共查询到19条相似文献,搜索用时 703 毫秒
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以ZnO纳米粉(平均粒径30 nm)和Fe2O3,纳米粉(平均粒径90 nm)为原料,利用传统的厚膜气敏传感器制备工艺,制备了纯ZnO多孔纳米固体厚膜气敏传感器和掺杂Fe2O3(掺杂量为1wt%,2wt%和5wt%)的ZnO厚膜气敏传感器.分别测试了这四种厚膜气敏传感器的本征电阻(传感器在空气中的电阻值)及其对乙醇,汽油,丙酮,对二甲苯,氢气,甲烷和CO敏感特性.结果表明:当工作温度在较低时,Fe2O13,的掺杂可明显降低ZnO多孔纳米固体厚膜气敏传感器的本征电阻,并提高其工作稳定性,而适量Fe2O3的掺杂可以提高ZnO多孔纳米固体厚膜气敏传感器对乙醇蒸气和汽油的灵敏度.结合对传感器厚膜的显微结构分析结果,我们对出现上述差异的原因进行了初步讨论. 相似文献
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采用物理热蒸发法制备ZnO纳米材料及不同质量分数(1%,3%,5%,wt,下同)Ag掺杂的ZnO纳米材料,制备成旁热式气敏元件,采用静态配气法对目标气体进行气敏性能测试。实验结果表明,Ag掺杂ZnO纳米材料较纯ZnO纳米材料对目标气体(酒精、甲烷、一氧化碳)的气敏性能有所提高。其中,Ag掺杂质量分数为1%的ZnO纳米材料气敏性能最佳,提高幅度分别达215%,128%和76%(C2H5OH,CH4,CO)。借助X射线衍射仪和扫描电子显微镜对所制得不同比例Ag掺杂的ZnO纳米结构进行表征,并对实验结果进行气敏性能分析,结合势垒模型和能带理论进行气敏机理分析。 相似文献
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通过溶剂热法(无水乙醇)制备了Cu2+(0~6mol%)掺杂ZnO纳米棒粉体,采用X射线衍射仪和扫描电镜对掺杂ZnO纳米粉体的晶体结构和微观形貌进行了表征.研究了Cu2+掺杂比例、溶剂热反应温度及时间对材料气敏性能的影响;考察ZnO(120℃,10h)和3mol%Cu2+掺杂ZnO(120℃,10h)粉体对应元件对甲醛、乙酸、甲苯、乙醇、丙酮、三甲胺等六种气体的气敏性能.结果表明:通过溶剂热法制备的ZnO粉体为纳米棒状结构,棒长度和直径随Cu2+掺杂比例不同发生变化;3mol%Cu2+掺杂ZnO(120℃,10h)样品对应元件对低浓度乙醇有很好的选择性,在395℃工作温度下对1×10–3乙醇的灵敏度为380.5,响应和脱附时间分别为5 s和40 s,对1×10–6乙醇的灵敏度可达4.2. 相似文献
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为了提高ZnSnO3的氢敏性能,以共沉淀法制备ZnSnO3并对其进行了贵金属Pd2+掺杂.采用X射线衍射仪(X-ray diffraction,XRD)及透射电镜(transmission electron microscopy,TEM)对制备的气敏材料进行结构及形貌表征,并使用静态配气法测试了掺杂前后ZnSnO3的氢敏性能.结果表明:掺杂Pd2+可显著提高ZnSnO3的氢敏性能.在工作温度为240℃、浓度为300×10-6的条件下,Pd2+掺杂纳米ZnSnO3对氢气的灵敏度为12,是未掺杂时的3倍.基于第一性原理探讨气敏机理,计算结果表明:Pd2+掺杂改变了ZnSnO3能带间的电子运动状态,使ZnSnO3费米能级由0.725 eV移动到1.035 eV,在费米能级附近产生新的电子峰,使其电导性能在气敏反应过程中改变更为明显.Pd2+掺杂还使ZnSnO3表面吸附氧的能力显著增加,对提高氢敏性能起到了关键作用. 相似文献
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采用低温固相化学反应法制备了Pr2O3掺杂的ZnO纳米复合粉体, 并用此粉体在不同烧结温度下制备了高压ZnO压敏电阻。采用X射线衍射、 比表面测试、 透射电镜、 扫描电镜等手段对制备的ZnO纳米复合粉体及高压ZnO压敏电阻进行了表征, 并与未掺杂ZnO压敏电阻进行了对比研究, 探讨了稀土氧化物Pr2O3掺杂对高压ZnO压敏电阻电性能的影响机制。结果表明: 较低的烧结温度(1030~1130 ℃)时, 掺杂的稀土氧化物Pr2O3偏析于ZnO晶界中, 有活化晶界、 促使晶粒生长的作用; 同时, Pr2O3掺杂导致1080 ℃烧结的ZnO压敏陶瓷体中晶体相互交织形成晶界织构, 比未掺杂的更均匀和致密, 这有助于高压ZnO压敏电阻晶界性能的改善, 从而提高其综合电性能。当烧结温度为1080 ℃时, Pr2O3掺杂的高压ZnO压敏电阻的综合电性能最佳: 电位梯度为864.39 V/mm, 非线性系数为28.75, 漏电流为35 μA。 相似文献
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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. 相似文献
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Europium doped ZnO nanopowders made by microwave hydrothermal method are investigated. As zinc oxide precursor zinc nitrate(V) hexahydrate (Zn(NO3)2·6H2O) was used. Two types of nanopowder samples are examined: as grown and annealed at 750 °C in air atmosphere. We investigate the structural, morphological and optical prosperities of europium doped ZnO. Results of scanning electron microscopy, X-ray diffraction, photo- and cathodoluminescence investigations and also CIE1961 chromaticity diagram are presented. 相似文献
