掺杂铁离子和铜离子的TiO2光催化剂的研究

利用钛酸正四丁酯水解制备了几种不同浓度的TiO2胶体,在降解甲基橙后发现,R（乙醇与水物质的量比）值为1／50的0．01mol／L TiO2胶体降解效果最好。在不同的pH值、反应温度、搅拌速度下制备了同时掺杂铁离子和铜离子的R值为1／50的0．01mol／L TiO2胶体,通过光降解甲基橙,发现pH值、反应温度、搅拌速度和掺杂离子浓度对TiO2胶体的形态、掺杂效果和光催化活性均有影响。对比纯TiO2胶体的光降解甲基橙效果发现,掺杂铁离子和铜离子的TiO2光催化剂在pH值2．0、低搅拌速度、室温情况下,具有更好的光催化活性。     

Low temperature preparation and characterization of nanospherical anatase TiO2 and its photocatalytic activity on Congo red degradation under sunlight

Nanospherical titanium oxide with anatase structure was obtained at low temperature and normal pressure using a simple method of preparation. The dilute titanium (III) chloride solution was stirred at room temperature for several hours, and then ammonium hydroxide with hydrogen peroxide was added. A yellow gel TiO₂·xH₂O was obtained with nanodot shape and amorphous structure. Heated at 300 °C, it crystallized to pure anatase structure with nanospherical shape. The anatase particles prepared show good adsorption and photodegradation of Congo red solution under the sunlight. Materials were characterized by powder X-ray diffraction, thermal analysis, transmission electron microscope and UV spectroscopy.     

分子自组装制备的掺杂WO3的TiO2光催化薄膜的表征

利用分子自组装技术在载波片上制备了锐钛相TiO2及WO3掺杂的TiO2薄膜。利用原子力显微镜(AFM)和UV-VIS-NIR分光光度计对薄膜进行了表征。利用对罗丹明B的降解评价了所制备薄膜的光催化活性。结果表明：当W／Ti=2at％时，TiO2薄膜的光催化活性得到提高。     

聚苯胺插层三氧化钼复合光催化剂的制备及性能

以苯胺柱撑的三氧化钼有机-无机杂化体为反应前躯体,在空气气氛下于120 ℃进行氧化聚合,制备了一种聚苯胺插层MoO₃ 复合材料。以罗丹明B(RhB)为目标降解物,以MoO₃ 复合材料为光催化剂,考察了其催化性能,并研究了光照时间、催化剂质量浓度和pH 与光催化降解效率的关系。结果表明,在pH 为1~4、催化剂的质量浓度为0.30~0.40g/L、光照时间2.0h的条件下,MoO₃/PANI复合材料对罗丹明B具有良好的光降解效果,降解率最高可达98.00%。     

柠檬酸改性Bi2O3光催化材料性能的研究

以Bi（NO3）3溶液为原料,浓氨水为矿化剂,在柠檬酸掺杂量为1％-3％（质量分数）的条件下制备了纳米Bi2O3粉体。以样品对水中罗丹明B的光催化降解性能为评价指标,对样品的光催化性能进行了评价。研究结果表明：采用水热合成法制备的柠檬酸改性纳米Bi2O3粉体光催化降解水中罗丹明B的反应为表观零级反应。当柠檬酸的掺杂量为1．5％时,样品的光催化性能最优,继续增加掺杂量,样品光催化性能有所下降。紫外光条件下样品的光催化性能优于日光条件下。     

纳米ZnO的制备及其光催化降解酸性红B

以Zn（acac）2·H2O为单源前驱体,用水热法成功地制备了纳米ZnO,利用X-射线衍射、扫描电子显微镜、透射电子显微镜等手段对样品进行了表征。对自制的纳米ZnO进行了光催化活性研究,结果表明：纳米ZnO对200～380nm波长范围的光和在可见光范围内都有较强的吸收作用。利用纳米ZnO作为光催化剂对有机染料溶液进行了降解实验,发现在太阳光照射3h后,对酸性红B的降解率可达到100%。     

Single-crystalline heterostructure of ZnO nanowire arrays on large Ag microplates and its photocatalytic activity

