ZnO纳米棒的制备与气敏性能的研究

以Zn(NO3)2·6H2O和NaOH为原料,CTAB为表面活性剂,通过微波辅助液相反应过程在低温下成功地制备了ZnO纳米棒.X射线衍射谱和扫描电镜结果表明,产物是六方纤锌矿结构ZnO纳米棒,长度为5～30μm,直径为0.1～1μm.气敏性能测试表明,所制备的ZnO纳米棒对H2S气体具有较好的选择性,但灵敏度不高.对ZnO纳米棒进行In掺杂后,对H2S气体的灵敏度和选择性大幅提高,在工作温度为332℃时,对体积分数为50X10-5的H2S灵敏度为29.217,说明In掺杂的ZnO纳米棒是有潜力的探测H2S气体的气敏传感器材料.     

溶胶-凝胶法制备碳纳米管/ZnO纳米复合材料及其氨敏性研究

以碳纳米管为模板,采用溶胶-凝胶法合成了碳纳米管(CNT)/ZnO纳米复合材料,用XRD、TEM、IR和EDS对产物进行了表征,研究了用该材料制成的气敏元件在室温下对NH3的气敏性。结果表明,产物是由ZnO均匀包裹在碳纳米管上构成的一种纳米复合材料,管径约50~60nm。这种复合材料可大大降低元件的阻值,提高元件的灵敏度。当碳纳米管加入量为60%[与Zn(CH3COO)2.2H2O的摩尔比]时,元件灵敏度最大,且灵敏度随NH3浓度的增大而增大,NH2从100ppm(10-6)以后,灵敏度变化平缓。     

ZnO/聚噻吩复合材料制备及紫外光激发室温气敏性能

采用两步法制备ZnO/聚噻吩(ZnO/PTh)复合材料,首先制备富含氧空位缺陷的ZnO,然后以此为载体,通过噻吩单体的原位聚合得到最终产物。通过X射线衍射、场发射扫描电镜、高分辨透射电镜、红外光谱、紫外-可见漫反射光谱和荧光光谱对合成材料进行表征,研究了其紫外激发室温气敏性能,分析了紫外激发气敏机理。结果表明:紫外光激发下复合材料室温下对乙醇有较高的灵敏度,对100×10-6乙醇的灵敏度达到12. 6,响应和恢复时间均在40s以内。     

ZnO纳米棒的微波合成及Pt掺杂对其气敏性能的改善

以Zn(NO3)2·6H2O和NaOH为原料,CTAB为表面活性剂,微波加热到90℃,反应30min,成功制备了ZnO纳米棒.X射线衍射仪(XRD)和扫描电镜(SEM)结果表明,产物是六方纤锌矿结构ZnO纳米棒,长度为1～5μm,直径为50～100nm左右.对ZnO纳米棒进行了Pt掺杂,并对掺杂前后的气敏性能进行了对比...     

介孔硅基WO3纳米颗粒薄膜室温气敏元件特性

采用双槽电化学腐蚀法在p＋单晶硅片表面制备介孔硅层（meso-PSlayer）,然后用对向靶磁控反应溅射法在介孔硅表面沉积WO3纳米颗粒薄膜,在干燥空气中于400℃下保温4h进行退火热处理,制备出介孔硅基WO3纳米颗粒薄膜（WO3-PS）室温气敏元件.利用扫描电子显微镜（SEM）分析介孔硅层及WO3-PS的表面形貌,通过X射线衍射（XRD）研究WO3的结晶状态,测试WO3-PS气敏元件在室温下对NO2、NH3的气敏性能,并探讨了WO3-PS气敏元件的工作机理.实验结果表明,在介孔硅表面沉积WO3纳米颗粒薄膜可使介孔硅的气敏性能显著提高,其中在室温下对10×10^-6NO2的灵敏度由5提高至56,大大提高了介孔硅的灵敏度,并降低了其响应/恢复时间,提高了对NO2的选择性.     

In2O3纳米孔材料的制备及其甲醛气敏性能研究

以In(NO3)3·4.5H2O为主要原料,采用溶剂热法成功地制备出In2O3纳米孔材料.采用X射线粉末衍射、透射电子显微镜等对样品的物相和形貌进行了表征和分析,并系统研究了其气敏性能.结果表明,成功合成的六方相In2O3纳米孔材料,其孔径小于17nm,孔道形状复杂且相互连通,以该材料制成的气敏元件对甲醛有很好的气敏性能,对50×10-6甲醛的灵敏度高达23.6.     

