纺锤状氧化锌的制备及气敏性能研究

以硝酸锌和氢氧化钾为原料,采用传统的溶剂热法于150℃时合成了纺锤状氧化锌粉体,通过X射线衍射仪(XRD)和扫描电镜(SEM)及红外光谱仪(IR)对产物的物相、微观形貌及化学键进行了分析,结果表明,产物属于六方晶系纤锌矿结构的ZnO,结晶良好,呈规则的纺锤状,尺寸比较均一,长约20μm,利用该粉体制成厚膜型气敏原件,并用静态配气法测试其气敏性能,测试结果表明,纺锤状氧化锌在加热温度为220℃时对乙醇和丙酮气体具有很好的气敏性能,且具有很低的检测极限和极短的响应时间。     

类积木状ZnO气体传感器的制备及其气敏特性研究

采用水热法合成了类积木状ZnO纳米结构,利用X射线衍射仪(XRD)、X射线能谱分析仪(EDS)和扫描电子显微镜(SEM)对制备的ZnO纳米结构的物相、化学组分及微观形貌进行了表征与分析。对基于ZnO纳米结构的气体传感器进行甲烷气敏特性测试,测试结果表明:该传感器的最佳工作电压为5 V,在该电压下对体积分数为200×10-6甲烷气体的灵敏度可高达55.4%,最低检测限为1×10-6。     

PdO修饰的SnO2纳米球的制备及其气敏特性研究

通过溶剂热法和退火处理制备了不同浓度(0 mol％,2 mol％,5 mol％,10 mol％)PdO修饰的SnO2纳米球.采用X射线衍射仪(XRD)、X射线能谱分析仪(EDS)和扫描电子显微镜(SEM)等测试手段对材料的物相、元素种类和形貌进行了表征,并制成气敏元件,对氢气(H2)进行气敏测试.实验结果表明:5 mol％PdO修饰的SnO2纳米球气体传感器最佳工作温度为175℃,其对100×10-6氢气灵敏度达到19,是纯的SnO2纳米球的灵敏度的3倍.最后,对PdO修饰氧化锡纳米球气体传感器气敏机理进行了分析讨论.     

Pr6O11/SnO2复合材料的制备及对异丙醇气敏特性的研究

通过水热法和退火处理制备了不同Pr浓度(0%,1%,2%,4%)的Pr6O11/SnO2复合材料。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)等方法对制备材料的物相结构、微观形貌和元素组成进行了表征,并制成旁热式气敏元件,对异丙醇气体进行气敏测试。实验结果表明,基于2%样品的Pr6O11/SnO2气体传感器的气敏性能最佳,在最佳工作温度200℃下对100×10^-6异丙醇气体响应达到16.2,是纯相SnO2传感器响应的2.3倍。最后,对基于Pr6O11/SnO2复合材料气体传感器的气敏机理进行了分析讨论。     

花状WO3纳米结构的水热合成及其甲醛气敏研究

采用中温水热法合成了三维花状WO3纳米结构,通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)对样品的物相成分及微观形貌进行了表征。同时基于合成的花状WO3纳米材料制备了气敏元件,测试了其在200℃的最佳工作温度下,对体积分数为40×10^-6的HCHO气体的气敏性能。结果表明,该气敏元件对HCHO气体有优异的选择性及稳定性,同时对HCHO气体灵敏度可达18.57。     

射频磁控溅射SnO2/MWCNTs 薄膜材料的气敏性能研究

采用射频反应磁控溅射方法制备掺杂多壁碳纳米管(MWCNTs)的snO2薄膜材料,并在此基础之上制作了N02气敏传感器,使用扫描电子显微镜(SEM)和X射线衍射仪(XRD)研究了SnO2/MWCNTs薄膜材料的表面形貌、物质组份材料特性,采用气敏元件测试系统来分析优越感的气敏效应,包括灵敏度、选择性、响应-恢复等特性,实验结果表明该气敏传感器对超低浓度(10ppb)NO2气体有很好的灵敏度,对干扰气体不敏感,提出了气敏机理解释实验现象.     