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Pure ZnO:Eu3+ nanoparticles (~ 50 nm) were prepared by a solution combustion method. ZnO and Eu2O3 were used as starting materials and dissolved in nitric acid. Citric acid was used as a fuel. The reaction mixture was heated at 350 °C resulting into a rapid exothermic reaction yielding pure nanopowders. The atomic weight concentration of Eu3+ doped in ZnO was 20%. Transmission electron microscopy (TEM) was used to study the particle size and morphology. The nanopowders were characterized for phase composition using X-ray diffractrometry (XRD). Particle size distribution (PSD) analysis of ZnO: Eu3+ showed particle sizes ranging from 30 to 80 nm.The photoluminescence emission spectra of ZnO:Eu3+ nanostructures showed a strong band emission around 618 nm when excited with 515 nm wavelength. 相似文献
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K. Vijayalakshmi K. Karthick 《Journal of Materials Science: Materials in Electronics》2013,24(6):2067-2071
In this paper, we report the synthesis of nano-structured Zinc Oxide (ZnO) and Magnesium doped Zinc Oxide (ZnO:Mg) using air stable and inexpensive chemicals, by microwave assisted processing. The as-synthesized ZnO and ZnO:Mg nanopowders were annealed at 800 °C for 1 h. The samples were further characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and room temperature photoluminescence (PL) spectra. The crystallite size of ZnO decreased from 24 to 16 nm, and the intensity of most prominent vibration band of ZnO becomes weak when Mg dopant is added. SEM images of Mg doped ZnO showed clearly distinct hexagonal shaped nanoparticles with good crystalline quality and size contrast to ZnO. The PL result indicate that the ZnO exhibit strong and sharp UV emission peak at 380 nm. Our result showed that, by doping magnesium into ZnO, the UV emission peak shift towards the lower wavelength at ~370 nm with increasing intensity, which may be attributed to the size confinement. From this study, the microwave processing method has been proved to be successful for preparing other metal oxide nanopowders with good crystal quality. 相似文献
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S. Kumaresan K. Vallalperuman S. Sathishkumar M. Karthik P. SivaKarthik 《Journal of Materials Science: Materials in Electronics》2017,28(13):9199-9205
