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41.
超临界流体干燥法制备纳米TiO2-ZnO复合催化剂及其对苯酚降解的光催化性能 总被引:15,自引:0,他引:15
以TiCl4和Zn(NO3)2·6H2O为原料,采用溶胶-凝胶法结合超临界流体干燥法制备了纳米级TiO2-ZnO(7~10nm)复合催化剂,并用XRD和TEM等手段进行了表征.以苯酚光催化降解为模型反应对所制备催化剂的催化性能进行了评价.结果表明,与单组分TiO2及普通干燥法制备的TiO2-ZnO催化剂相比较,纳米TiO2-ZnO复合粒子的光催化活性有较大提高.用超临界干燥法制备的催化剂具有粒径小、分布窄、比表面积大、分散性好和光催化活性高等特点.采用超临界流体干燥法可直接制得纳米TiO2(锐钛矿型)-ZnO(非晶态)复合催化剂,可实现干燥、晶化一步完成.复合催化剂中ZnO的最佳掺入量为x(ZnO)=0.8%.超临界流体干燥法是制备纳米材料的一种新技术,具有产物容易收集和溶剂可回收利用等优点. 相似文献
42.
制备了一类以α-噻吩甲酰基三氟丙酮(TTA)为第一配体、2,2′-联吡啶(Dipy)为第二配体的共掺杂铕钆配合物Gd0.5Eu0.5(TTA)3Dipy。用其作为发光层材料制作了电致发光器件:ITO/PVK:Gd0.5Eu0.5(TTA)3Dipy/PBD/Al。讨论并证明了Gd3 与Eu3 之间存在F rster能量传递。研究了铕钆配合物与PVK共掺杂体系的激发光谱和光致发光谱,发现两者之间存在着能量转移,说明Gd3 的加入抑制了PVK自身的本征发光,促进了PVK到Eu3 的能量传递,得到了单色性很好的红光。 相似文献
43.
Pd/ZnO催化剂的还原及其催化甲醇水蒸气重整制氢 总被引:1,自引:0,他引:1
考察了共沉淀法制备的15.9%Pd/ZnO催化剂的还原对甲醇水蒸气重整制氢反应的影响.结果显示,当催化剂的还原温度为523~573K时,523K下反应的甲醇转化率达到了41.6%,CO2选择性为94.6%,出口CO浓度为1.26%.X射线衍射结果显示,当催化剂的还原温度为523K时PdZn合金开始形成.还原温度为523~573K范围内催化剂活性的提高归因于5~14nmPdZn合金粒子的存在.用程序升温还原及X射线衍射表征手段探究了还原过程中Pd与ZnO之间的相互作用.结果表明,Pd/ZnO可能经历了PdO/ZnO→Pd/ZnO→PdZnO1-x/ZnO→PdZn合金/ZnO的还原过程,而部分PdZn合金在反应过程中可重新被氧化成PdZnO1-x.对反应的活性物种进行了初步探讨. 相似文献
44.
45.
Zhiyue Han Yinghao Zhang Qian Yao Zhiming Du Chunlin He Jingchang Zhang 《Journal of heterocyclic chemistry》2016,53(1):325-331
Bis (1, 5‐diamino‐4‐methyl‐tetrazolium) azotetrazolate ( BMDATZT ) was synthesized with high yield in this work. The yield is 97.46%. The structure was characterized by IR, 1H NMR, and MS. The single crystal of BMDATZT?2H2O was first cultivated. The heat of formation, detonation pressure, and detonation velocity were first calculated. The crystalline density of BMDATZT?2H2O is 1.573 g/cm3. BMDATZT has high detonation pressure and detonation velocity (P =25.06 GPa, D = 7.805 km s?1), which are higher than those of 2,4,6‐Trinitrotoluene (TNT). Its thermal and mechanical sensitivities are moderate. Therefore, it is a kind of insensitive nitrogen‐rich energetic ionic salt with good performance, and it has potential application prospect in gas generating agent, explosive and solid propellant. 相似文献
46.
