WO_3纳米网格的制备及其光催化性能研究

WO3是一种带隙约为2.6eV过渡金属半导体,可见光便能激发其光催化活性,这极大地提高了太阳光的利用率,但纯WO3纳米材料催化活性较低,针对这一难题,国内外研究者大多采取对其表面改性来提高它的光催化性能,对WO3本身进行原位研究的报道极少。实验致力于改进WO3纳米材料的形貌结构来拓展其光催化性能。分别采取CaCl2和Na2SO4为诱导盐,Na2WO4为W源,在一定的pH值条件下水热制备WO3纳米网格和纳米线;并研究了这两种不同形貌结构的WO3纳米材料的光催化活性。研究表明,WO3网格立体网格结构具有更好的催化性能。实验发现WO3网格独特的层状结构能减少太阳光的逃逸,增强对光的吸收;网格结构具有更大的比表面积,能增加光催化过程中催化剂与有机物的反应活性点;这两点可能是立体网格结构WO3促进光催化反应的重要原因。     

TiO_2-Pt/CuS光电材料的制备及性能研究

采用电化学沉积Pt和化学沉积CuS的方法对TiO2纳米管阵列电极进行复合修饰,获得了二元TiO2-Pt和三元TiO2-Pt/CuS纳米结构体系。用SEM和TEM-EDS对催化剂进行了表征,并用水和有机物作为目标物,评价所制备的催化剂的光电活性。结果表明,TiO2在电化学和化学沉积后都能够保持原有形貌;Pt在纳米管内和阵列表面都有沉积,部分CuS与Pt形成混相复合状态。水的分解和有机物的降解的结果表明,所制备的光电材料的光电活性顺序为TiO2-Pt/CuSTiO2-PtTiO2。     

CdS/Zn-Fe LDO复合材料光催化降解孔雀石绿

采用沉淀法将CdS与锌铁层状双金属氢氧化物（Zn-Fe LDH）复合，高温煅烧后得到CdS/ZnO-ZnFe2O4复合材料（CdS/Zn-Fe LDO）。利用XRD、SEM、UV-vis DRS及PL对复合材料的结构、形貌、光学性能进行了表征。研究了该复合材料在可见光下对孔雀石绿的光降解，结果表明：CdS/Zn-Fe LDO复合材料对孔雀石绿的光催化降解能力高于CdS或Zn-Fe LDO，其中，m(CdS) : m(Zn-Fe LDH)=1 : 1配比制备的CdS/Zn-Fe LDO（1:1）光催化活性最大。光照20 min，20 mg CdS/Zn-Fe LDO（1:1）对20 mg/L孔雀石绿的光降解率为96.6%。此外，该复合材料还可降解罗丹明B、亚甲基蓝、甲基橙、结晶紫等染料且光降解反应符合一级反应动力学。     

单晶SiC的电助光催化抛光及去除机理

为满足电子半导体等领域对SiC超光滑、无损伤和材料高效去除的要求，提出了电助光催化抛光SiC的新方法。研究了光催化剂种类及其pH值对抛光液氧化性和抛光效果的影响，讨论了材料的去除机理。结果表明：以p25型TiO2为光催化剂配制抛光液所获得的最大氧化还原电位为633.11 mV，材料去除率为1.18 μm/h，表面粗糙度Ra=0.218 nm；抛光后SiC表面氧化产物中，Si-C-O、Si-O和Si4C4O4的含量明显增加，SiC表面被氧化并被机械去除是主要的材料去除方式。     

Photocatalytic Synthesis of p-Anisaldehyde in a Mini Slurry-Bubble Reactor under Solar Light Irradiation

Dense photocatalyst slurry was employed for the synthesis of p-anisaldehyde under solar light irradiation. An Fe-modified rutile TiO ₂ (Fe-TiO _2, 34.5 m ²/g) photocatalyst was used as a visible-light-responsive photocatalyst. A conventional TiO ₂ (P25, 35 m ²/g) photocatalyst was also examined as a reference catalyst. XRD patterns and diffuse reflectance spectra showed that Fe-TiO ₂ consists of 100 % rutile phase and absorbs more visible light compared to P25, respectively. The catalyst powder was suspended in an ethyl acetate solution of p-methoxytoluene in the mini-reactor, with oxygen bubbling, under a solar simulator, visible light, and UV LEDs. p-anisaldehyde, as a reaction product, was analyzed by sampling using gas-chromatograph. Regardless of the light source, Fe-TiO ₂ always outperformed P25 in terms of both generation rates (GR) of p-anisaldehyde and energy requirements (ER). It was demonstrated that the highly dense Fe-TiO ₂ slurry was efficient for the synthesis under solar light owing to the small size of the reactor. The small amount of Pt and ZrO ₂ cocatalysts significantly enhanced the GR under solar light. By adopting a visible light responsive Fe-TiO ₂ photocatalyst, the mini slurry-bubble reactor under solar light achieved a high GR per catalyst mass (CM), which is one to two orders higher than that reported by most previous studies with high-power lamps.     

Photocatalytic conversion of ethane: status and perspective

Ethane (C₂H₆) is a main component of natural gas and a notable contributor to photochemical pollution and ozone production in the atmosphere. It is important to convert ethane to useful chemicals. The photocatalytic conversion of ethane is promising but challenging. As the first review article in this area, we summarize the recent important progresses in photocatalytic ethane conversion, with an emphasis on (1) homogeneously functionalization and (2) heterogeneously partial oxidation of ethane. Furthermore, the challenges and future directions are provided for the photocatalytic conversion of ethane.     

Preparation and properties of visible light responsive g-C3N4/BiNbO4 photocatalysts for tinidazole decomposition

The g-C₃N₄/BiNbO₄ photocatalysts have been successfully fabricated by a facile ultrasound assisted impregnation route. The photocatalyst was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectra and Brunauer-Emmett-Teller techniques. The photocatalytic studies reveals that 40 wt% g-C₃N₄/BiNbO₄ photocatalyst exhibited significantly enhanced photocatalytic activity than BiNbO₄ and g-C₃N₄ photocatalysts toward degrading tinidazole under visible light irradiation. This excellent photocatalytic activity was revealed in terms of the extension of visible light response and efficient separation and transportation of the photogenerated electrons and holes due to coupling of g-C₃N₄ and BiNbO₄.     

Two-dimensional nanomaterials for photocatalytic water disinfection: recent progress and future challenges

Photocatalysis has received ever-growing attention as a promising alternative to traditional water treatment technologies for waterborne biohazard inactivation. Due to unique optical, electronic, physicochemical properties and feasibility of functional architecture assembly, two-dimensional (2D) nanomaterials have become important in developing novel photocatalysts. This review summarizes the recent progress in configuring nanostructures with 2D materials as building blocks for photocatalytic water disinfection. In this review, five categories of 2D nanomaterials, that is, graphene, graphitic carbon nitride, 2D metal oxides and metallates, metal oxyhalides and transition metal dichalcogenides, for photocatalytic pathogen inactivation are introduced. First, the synthesis process, nanostructure engineering and disinfection performance of 2D-based photocatalysts are reviewed in categories. In the following section, the bacteria destruction mechanism based on the generation and roles of reactive species (RSs) is presented. Moreover, the effects of the chemical characteristics of the water matrix on photocatalytic bactericidal performance are discussed. Finally, the challenges regarding the development and application of 2D-based photocatalysts for highly efficient water sterilization are highlighted. © 2018 Society of Chemical Industry