Here we report, copper (Cu) and Aluminum (Al) doped zinc oxide (ZnO) nanoparticles by a novel one step microwave irradiation method for the first time. Powder X-ray diffraction (XRD) reveals that both pure and doped samples assigned to hexagonal wurtzite type structure. The calculated average crystalline size decreases from 24 to 11 nm for pure and doped (Al and Cu) ZnO respectively, which is in good agreement with the particles size observed from Transmission Electron Microscope (TEM) analyses. A considerable red shift in the absorption edge and the reduction in the energy gap from 3.35 to 2.95 eV reveal the substitution of Al3+ and Cu2+ ions into the ZnO lattice analyzed by UV–Vis transmission spectra. The photocatalytic degradation of Methyl Violet (MV), Phenol and Rhodamine B (RHB) was investigated by using pure, Al and Cu doped ZnO catalyst under UV light irradiation. The results showed that the photocatalytic property is significantly improved by Cu doping concentration. This could be attributed to extended visible light absorption, inhibition of the electronehole pair’s recombination and enhanced adsorptivity of dye molecule on the surface of Cu–ZnO nanopowders. The samples were further characterized by photoluminescence spectra and Fourier Infrared Spectra (FTIR) analysis. 相似文献
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Fe2O3/TiO2和ZnO/TiO3纳米颗粒薄膜的亲水性能和光催化性能的研究 总被引:7,自引:1,他引:6
采用溶胶—凝胶法在玻璃上制备了锐钛矿型TiO2和过渡金属铁、锌离子掺杂的TiO2薄膜,并通过XRD、XPS、AFM表征了合成的薄膜.结果表明铁和锌离子掺入后,TiO2薄膜变的更加致密.铁离子和锌离子分别以Fe2O3和ZnO的形式存在.在紫外光照射下,TiO2薄膜表现明显的亲水性.金属离子掺杂的TiO2薄膜,亲水性能明显增强.铁离子掺入对光催化降解甲基橙有一定的抑制作用;少量的锌离子掺入对光催化降解甲基橙有促进作用,锌离子掺入量增大后,效果并不明显. 相似文献
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采用溶胶一凝胶法制备了稀土铈掺杂钛酸钡纳米晶粉体,借助XRD、Raman、SEM以及矢量网络分析仪等分析测试手段对样品晶相、晶格常数、粒径、表面形貌及微波吸收特性进行了研究.结果表明:铈掺杂样品均形成四方相钛酸钡微晶,晶粒发育良好.随着铈掺杂量增大,晶粒逐渐细化,晶格常数a变大,晶格常数c减小;与未掺杂钛酸钡相比,在2-18GHz频率范围内,稀土铈掺杂材料(掺杂量0.2%)的反射损耗明显地提高,反射峰发生蓝移,尤其5.8GHz和7GHz处反射损耗分别提高了15dB和30dB,频带拓宽近2倍.由此可见铈掺杂有利于改善钛酸钡材料的微波吸收特性. 相似文献
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Yulong Zhang Ye Yang Junhua Zhao Ruiqin Tan Weiyan Wang Ping Cui Weijie Song 《Journal of Materials Science》2011,46(3):774-780
Aluminum-doped zinc oxide nanopowders were prepared using a surfactant assisted complex sol–gel method, and were characterized
using inductively coupled plasma, X-ray diffraction, scanning electron microscopy/energy dispersive X-ray spectroscopy, X-ray
photoelectron spectroscopy, and UV–Vis spectroscopy. Al was effectively doped into the ZnO matrix with concentrations up to
6.00 atomic ratio percents (at.%). X-ray diffraction results revealed that all of the nanoparticles had a pure hexagonal wurtzite
structure free of any impurities when annealing temperature was below 1273 K. The optical band gap of the nanopowders, which
was affected by the Al-doping concentration, reached a maximum of 3.43 eV when ZnO was doped with 4.00 at.% Al. The effect
of post-annealing temperature and vacuum conditions on the resistivities of the Al-doped ZnO nanoparticles was also investigated.
And the lowest volume resistivity (1.2 Ω cm) was achieved by annealing the Al-doped ZnO nanoparticles in a vacuum at 1173 K
for 2 h. 相似文献