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超细纳米TiO2/Al2O3复合体的制备及其组成分布的研究 总被引:3,自引:0,他引:3
采用溶胶-凝胶法成功制备出纳米尺寸的TiO2/Al2O3复合体,并用XRD、XPS和IR等手段研究了复合体的结构组成及TiO2和Al2O2的分布状态,进一步探讨了机械研磨法制备TiO2/Al2O3复合体等因素对其组成的影响。XRD分析表明,在〔Al^+3〕:〔Ti^+3〕=1:1(或0.5)情况下,改进的溶胶-凝胶法制备纳米TiO2/Al2O3复合体,其TiO2主要分布在Al2O3的表面层,在含T 相似文献
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流动注射分析在线研究Cr(Ⅵ)在纳米TiO2表面上的吸附 … 总被引:2,自引:1,他引:1
用溶胶-凝聚法在不同的水解和热处理条件下制备了纳米尺寸的TiO2微粉,所得的TiO2表面性质迥异,粒径从几个纳米到数百个纳米,晶型也由低温煅烧的锐钛型转成高温地的金红石型。利用流动注射微柱富集在线分析方法对Cr离子在纳米TiO2表面上的吸附动力学特性进行了原位表征。 相似文献
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纳米TiO2微胶粒的光化应制备机理及量子尺寸效应 总被引:1,自引:0,他引:1
研究了由水相Ti^3+制备纳米极Ti^O2微胶粒的光化反应机理及反应动力学,给出反应速率方程。讨论了TiO2微胶粒的量子尺寸效应,经电镜测试TiO2粒子的直径为15-25nm。反应过程中由气相色谱仪监测生成物H2。 相似文献
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溶胶—凝胶法制备负载型TiO2膜的研究 总被引:1,自引:0,他引:1
本研究采用溶胶-凝胶(Sol-Gel)法制备了负载型TiO2膜,并采用SEM、压汞等实验手段对Ti(OH)4溶胶和TiO2膜进行了表征。实验表明:Ti(OH)4溶胶制备过程中H2O/Ti^4+、C2H5OH/Ti^4+的比值,溶胶在支承管上浸涂的时间、次数以及凝胶煅烧升温速度和煅烧温度均是制备负载型TiO2膜的重要因素。最终制得一种无裂纹、20μm厚、孔径分布在50 ̄300nm之间的负载型TiO2 相似文献
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TiO2纳米粒子膜表面性质的研究 总被引:14,自引:0,他引:14
TiO_2纳米粒子膜在光催化降解大气和水中的污染物[1]、光电转换[2]、光致变色[3]等方面有广阔的应用前景,近年来受到了科学界的高度重视.研究表明,膜的表面性质对如上应用有着重要影响.本文采用等离子体化学气相沉积法(PECVD法)[4]制备了TiO2的纳米粒子膜,分别采用TiCl4等离子体或O2等离子体处理膜表面,获得两种不同表面性质的TiO2纳米粒子膜;并利用表面光电压谱(SPS)和电场诱导表面光电压谱(EFISPS)技术对膜的表面性质进行具体分析,探讨了其在光催化领域的可能应用.1实验部… 相似文献
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Ru(bpy)2(NCS)2染料敏化CdS/Zn^2+—TiO2复合半导体纳米 … 总被引:9,自引:0,他引:9
采用水热法合成了Zn^2+离子掺杂的TiO2纳米粒子「Zn^2+掺杂量0.5%(物质的量的比)」,并用光电化学方面研究了经Ru(bpy)2(NCS)2(bpy=2,2’-bipyridine-4,4’-dicarboxylic acid)分别敏化的掺杂Zn^2+的TiO2电极(简写为Zn^2+TiO2)和CdS/Zn^+-TiO2复合半导体纳米多孔膜电极的光电化学行为。实验证明Ru(bpy)2(N 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献
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An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
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Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described. 相似文献
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用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在. 相似文献
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An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction. 相似文献
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The Diels-Alder reactivity of 1,2-heteroborines (H4C4B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed. 相似文献