Pt掺杂ZnFe2O4纳米颗粒的制备及气敏性能研究

本文通过液相法合成了Pt掺杂ZnFe2o4纳米颗粒,利用X射线衍射仪(XRD)、场发射扫描电镜(FESEM)、Ｘ射线光电子能谱(XPS)等手段对材料结构、形貌等进行表征,并将其制成厚膜型气敏元件,探讨烧结温度、掺杂量及工作温度对其气敏性能的影响。结果表明:Pt掺杂未改变ZnFe2o4的尖晶石结构,600℃烧结,2%ZnFe2o4掺杂ZnFe2o4气敏元件在 150℃的工作温度下对1X10-4(V/V0)的H2S气体灵敏度达144.11,在此工作温度下对1X10-6(V/V0) ~ 1X10-3(V/V0)H2S气体均有较好的响应－恢复特性。     

氧等离子体处理ZnO纳米纤维材料的制备及其对丙酮气敏性能的研究

采用静电纺丝法制备了ZnO纳米纤维材料并使用氧等离子体对其进行表面处理.通过X射线衍射(XRD),扫描电子显微镜(SEM),BET比表面积测试以及X射线光电子能谱分析(XPS)等手段对样品的结构与形貌进行了表征分析.将氧等离子体处理前后的ZnO纳米纤维分别制成气体传感器,对浓度为1×10-6~100×10-6(体积分数)丙酮气体的敏感特性进行了测试分析.测试结果表明,氧等离子体处理后的ZnO纳米纤维响应值较未处理的ZnO纳米纤维有大幅度的提升,最佳工作温度也有所降低,且对甲醛、苯、甲苯、二甲苯等几种干扰气体表现出更好的选择性.从晶粒间势垒和耗尽层厚度等角度初步分析了氧等离子体处理改善ZnO气敏特性的机理.     

NiO/SnO2纳米复合粉体的制备及其气敏性能的研究

利用化学共沉淀法制备出NiO掺杂SnO2复合粉体,用X射线衍射仪(XRD),透射电镜(TEM),扫描电镜(SEM)对样品的组成、粒径、形貌进行了表征,并对样品的气敏性能进行了测试,结果表明:该复合粉体对甲醛的灵敏度较好,并在工作温度为95℃时对乙醇有较好的选择性.     

孪连柱状ZnO的水热合成及其气敏性能研究

采用水热法合成了孪连柱状ZnO纳米粉体,通过X射线衍射仪(XRD)、扫描电镜(SEM)、红外光谱仪(IR)和X-射线光电子能谱仪(XPS)等对产物的物相、微观形貌、表面化学键及化学组分进行了表征与分析,并用静态配气法测试了其厚膜型元件的气敏性质,结果表明,产物属于纤锌矿型六方晶系的ZnO,平均直径约300 nm,长约500 nm,其厚膜型元件在工作温度为395℃时对体积分数为100×10-6乙醇和丙酮气体能快速响应,灵敏度分别达到了14.4和29.4,特别是对丙酮气体具有较好的选择性。     

Light induced enhancing gas sensitivity of copper-doped zinc oxide at room temperature

Copper-doped zinc oxide (ZnO) (1 mol%) nanocrystals were synthesized using a sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), inductive coupled plasma with optical emission spectrometry (ICP-OES). The XRD result indicated that the introduction of copper had no influence on the crystal structure of ZnO, though ICP-OES exhibited the molar ratio of copper and zinc was 0.86:100. The gas response of the copper-doped ZnO was also studied to ethanol and acetone without and with the illumination of 355 nm light. It was found that the ultraviolet light irradiation could enhance the gas response, and the mechanism with irradiation was discussed. Our results demonstrated that light irradiation was a promising approach to achieve large response at room temperature.     

Pd掺杂ZnO纳米线的乙醇气敏特性研究

研究以贵金属Pd作为掺杂剂的ZnO纳米线敏感元件的乙醇气敏性能。采用水热法在叉指电极上直接制备出具有c轴取向的ZnO多晶纳米线。用SEM,XRD和EDS分析手段观测了材料的微观结构,并对其乙醇气敏性能进行了测试。实验结果表明:对于体积分数为200×10-6的乙醇气体,Pd掺杂的ZnO纳米线在灵敏度(8.17)、工作温度(325℃)和响应恢复时间(15,8s)上优于纯的ZnO纳米线。最后,对Pd掺杂的气敏机理进行了讨论。     

Hydrothermal synthesis and gas sensing characters of ZnO nanorods

ZnO nanorods are prepared by a hydrothermal process with cetyltrimethylammonium bromide (CTAB) and zinc powder at 182 °C. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The gas sensing properties of the materials have been investigated. The results indicate that the as-prepared ZnO nanorods show much better sensitivity and stability than the conventional materials. The PdO doping can improve the sensitivity and selectivity of the sensors. ZnO nanorods are excellent potential candidates for gas sensors.     

Selective detection of HCHO gas using mixed oxides of ZnO/ZnSnO3

Mixed oxides of ZnO/ZnSnO₃ doped with Au element were prepared by a hydrothermal process. The crystal structure, composition and ceramic microstructure of the powders obtained were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that the product is the mixture of ZnO/ZnSnO₃; its particle size is about 500 nm with good dispersivity in shape. The sensitivity, selectivity, response and recovery properties of the ZnO/ZnSnO₃-based sensors were investigated by mixing a target gas in air. It is found that the sensors have remarkable sensitivity to HCHO vapor and satisfactory selectivity to other gases.     