聚噻吩掺杂纳米ZnO的制备及气敏性能

利用水热法制备了纳米ZnO颗粒,同时采用聚噻吩对其原位改性,利用X射线粉末衍射仪、扫描电镜和红外光谱对所制ZnO复合材料的结构和形貌进行表征分析。将合成的改性ZnO纳米颗粒用于传感材料,研究了其在检测挥发性有机物中的气敏性能。结果表明:聚噻吩掺杂纳米ZnO有利于复合材料气敏性能的提高,添加量不同对丙二醇的选择性和响应有明显影响,当掺杂量为10%(质量分数)时,对5×10-6的丙二醇的响应达到14。说明聚噻吩改性的纳米ZnO是可以有效检测丙二醇的气敏性材料。     

花状SnO2的制备及其气敏特性的研究

以乙二醇(C2H6O2)为有机溶剂,采用溶剂热法制备了花状SnO2纳米材料,并将制备的SnO2制成旁热式气敏元件.通过XRD,SEM等测试手段对SnO2纳米材料进行了表征,并初步分析了气敏元件对丙酮的敏感机理.制备的SnO2材料是由粒径约为10 nm的颗粒有规则的堆叠而成的直径约为3～4μm的花瓣清晰的多孔分级花状结构.研究发现,气敏元件对丙酮气体有很好的响应灵敏度.在最佳工作温度(350℃)时,检测的丙酮体积分数最低为1×10-6.对100 ppm丙酮的响应及恢复时间分别为40和50 s.且气敏元件对丙酮气体的响应灵敏度远高于对苯、甲苯、甲醇、甲醛、氨等气体的响应灵敏度.     

Pd掺杂纳米ZnO的燃烧法制备及性能研究

以酒石酸为燃料,硝酸锌为氧化剂,采用溶液燃烧法制备了Pd(0~7%(原子分数))掺杂纳米Zn O。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和荧光光谱仪对产物了进行表征,重点讨论了掺杂对Zn O气敏性能的影响。结果表明,在330℃测试条件下,纯Zn O和7%(原子分数)Pd掺杂Zn O气敏元件对体积分数为5.0×10-5的乙醇气体灵敏度分别为21.4和11.2;元件对5.0×10-5丙酮气体的灵敏度分别为2.0和8.8。Pd掺杂显著提高了元件对乙醇和丙酮气体的选择性。     

水热法制备V_2O_5掺杂纳米In_2O_3及其气敏性能研究

以硝酸铟为原料,采用水热法制备氧化钒(V2O5)掺杂的氧化铟(In2O3)纳米复合材料。利用X射线衍射(XRD)和比表面测试仪对材料的物相结构和比表面积(BET)进行了表征测试。结果表明:制备的In2O3材料都为立方晶相,具有较大的比表面积。V2O5的掺杂提高了对乙醇、苯的灵敏度。复合材料中掺杂V2O50.5%(wt,质量分数)的In2O3气敏元件对乙醇具有较好的气敏性能,3.0V加热电压下对5×10-6乙醇的灵敏度达8.024,响应恢复时间短。     

Effect of MWCNTs/ZnO inorganic fillers on the electrical,mechanical and thermal properties of SiR-based composites

Rubber insulation materials were widely used in the fields of electrical and electronic engineering, especially, which have excellent nonlinear electrical conductivity and can be employed to homogenize the electric field distribution of cable accessories. To enable the rubber materials, such as silicon rubber (SiR), to possess excellent nonlinear electrical conductivity has been a hot issue. In this paper, MWCNTs/ZnO inorganic fillers were prepared by mixing a small amount of multi-wall carbon nanotubes (MWCNTs) with zinc oxide (ZnO) nanosheets, and MWCNTs/ZnO/SiR composites were prepared. The macroscopical properties results show that the nonlinear electrical conductivity characteristics can be induced by filling appropriate content of MWCNTs/ZnO fillers, and the threshold field strength corresponding to the nonlinear conductivity gradually decreases with the increase of MWCNTs filling content, which further decreases with the increase of measured temperature. The COMSOL simulation results also verify that MWCNTs/ZnO/SiR composite with nonlinear conductivity can effectively reduce the electric field strength at the stress cone of cable accessories. In addition, the thermal conductivity and tensile strength for MWCNTs/ZnO/SiR composite are also improved comparing to pristine SiR. This work demonstrates MWCNTs/ZnO/SiR composites possess outstanding overall properties and have good potential to be used in the cable accessory.