Chengren Li Jingchang Sun Xudong Ren Xishuang Yue Yingshi He 《Optics Communications》2012,285(17):3665-3668
The parameter identifiers and synchronization controllers are designed based on stability theory in order to realize the synchronization of two chaotic systems with diverse structures and the parameter identification of the uncertain system. The stimulated Raman scattering and NH3 laser are taken as examples. The simulation results show that the global synchronization between the uncertain stimulated Raman scattering and the NH3 laser can be achieved, and all the parameters in the stimulated Raman scattering system can be identified simultaneously. The method is proved effective and feasible. 相似文献
47.
Study on the deactivation and regeneration of the ZSM-5 catalyst used in methanol to olefins 总被引:1,自引:0,他引:1
ZSM-5 zeolite catalyst modified by a trace of metal cations shows high activity and high selectivity for the reaction of methanol to olefins (MTO), but it inclines to deactivate during the reaction. In this paper, the mechanism of the catalyst deactivation and the regeneration method were studied by X-ray diffraction (XRD), N2 adsorption-desorption, infrared spectra (IR), and infrared spectra coupled with NH3 molecular probes (IR-NH3). These characterizations indicated that coke formation was the main reason for the catalyst deactivation. To regenerate the deactivated catalyst, two methods, i.e., calcination and methanol leaching, were used. N2 adsorption-desorption, IR and IR-NH3 characteriza-tions showed that both methods can eliminate coke deposited on the catalyst and make the catalyst reactivated. XRD showed that the structure of the catalyst did not change after regeneration. Interestingly, the regenerated catalyst even showed better catalytic performance of the MTO reaction than the fresh one. Besides, the calcination regeneration can eliminate coke more completely, however, the methanol leaching method can be more easily carried out in situ in the reactor. 相似文献
48.
ZhiKun Zhang Yuzhi Zhang Jiming Bian Jingchang Sun Fuwen Qin Yuxin Wang Mengke Li Dong Zhang Yingmin Luo 《Applied Physics A: Materials Science & Processing》2013,111(4):1071-1076
ZnO nanorods (NRs) were grown perpendicularly on graphite substrates using low-temperature wet chemical bath deposition (CBD) with sputtered ZnO film as seed layer. The individual ZnO NRs exhibit single-crystalline feature with well defined hexagonal prism shape and smooth side facets. The high optical qualities of ZnO NRs on graphite substrates were demonstrated by the dominant near-band edge emission and nearly undetectable deep level emissions in room-temperature photoluminescence spectra. The extremely low average reflectance of 0.45 % was obtained for the ZnO NRs/graphite structure in the spectra range from 200 to 1100 nm, indicating that the reported ZnO NRs/graphite structures have significant opportunity for potential application in high-performance photovoltaic devices. Considering the excellent material characteristics of ZnO NRs and the versatile and fascinating features of graphite substrates, the achievements make it possible for the development of high-performance ZnO-based nano-devices even in transferable, flexible, or stretchable forms. 相似文献
49.
Navier-Stokes analysis of a circulation control airfoil 总被引:2,自引:0,他引:2
The two-dimensional, compressible, mass-averaged Navier-Stokes equations are used to investigate flows about a typical circulation
control airfoil. The governing equations are solved using the implicit approximate-factorization algorithm of Beam-Warming
with a modified algebraic eddy viscosity model. Results are compared with experimental data, and excellent agreement is obtained.
The effects of different jet momentum coefficients and angles of attack on the flow are studied. The mechanism of genenating
large lift by circulation control is discussed. 相似文献
50.
重点报道列阵GaAs-AlGaAs激光器相对强度噪声的测量结果,并和单元器件作了比较.实验测量包括相对强度噪声和驱动电流、调制频率以及温度的关系,并验证了在这些情况下相对强度噪声在激光器处于阈值时具有最大值的理论予言. 相似文献