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1.
CuInS2@CdS core‐shell nanocrystals were prepared in a wet chemical process. Transmission electron microscope (TEM), x‐ray energy dispersive spectroscopy (EDAX), x‐ray diffraction (XRD), absorption, and photoluminescence (PL) spectra were used to confirm the formation of the CuInS2@CdS core‐shell structure. The growth of CdS shell not only increased the PL intensity, but also restrained the transformation of CuInS2 from nanoparticles to nanorods after annealing, which was attributed to an effective chemical passivation of the CuInS2 core by the CdS shell.  相似文献   

2.
A SnO2/CdS nanocomposite based on the flowerlike clusters of SnO2 nanorods was prepared and characterized with x-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and EDX analysis. The SEM and TEM images show the nanocomposite is composed of CdS nanoparticles and flowerlike clusters of SnO2 nanorods. The UV–vis spectrum of the nanocomposite displays a new absorption band in the region of 350 to 530 nm, compared with that of the flowerlike clusters of SnO2 nanorods. The measurement of optoelectronic property indicates that the photoresponse of the composite is extended into the visible region and the incident photon-to-current conversion efficiency (IPCE) of the composite is up to 6.5 in the range of 400 to 440 nm. These phenomena ought to be ascribed to the special nanostructure of the SnO2/CdS composite obtained.  相似文献   

3.
TG and DTA studies on Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2 were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading to the formation of Sn3(PO4)2 as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination reactions were proposed.  相似文献   

4.
Magnetic properties of Cr-doped SnO2 and the effects of oxygen vacancy (VO) on the magnetic properties are examined to understand the origin of ferromagnetism in Cr-doped SnO2 and explain the observed discrepant phenomena. Cr-doped SnO2 shows a p-d hopping ferromagnetic interaction that decreases gradually with the increase in Cr-Cr distance. In Cr-doped SnO2 with VO, ferromagnetic interaction is obviously weakened. Exchange constants indicate that the ferromagnetic exchange interaction in Cr-doped SnO2 is similar to that in Co-doped SnO2, while it is similar to that in Fe-doped SnO2 and/or undoped SnO2 with tin vacancy (VSn) in the presence of VO.  相似文献   

5.
本文概述了SnO2TiO2 复合半导体纳米薄膜的发展历史和研究现状,对比分析了“混合”、“核壳”和“叠层”3 种复合薄膜的结构和性能特点,着重论述了叠层结构的SnO2 /TiO2复合薄膜的光电化学和光催化特性。结合作者的研究工作,探讨了SnO2 /TiO2双层复合薄膜上下层厚度对其光催化活性的影响,指出复合薄膜光催化活性的提高可归因于电子从TiO2 向SnO2 的迁移。最后对SnO2 /TiO2复合薄膜的局限性和发展潜势做一简要分析,强调了该复合薄膜本身的应用特点。  相似文献   

6.
In this study, we present kinetics of phenol dyes removal by SnO2/Fe3O4 nanoparticles in a photocatalytic reactor for optimization of this process. The effect of different concentrations of SnO2 5, 10, 15, 20% w/w on the photocatalytic reactor during removal of phenol red was investigated. The SnO2/Fe3O4 nanoparticles were synthesized by core–shell method. The results of XRD and TEM showed the successful synthesis of these nanoparticles. Several other methods were applied to synthesis of these nanoparticles but none of them succeeded. This process composed of two-stage. The first stage was absorption by iron oxide nanoparticles and second stage was photocatalytic by tin oxide nanoparticles that followed pseudo-second-order kinetic and first-order kinetic, respectively. Optimization of this process was done corresponding to the parameters affecting the process with design expert software. In order to determine the optimal values of each of the parameters and the optimal conditions of the process, parameters were introduced to response surface methodology.  相似文献   

7.
A new method for the preparation of mesoporous ZnO/CdS@SiO2 core/shell nanostructure (CSN) has been developed. The mesoporous silica shells allow Ag+ to enter into the interior of the nanostructures to contact with ZnO/CdS core, accordingly causes the quenching of its band edge emission (475 nm) along with a simultaneous enhancement of red emission at around 595 nm. So, a novel visual fluorescence detection strategy for Ag+ ion is proposed based on a common core/shell Quantum dots nanostructure. Under optimal conditions, the enhanced fluorescence intensity at 595 nm increased linearly with the concentration of Ag+ ion ranging from 0.03 μM to 0.24 μM with a detection limit (3σ) of 3.3 nM.  相似文献   

8.
TiO2 films with a thickness of 75 ± 5 nm (anatase) were formed on SnO2-film (580 ± 80 nm) coated soda-lime glass substrates (SnO2/SL-glass) by a sol-gel method. Although the photocatalytic activity for CH3CHO oxidation (ex > 300 nm) significantly exceeded that of a standard TiO2/quartz sample, it decayed with illumination time (t) at t > 0.75 h. Stripes of anatase TiO2 films of 40 nm in thickness and 1 mm in width were prepared on the SnO2/SL-glass substrate in a 1-mm pitch by photolysis of an organically modified sol-gel film. The TiO2 patterning further increased the photocatalytic activity by a factor of 4.1 as compared to the non-patterned sample, and it was also maintained at 0 < t < 2 h. The flat band potentials of the TiO2 and SnO2 films are determined to be –0.34 and +0.07 V (vs. SHE), respectively, at pH = 7 by the Mott-Schottky plots. On the basis of the results, the outstanding patterning effects could be rationalized in terms of the vectorial charge separation at the interface between TiO2 and SnO2.  相似文献   

9.
In this work, the mechanochemical synthesis of a moderately agglomerated tin oxide (SnO2) powders and the subsequent preparation of semiconductor gas sensors as prototypes, were studied. Tin (II) chloride (SnCl2) powder was milled with calcium hydroxide (Ca(OH)2) and potassium carbonate, (K2CO3) powder, respectively, in a ball mill at room temperature and in an air atmosphere. Heat treatment of milled mixtures at 400 °C resulted in the formation of a tetragonal phase, confirmed by X-ray diffraction (XRD). During milling in the presence of water, a high number of hydroxide (OH) groups are formed at the surface. When SnCl2 was milled with K2CO3, no water was produced and the Fourier-transform infrared spectrum (FT-IR) of the powder has no surface hydroxyl deformations. On exposure to hydrogen sulfide (H2S) gas, the particles, prepared from anhydrous powder, have higher sensitivity than these, prepared from hydrated powder. The SnO2 thick film, prepared from anhydrous powder may be successfully applied to a H2S gas sensor.  相似文献   

10.
Pure SnO2, sulfated SnO2-SO4 2- and Pd supported on SnO2 and SnO2-SO4 2- were prepared from SnO2 precursor with high surface area, and used for CH4 deep oxidation. The catalysts were characterized by means of N2-BET, XRD, TG-DTA, XPS and TPD. SnO2-SO4 2- shows higher activity than SnO2, due to the presence of more active oxygen species, superacid sites and its higher BET surface area. Pd/SnO2 and Pd/SnO2-SO4 2- display essentially the same activity to each other, while it is much higher than the activity on SnO2 and SnO2-SO4 2-. The main reason is ascribed to the concerted action between Pd and the supports.  相似文献   

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