This paper presents experimentally a photocatalytic heterogeneous structure of high-density ZnO nanowire (NW) arrays grown on large Ag microplates. First, the dense single-crystalline ZnO NW fabricated using an economical hydrothermal method possess a great reactive surface area because of their high surface-to-volume ratio. In addition, the large Ag microplates synthesized using a simple and competitive growth method serve as an electron reservoir. The heterojunction between ZnO NW and Ag microplates forms a Schottky contact to separate the electrons from the photogenerated excitons in ZnO NW, prolonging the lifetime of excitons and enhancing their photocatalytic capability. The photodegradation experiment employs the methylene blue aqueous solution to reveal a kinetic rate constant of up to 6.60 × 10^?3 min^?1 at a low concentration of the ZnO/Ag heterogeneous structure on the ppm scale, and indicates an outstanding figure of merit of 1.02 × 10^?2 compared with previously reported ZnO/Ag heterogeneous structures.     

Carbon-based TiO2-x heterostructure nanocomposites for enhanced photocatalytic degradation of dye molecules

Application of brown titanium dioxide (TiO_2-x) and its modified composite forms in the photocatalytic decomposition of organic pollutants in the environment is a promising way to provide solutions for environmental redemption. Herein, we report the synthesis of effective and stable TiO_2-x nanoparticles with g-C₃N₄, RGO, and multiwalled carbon nanotubes (CNTs) using a simple hydrothermal method. Among all the as-synthesized samples, excellent photocatalytic degradation activity was observed for RGO-TiO_2-x nanocomposite with high rate constants of 0.075 min^?1_, 0.083 min^?1 and 0.093 min^?1 for methylene blue, rhodamine-B, and rosebengal dyes under UV–Visible light irradiation, respectively. The altered bandgap (1.8 eV) and the large surface area of RGO-TiO_2-x nanocomposite impacts on both absorption of visible light and efficiency of photogenerated charge electron (e^?)/hole (h⁺) pair separation. This resulted in enhanced photocatalytic property of carbon-based TiO_2-x nanocomposites. A systematic study on the influence of different carbon nanostructures on the photocatalytic activity of brown TiO_2-x is carried out.     

Synthesis of a Fe3O4-rGO-ZnO-catalyzed photo-Fenton system with enhanced photocatalytic performance

In this work, we designed a magnetically-separable Fe₃O₄-rGO-ZnO ternary catalyst, ZnO anchored on the surface of reduced graphene oxide (rGO)-wrapped Fe₃O₄ magnetic nanoparticles, where rGO, as an effective interlayer, can enhance the synergistic effect between ZnO and Fe₃O₄. The effects of three operational parameters, namely irradiation time, hydrogen peroxide dosage, and the catalyst dosage, on the photo-Fenton degradation of methylene blue and methyl orange were investigated. The results showed that the Fe₃O₄-rGO-ZnO had great potential for the destruction of organic compounds from wastewater using the Fenton chemical oxidation method at neutral pH. Repeatability of the photocatalytic activity after 5 cycles showed only a tiny drop in the catalytic efficiency.     

Facile fabrication of ordered assembled TiO2/g-C3N4 nanosheets with enhanced photocatalytic activity

A series of assembled porous TiO₂/g-C₃N₄ (TC) powders composed of spherical nanoparticles were synthesized by controlling the molar ratio of urea to tetrabutyl titanate (TBOT) in a facile hydrothermal process. A nanosheets-constructed hierarchical structure was obtained at the molar ratio of urea to TBOT of 10:1, which possessed uniform mesopores with bimodal distribution (0.5–1.5 nm and 2–20 nm) and interconnected macropores between TC nanosheets. The specific surface area achieved 98.4 m² g^?1. X-ray diffraction (XRD) patterns and high resolution transmission electron microscope (HRTEM) analysis proved that the nanosheets are made of overlapping TC nanocomposite. Photoluminescence (PL) spectra results illustrated that a well-defined hierarchical porous structure is particularly desired for the low recombination rate of carriers. Further, the TC-decorated carbon fiber (CF) cloth was obtained based on the nanosheets assembled hierarchical structure, which showed more outstanding photocatalytic behavior with high degradation capability for Rhodamine B (RhB) (99.9%) and tetracycline hydrochloride (89.8%) at 60 min by 500 W Xe lamp irradiation. After five consecutive cycles, the degradation efficiencies of TC/CF cloth for both RhB and tetracycline hydrochloride all remained above 90% of the initial value.