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Vanadium oxide/titanate composites nanorods (VOx/ Titanate-CNRs) were synthesized in high yield by using titanate nanotubes as templates and V2O5·nH2O sol as the precursors under hydrothermal conditions (200 ℃, 48 h). Samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive analysis by X-ray (EDAX). X-ray diffraction structure determination showed that this new phase had the composition of V3O7·H2O and crystallized with orthorhombic symmetry. SEM and TEM tests showed that the samples were uniform straight rods with the diameter range from around 100 to 300 nm and the length over 10 μm. The chemical compositions of the samples were determined with EDXA. The electrochemical tests of samples (titanates nanotubes, V2O5 and VOx/ Titanate-CNRs) prove that VOx/ Titanate-CNRs exhibit a better electrochemical performance. 相似文献
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磁性Fe3O4 /壳聚糖的化学修饰及包覆机理研究 总被引:1,自引:0,他引:1
Nano-sized Fe3O4 powder was prepared through an Oxygenation-Hydrothermal method. The chitosan magnetic complex was prepared by coating chitosan on the surface of Fe3O4 powders through Microlatex-Crosslinking Method. The product was characterized by IR, XRD, TEM, Vibrating Sample Magnetometer (VSM), TG methods. Results show that the as-prepared powder is 25 nm in size and shows supermagnetism. The content of magnetite in microspheres is 37.8%. The mechanism for the coating reaction of chitosan to Fe3O4 nanoparticles is also suggested. 相似文献
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Li4Ti5O12溶胶-凝胶法合成及其机理研究 总被引:15,自引:0,他引:15
The precursors of Li4Ti5O12 were prepared from tetrabutyl titanate and lithium acetate by sol-gel process. The Li4Ti5O12 samples were synthesized by calcining the gel precursors at 400~900 ℃ in air for 6~20 h. Its reaction mechanism was investigated by infrared spectroscopy(IR), thermogravimetry(TG) and X-ray diffraction(XRD). The effects of sinter-temperature, calcination-time and thermal-treatment for the products were discussed. The samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM). The results showed that the single-phase products were obtained by calcining the gel precursors at 800 ℃ in air for 20 h, the sinter-temperature was lower than that of solid-state method, the particles were narrowly distributed, well crystallized with a size range from 0.3μm to 0.5 μm. 相似文献
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以工业固体废弃物粉煤灰漂珠(fly ash cenospheres, FACs)为载体, 采用水热法制备了新颖的漂珠负载Bi2WO6复合材料(Bi2WO6/FACs), 通过X射线衍射(XRD), 扫描电子显微镜(SEM), X-射线光电子能谱(XPS), 和紫外-可见漫反射光谱(DRS)技术对其进行了表征。XRD数据显示了正交相Bi2WO6的特征衍射峰。DRS结果证实了引入FACs后Bi2WO6对可见光的吸收增强。在可见光的照射下, 以亚甲基蓝溶液的光催化降解评价了Bi2WO6/FACs复合材料的光催化性能。结果表明:Bi2WO6/FACs的光催化性能优于纯Bi2WO6的, 其一级反应速率常数(k)为后者的2.4倍。尤其是由于漂珠质轻中空的特性, Bi2WO6/FACS复合光催化剂可长时间漂浮于水面, 既能充分吸收光能, 又有利于催化剂的回收和重复利用。 相似文献