     

Mechanical properties of porous Al2O3 composite with surface modified multi-walled carbon nanotubes (MWCNTs)

Multi-walled carbon nanotubes (MWCNTs) have been reinforced in alumina (Al2O3) matrix to overcome the inherent brittleness of the Al2O3 matrix. In this work, MWCNTs were treated by acid to provide hydrophilicity to hydrophobic MWCNTs, inducing the homogeneous dispersion of MWCNTs in an aqueous solution. Aluminum hydroxide (Al(OH)3) as a Al2O3 precursor was added in the solution with the modified MWCNTs, and then this mixture solution was filtered at room temperature. The prepared powders were calcinated at 800-1000 degrees C to reduce the gas pocket in the matrix by decomposition of Al(OH)3. Then the calcinated powders were formed, and heat-treated. The porous MWCNTs-Al2O3 composites show higher mechanical properties in flexure strength and hardness than the porous Al2O3 without the reinforcement phase, which is attributed to the high mechanical properties of MWCNTs. However, higher MWCNTs contents in the composites decrease the mechanical properties due to the aggregation of MWCNTs in the composites. Therefore, control of the MWCNTs content and its dispersibility in the matrix are key factors to be considered for the fabrication of the porous MWCNT-Al2O3 composites.     

ZnO nanomaterials based surface acoustic wave ethanol gas sensor

ZnO nanomaterials based surface acoustic wave (SAW) gas sensor has been investigated in ethanol environment at room temperature. The ZnO nanomaterials have been prepared through thermal evaporation of high-purity zinc powder. The as-prepared ZnO nanomaterials have been characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray Diffraction (XRD) techniques. The results indicate that the obtained ZnO nanomaterials, including many types of nanostructures such as nanobelts, nanorods, nanowires as well as nanosheets, are wurtzite with hexagonal structure and well-crystallized. The SAW sensor coated with the nanostructured ZnO materials has been tested in ethanol gas of various concentrations at room temperature. A network analyzer is used to monitor the change of the insertion loss of the SAW sensor when exposed to ethanol gas. The insertion loss of the SAW sensor varies significantly with the change of ethanol concentration. The experimental results manifest that the ZnO nanomaterials based SAW ethanol gas sensor exhibits excellent sensitivity and good short-term reproducibility at room temperature.     

石墨烯多壁碳纳米管/超高分子量聚乙烯导电复合材料的制备及性能

为了比较超高分子量聚乙烯(UHMWPE)在单一填充和混合填充时, 复合材料导电性的差别。在超声和肼的作用下, 通过对氧化石墨烯(GO)、 多壁碳纳米管(MWCNTs)和超高分子量聚乙烯水/乙醇分散液减压蒸馏及热压制备了隔离型MWCNTs/UHMWPE、 石墨烯(GNS)/UHMWPE和MWCNTs-GNS/UHMWPE导电复合材料。经SEM、 TEM测试发现, 导电填料分散于UHMWPE颗粒表面, 热压后形成隔离结构。隔离型的MWCNTs/UHMWPE和GNS/UHMWPE复合材料均表现出较低的导电逾渗(0.148%和0.059%, 体积分数,下同), 但MWCNTs/UHMWPE复合材料的电导率(2.0×10^-2 S/m, 1.0%, 质量分数, 下同)明显高于相同填料含量下的GNS/UHMWPE复合材料。 MWCNTs-GNS/UHMWPE复合材料表现出了更低的逾渗(0.039%) 和较高导电性能(1.0×10^-2 S/m, 1.0%), 其拉伸强度和断裂伸长率随填充剂含量的增加呈现出先上升后下降的趋势。     

Co3O4中空纳米球的可控制备及气敏性能

以碳纳米球为模板,采用硬模板法制得多孔Co_3O_4中空纳米球。分别采用SEM、XRD、FTIR、BET和XPS对Co_3O_4纳米球的形貌和结构进行表征。通过改变前驱体浓度和陈化反应时间调控Co_3O_4中空纳米球的空间结构及气敏性能。结果表明:在前驱体浓度为0.1mol/L、陈化时间为48h时,得到的Co_3O_4中空纳米球的表面呈疏松多孔结构。Co_3O_4中空纳米球直径约为500nm,由40nm的Co_3O_4纳米粒子组成。室温下,由该材料组装的气敏传感器对浓度为100×10^-6～0.5×10^-6的NH_3有较好的气敏性能;对浓度为100×10^-6的NH_3响应灵敏度高达155.8%,响应时间为1.3s。该气体传感器对NH_3的最低检测限为0.5×10^-6。     

Microwave-assisted synthesis of ZnO/MWCNT hybrid nanocomposites and their alcohol-sensing properties

