holes. With optimum Gd³⁺(6 wt%) doping, Gd/Bi₂MoO₆ exhibited the best activity and stability in degradation of Rhodamine B.     

圆盘状Bi2WO6-BiPO4异质结的水热合成及光催化性能 (cited: 1)

采用水热法制备Bi₂WO₆-BiPO₄异质结光催化剂．利用模拟太阳光照射下的罗丹明B降解实验评价了Bi₂WO₆-BiPO₄复合物的光催化性能．结果表明,Bi₂WO₆-BiPO₄光催化活性比Bi₂WO₆和BiPO₄高得多．当Bi₂WO₆与BiPO₄的摩尔比为1:1时复合光催化剂对罗丹明B的降解率最高．Bi₂WO₆-BiPO₄催化活性增强主要归结为两者之间形成了有效的异质结结构,其内建电场能够促进光生载流子的分离．同时,Bi₂WO₆的加入增强了其对可见光的吸收．研究表明O₂· ^-和h⁺在光催化降解过程中是主要的活性物种