表面改性四针状纳米ZnO结构与气敏性能研究

将4种质量分数(5%,10%,20%,30%)的Co(CH3COO)24H2O混合到四针状纳米ZnO原料里,采用超声化学浸泡法制备出表面改性四针状纳米ZnO颗粒。通过XRD和TEM分析了表面改性四针状纳米ZnO结构的物相和形貌特征。随着Co(CH3COO)24H2O质量分数增大,Co3O4相明显出现,Co3O4相沉积在ZnO表面上。研究表明:以表面改性四针状纳米ZnO粉末为原料制备的厚膜气敏元件,与纯ZnO气敏元件相比,Co(CH3COO)24H2O质量分数为5%的气敏元件对酒精和甲醇有较高的灵敏度,并讨论了表面改性对气敏性能的影响。     

基于微接触印刷的ZnO紫外传感器特性研究

采用微接触印刷技术和水热生长方法在硅基底上实现了ZnO种子层的图案化转移与纳米线阵列的可控制备。利用X射线衍射(XRD)、能量色散谱(EDS)和扫描电子显微镜(SEM)等测试手段对制备的ZnO纳米线晶体结构、化学组分以及表面形貌进行了表征,并对制备的ZnO纳米线传感器进行了紫外特性测试。测试结果表明:随着紫外光强度的增加,传感器的光暗电流比和光响应度也随之增加。当紫外传感器偏压在4.5 V时,其光暗电流比为80.8,响应度可达4.05 A/W。     

EPR and DRS evidence for NO2 sensing in Al-doped ZnO

Zinc oxide (ZnO) is a well-known semiconducting multifunctional material wherein properties right from the morphology to gas sensitivity can be tailor-made by doping or surface modification. Aluminum (Al)-incorporated porous zinc oxide (Al:ZnO) exhibits good response towards NO₂ at low-operating temperature. The NO₂ gas concentration as low as 20 ppm exhibits S = 17% for 5 wt.% Al-incorporated ZnO. The NO₂ response increases with operating temperature and concentration and reaches to its maximum at 300 °C without any interference from other gases such as SO₃, HCl, LPG and alcohol. Physico-chemical characterization likes differential thermogravimetric analysis (TG-DTA) electron paramagnetic resonance (EPR) and diffused reflectance spectroscopy (DRS) have been used to understand the sensing behavior for pure and Al-incorporated ZnO. The TG-DTA depicts formation of ZnO phase at 287 °C. The EPR study reveals distinct variation for O⁻ (g = 2.003) and Zn interstitial (g = 1.98) defect sites in pure and Al:ZnO. The DRS studies elucidate signature of adsorbed NO_x species in aluminium-incorporated zinc oxide indicating its tendency to adsorb these species even at low temperatures. This paper is an attempt to correlate the gas sensing behavior with the physico-chemical studies such as EPR and DRS.     

Fabrication of gas sensing devices with ZnO nanostructure by the low-temperature oxidation of zinc particles

A method for low-temperature synthesis of a mixture of high-density ZnO nanoflakes and nanowires was developed to produce low-cost and high-efficiency gas sensors with ZnO nanostructures. ZnO nanoflakes and nanowires were grown on glass substrates by the RF sputter deposition of Zn particles and localized oxidation at a low temperature of 300 °C. The synthesized ZnO nanoflakes and nanowires were polycrystalline and had nanometer dimensions, as revealed by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) measuring. A gas sensor based on the mixture of ZnO nanoflakes/nanowires responded rapidly and sensitively to ethanol. The sensing properties of the ZnO nanostructure sensor were approximately 72% for 50 ppm ethanol gas at an operating temperature of 100 °C. The response to 10 ppm of ethanol gas was 42% at the same temperature.     

硅基底和金刚石基底上沉积ZnO薄膜工艺研究

采用射频磁控溅射方法分别在硅基底和金刚石基底上制备ZnO薄膜,研究了硅和金刚石衬底的不同对ZnO薄膜生长机理的影响,同时分析了氩氧比和退火温度这两个工艺参数对薄膜的晶格取向和表面形貌的影响。利用XRD和AFM对ZnO压电薄膜的性能进行了测试。结果显示,金刚石基片上制备的薄膜表面状态远优于硅基片上的薄膜表面状态;在同类型基底上生长的ZnO薄膜,薄膜的晶格取向随着氩氧比的升高而增强;对于硅基底上生长的ZnO薄膜,适当的退火能够成倍地提高薄膜的c轴取向性。