Zinc oxide and multi-walled carbon nanotube (ZnO/MWCNT) hybrid nanocomposites were synthesised by microwave-assisted method using the mixed solution of zinc acetate dehydrate (Zn(CH₃COO)₂·2H₂O) and treated MWCNTs. The syntheses were carried out at various microwave irradiation powers. The characterisation of the as-synthesised nanocomposites was conducted by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results revealed that the composites were composed of two phases of MWCNTs and hexagonal wurzite ZnO. The SEM results showed that the ZnO nanoparticles were well decorated on the surface of MWCNTs. The amount of ZnO nanoparticles and their size increased with increasing irradiation power. Thick-film sensors were fabricated onto interdigitated conducting electrodes using as-synthesised hybrid composites as sensing materials. The alcohol-sensing behaviour of the hybrid composite films was investigated. The results indicated that the irradiation power had significant influence on the sensing response of the sensors toward alcohol. The sensor fabricated from the composite synthesised at higher irradiation power exhibited an enhanced alcohol-sensing performance.     

Performance evaluation of ZnO–CuO hetero junction solid state room temperature ethanol sensor

A semiconductor ethanol sensor was developed using ZnO–CuO and its performance was evaluated at room temperature. Hetero-junction sensor was made of ZnO–CuO nanoparticles for sensing alcohol at room temperature. Nanoparticles were prepared by hydrothermal method and optimized with different weight ratios. Sensor characteristics were linear for the concentration range of 150–250 ppm. Composite materials of ZnO–CuO were characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR) and high-resolution transmission electron microscopy (HR-TEM). ZnO–CuO (1:1) material showed maximum sensor response (S = R_air/R_alcohol) of 3.32 ± 0.1 toward 200 ppm of alcohol vapor at room temperature. The response and recovery times were measured to be 62 and 83 s, respectively. The linearity R² of the sensor response was 0.9026. The sensing materials ZnO–CuO (1:1) provide a simple, rapid and highly sensitive alcohol gas sensor operating at room temperature.     

Multiwalled carbon nanotubes anchored with SnS2 nanosheets as high-performance anode materials of lithium-ion batteries

A nanocomposite of multiwalled carbon nanotubes (MWCNTs) anchored with SnS(2) nanosheets (NS) (SnS(2) NS@MWCNTs coaxial nanocables) has been synthesized through a simple solution-based method at room temperature. The synthetic mechanism of these intriguing nanocomposites is proposed as electrostatic attraction between tin ions and MWCNTs, followed by the nucleation and two-dimensional growth of SnS(2). The as-synthesized SnS(2) NS@MWCNTs coaxial nanocables have been applied as anode materials for lithium-ion batteries, which show better lithium storage performance compared to pure SnS(2) nanosheets and MWCNTs. The combination of MWCNTs that can hinder the agglomeration and enhance electronic conductivity of the active materials might be responsible for the enhanced cyclic performance.     

The role of functionalized carbon nanotubes in a PA6/LCP blend

Multi-walled carbon nanotubes (MWCNTs) were carboxyl-functionalized in order to improve their dispersion in a polymer matrix. The carboxyl-functionalized MWCNTs (i.e., MWCNT-COOH) were added into a blend matrix consisting of polyamide 6 (PA6) and liquid crystalline polymer (LCP) (PA6:LCP = 80:20 in weight) to make ternary composites. The effects of MWCNT-COOH on the rheological, physical, morphological, thermal, mechanical, and electrical properties of the ternary composites have been examined systematically. The dispersion of MWCNTs in the polymer matrix and their interactions with the polymers (i.e., PA6 and LCP) were found to be the most important factors affecting all properties. The functionalization of MWCNTs resulted in the significant improvement in their dispersion in the polymer matrix and largely enhanced the interactions of MWCNTs with the polymer matrix. The functionalized MWCNTs acted not only as reinforcement fillers but also as a compatibilizer that could enhance the interfacial adhesion between PA6 and LCP. Interestingly, the packing density of the polymer matrix was greatly increased by adding MWCNT-COOH.     

分级介孔结构组成的ZnO微球及光催化性能

以硝酸锌、脲素及酒石酸为反应物, 采用水热法制备碱式碳酸锌前驱体微球, 通过煅烧前驱体制备了介孔氧化锌微球。通过扫描电子显微镜(SEM)可以观察到, 氧化锌微球的直径约为2~4 μm, 由大量厚度约为10 nm的介孔纳米片组装而成。X 射线衍射(XRD)和透射电镜(TEM)结果表明: ZnO微球为六方纤锌矿结构, 并结晶较好。比表面积测试(BET)表明ZnO微球为介孔材料, 孔径为20~50 nm, ZnO微球比表面积约为29.8 m²/g。以亚甲基蓝为目标降解物, 对介孔氧化锌微球进行了光催化降解实验。实验结果表明, 所合成的介孔ZnO微球对亚甲基蓝的光催化性能较好。