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以钛酸四丁酯为前躯物,采用溶胶-凝胶法制备了掺杂不同含量Pr的TiO2光催化剂,利用XRD,TG-DTA,AFM,UV-Vis,FTIR等手段对催化剂进行了表征。并通过酸性品红光催化降解实验对其光催化性能进行了评价,考查了实验条件,如催化剂用量,烧结温度,掺杂量等对催化剂催化活性的影响。Pr2O3的掺杂阻碍了TiO2晶相由锐钛矿型向金红石型的转变,使TiO2的粒径减小,比表面积增大,催化活性增强。当Pr掺杂量为0.8%,催化剂用量为0.03g,烧结温度为500℃时,酸性品红的降解率达到97%以上,酸性品红的降解反应为准一级反应。  相似文献
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强辐射催化法提纯多晶硅   总被引:1,自引:0,他引:1       下载免费PDF全文
陈应天  何祚庥 《物理学报》2011,60(7):78104-078104
将低纯度的金属硅,提纯成可用于制造太阳能电池的高纯硅材料的主要关键, 是去除材料中的硼杂质.本文提出了一种采用特殊的造渣过程以去除硼杂质的新方法.在这种新方法中,为了促进快速的化学反应,采用高密度的光子作为催化剂,以达到太阳能级硅材料的标准.本文对使用这种新的强辐射催化法炼硅的高温工具、冶炼方法、材料配方、材料的混合、以及渣剂的分离等关键技术,进行了详尽的公开和讨论,并在强辐射光催化原理的研究方面提出了一些探索性的机理.为了方便读者使用本文所提出的方法,建立起一套完整的提炼太阳能级硅材料的工业系统,本文也 关键词: 多晶硅提纯 光催化 太阳炉 除硼 除磷 多晶硅  相似文献
3.
采用特殊液相沉淀法制备纳米级的TiO2/SnO2复合粒子,对制备的纳米TiO2/SnO2采用XRD、TEM等手段进行了表征。用它做催化剂在日光下对甲基橙溶液进行了光催化实验。结果表明,纳米级TiO2/SnO2复合催化剂比纯TiO2的催化活性好,当SnO2摩尔百分数为20%时效果最佳,在60min内对10mg/L的甲基橙水溶液的降解率高达90.2%,具有较好的光催化活性。  相似文献
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We find that PL intensity I(t) of SrTiO3 thin film measured under UHV condition increases with UV-laser illumination over long time scale of ∼ 2 h. The intensity increase takes place at lower sample temperature as well, 200, 100 K, and 20 K. When O2 and N2 gas are introduced into the sample chamber the PL intensity decreases with the UV-illumination time, opposite to the UHV-case. We consider a quantitative thermal energy flow model of the laser-power and heat absorption by the sample, but find that temperature change of the sample is not large enough to account for the time dependent I(t). We propose photo-catalysis effect on STO surface as possible scenario of the PL intensity change.  相似文献
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Bi2SiO5 modified Si nanowire array films were fabricated as photo-catalysts via dip-coating Bi(NO3)3 on silver-assisted electroless wet chemical etching Si nanowires and subsequently annealing. The structures and morphologies of as-prepared samples are characterized by X-ray diffraction, Fourier transform infrared spectrum, scanning electron microscopy and transmission electron microscopy. The results of photocatalytic experiments indicated that the Bi2SiO5 modified Si nanowire arrays benefit the improvement for efficient electron-hole separation and photo-catalytic stability, thereby possessing superior photo-degradation performance. These hybrid nanowire arrays will be promising materials for photo-catalysts and degradation agents.  相似文献
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Highly ordered Au-Ti-SBA-15 mesoporous molecular sieves were successfully synthesized by one-pot hydrothermal synthesis in acid medium, and were characterized by XRD, UV-vis, SEM, element-mapping, HRTEM, N2 adsorption, XPS, 29Si MAS NMR, NH3-TPD and FT-IR. The as-prepared Au-Ti-SBA-15 samples were possessed of highly ordered mesostructures with larger pore diameter, pore volume and uniform mesopore size distribution. In the oxidation of styrene with H2O2 as the oxidant over Au-Ti-SBA-15 catalyst under photo-irradiation, reaction parameters, such as molar ratio of H2O2 to styrene, reaction time, solvent, the amount of catalyst, catalyst species, and the amount of 3% NaOH, were conditioned at length. As a result, highly selective epoxidation of styrene over catalyst was carried out perfectly for 10 min with high TOF of 4.75 × 103 min−1.  相似文献
7.
V2O5-TiO2 layers with a sheet-like morphology were synthesized by micro arc oxidation process for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). Phase structure and chemical composition of the layers were also studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. It was revealed that the composite layers had a sheet-like structure average thickness of which was about 100 nm depending on the applied voltage. The layers consisted of anatase, rutile, and vanadium pentoxide phases fractions of which varied with the applied voltage. The optical properties of the layers were also examined employing a UV-vis spectrophotometer. It was found that the absorption edge of the grown composite layers shifted toward the visible wavelengths when compared to MAO-synthesized pure titania layers. The band gap energy of the composite layers was calculated as 2.58 eV. Furthermore, photo-catalytic performance of the layers was examined by measuring the decomposition rate of methylene blue under ultraviolet and visible irradiations. The results demonstrated that about 90% and 68% of methylene blue solution was decomposed after 120 min ultraviolet and visible irradiations over the composite layers, respectively.  相似文献
8.
Nano-crystalline titanium oxide powder was synthesized by reactive plasma processing using titanium hydride as the precursor powder. Photo-catalytic properties of the product were evaluated by monitoring the degradation of methylene blue dye solution. The photo-catalytic activity of plasma-synthesized nano-sized titania powder could be enhanced considerably by incorporating surface Ti3+ sites and hydroxyl groups. Thermal treatment of the as-synthesized powder in flowing Ar–H2 helped to incorporate surface Ti3+ and hydroxyl species, resulting in considerable increase in the catalytic activity. Subsequent hydrothermal treatment of the powder led to a five-fold increase in the photo-catalytic activity.  相似文献
9.
TiO2 and TiO2/ZnO double layer films were sputtered on glass substrates. It was found that a thin ZnO underlayer is helpful for tailoring the microstructure and surface morphology of the TiO2 film. By applying a 70-nm-thick ZnO underlayer, a TiO2 thin film of 100 nm in thickness with well crystallized anatase phase and rough surface was successfully fabricated without heating the substrate. Relatively high photo-catalytic activity and good hydrophilic properties were observed in such TiO2/ZnO double layer films.  相似文献
10.
自行搭建了用于研究表面光催化的宽带红外和频振动光谱并可以原位紫外光激发的装置. 利用自制的结构紧凑小巧的高真空样品池,可以在10 kPa氧气氛围下经原位紫外光照除掉 射频磁控溅射制备的二氧化钛薄膜表面的有机污染物. 通过在室温下改变甲醇气压和指认吸附在薄膜表面的甲醇的和频振动光谱,发现薄膜表面有两种吸附的甲醇,分子形式吸附的甲醇(CH3OH)和解离吸附的甲醇(CH3O). 当甲醇的覆盖度由低变高时,分子形式吸附的甲醇的CH3的对称伸缩振动和费米共振峰红移了6~8 cm-1. 真空下,薄膜表面的甲氧基和表面的氢原子可以重新结合并以甲醇分子的形式脱附. 研究表明二氧化钛薄膜体系存在两个平衡:气相甲醇和表面吸附的甲醇分子之间,以及表面吸附的甲醇分子和甲氧基之间.  相似文献
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