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三叶结分子是最简单的非平凡纽结分子, C30卡宾三叶结分子是由一条闭合的(C≡C—)15 sp杂化碳链组成的, 是具有D3对称性的拓扑手性分子. 本文用密度泛函方法[DFT/RB3LYP/6-31G(D)]对分子结构和光谱性质进行了研究, 在优化构型的基础上通过自然键轨道(NBO)方法和轨道能级研究了它的共轭性、成键情况和稳定性, 并与平面型C30卡宾环分子进行了比较. 计算结果表明三叶结分子的三叶弧上形成了非平面的C≡C共轭和扭曲的内螺旋结构, 交叉处具有弱成键作用, 且分子轨道也发生了扭曲; 三叶结分子比卡宾环的共轭性和赝Jahn-Teller效应都明显小, 而总能量高. 因此, 分子打结是一个能量升高的过程. 相似文献
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Ni-P-Zn3(PO4)2(ZnSnO3、ZnSiO3)纳米复合化学镀层性质和组成的研究 总被引:10,自引:0,他引:10
研究了温度、时间、浓度等对A3钢片上Ni-P-Zn3(PO4)2、Ni-P-ZnSnO3和Ni-P-ZiSiO3纳米复合合化学镀层外貌的影响,用扫描电子显微镜(SEM)观察外貌、称重法测定厚度;通过10%NaCl溶液、1%H2S气体加速腐蚀试验,10%CuSO4溶液点滴试验等多种手段测定其耐腐蚀性能,用X-射线光电子谱(XPS)及俄歇电子能谱(SES)测定其价态组成,结果表明:在最佳施镀条件下,可得光亮、致密、耐腐蚀性强于A3钢、磷化膜及Ni-P镀层的纳米复合化学镀层,镀层的原子百分组成约为(%):Ni-P-Zn3(PO4)2:Ni70.00,P12.47,Zn3(PO4)213.93,C3.6;Ni-P-ZnSnO3;Ni77.56,P10.00,ZnSnO39.84,C2.6;Ni-P-NiSiO3,Ni83.00,P10.96,ZnSi5.15,C0.89. 相似文献
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研究无电镀镍镀层加入钻石微粒或PTFE微粒的均匀分散相 ,所得之复合镀层在 3.5%NaCl水溶液中的电化学分析 ,浸渍试验与临雾试验 ,皆显示复合镀层之耐蚀性低于不含微粒之无电镀镍镀层 .由SEM ,AES ,XRD ,EPMA分析镀层微观组成 ,复合镀层之磷含量分布呈差异性变化 ,磷量较多区域为微阴极 ,磷量较少区域为微阳极 ,复合镀层存在众多微电池组合 ,容易引起电化学伽凡尼腐蚀 ,造成复合镀层耐蚀性降低 ,当镀层微粒含量增加时 ,微粒的惰性保护效果超过微电池效应 ,复合镀层的耐蚀性质才能提高 相似文献
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Ni-P化学镀反应速率及机理研究 总被引:7,自引:0,他引:7
通过镀层分析和析氢量测量得到Ni-P镀层的沉积速度和H2PO2的分解速度·以混合电位理论为基础,对Ni-P电极在不同组成饮液中的极化曲线进行分解得到以化学镀电流形式所表示的反应速率·将两种方法所得结果进行对照,确定H2PO2氧化时电子迁移数为1,并用原子红-电化学联合理论解释溶液PH对反应速率及化学镀效率的景响. 相似文献
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S. F. Tikhov A. N. Salanov Yu. V. Palesskaya V. A. Sadykov G. N. Kustova G. S. Litvak N. A. Rudina V. A. Zaikovskii S. V. Tsybulya 《Reaction Kinetics and Catalysis Letters》1998,64(2):301-308
Main features of the formation of porous composites by hydrothermal treatment of powdered aluminium were studied by scanning
electron microscopy, TEM, XPD, IR spectroscopy of lattice modes, and thermal analysis. Hydrothermal oxidation of aluminium
was shown to proceedvia generation and subsequent oriented growth of well-crystallized boehmite platelets, whose subsequent dehydration yields γ-alumina.
Relation between the degree of the metal oxidation and specific surface area/crushing strength of the composites was analyzed. 相似文献
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采用酸性化学镀技术在Al2O3陶瓷片表面沉积Ni-P镀层,通过电感耦合等离子体发射光谱,X射线衍射光谱和扫描电子显微镜等分析测试,对镀层的成分、物相和形貌进行了表征,考察了表面活性剂种类、掺量等因素对镀层表面性貌和性能的影响。结果表明,当添加5 mg·L-1 SDS时,镀速从14 μm·h-1增加到17 μm·h-1,随表面活性剂添加量继续增加,镀速呈减少趋势。添加表面活性剂能够不同程度的消除化学镀Ni-P镀层固有的胞状组织,提高表面致密性和平整性;镀层自腐蚀电流密度从43 μA·cm-2减小至3.5 μA·cm-2,镀层的耐腐蚀性能显著提高。根据电化学理论和实验规律,探讨了表面活性剂在化学镀镍磷合金反应过程的影响机理。 相似文献