二氧化锡纳米粉料的制备及其气敏性能

采用低温等离子体法以无水四氯化锡为源物质制备了二氧化锡超微粉料,TEM照片显示粉料粒度均匀,粒径为10nm量级,并且阴极高压越高,粒径越小。用该粉料制备的气敏元件,测定了气体灵敏度与温度及浓度的关系,显示了比一般无渗杂氧化锡元件灵敏度高的特点,可望开发成为广普型气敏传感器。还讨论了元件的灵敏度和电导温度特性随不同热处理温度的变化。大的比表面积在这种类型传感器运行机制中起着重要作用.     

石墨烯/聚赖氨酸修饰玻碳电极测定铅离子

通过聚赖氨酸修饰电极静电吸附氧化石墨烯,并结合电化学还原制备石墨烯/聚赖氨酸修饰玻碳电极。应用Raman光谱确认了通过电化学还原过程可将电极表面所吸附的氧化石墨烯部分地还原成石墨烯。在阳极溶出法测定Pb2+的应用中,所得到的石墨烯/聚赖氨酸修饰玻碳电极较裸玻碳电极表现出较高的响应灵敏度。在1.0～5.0×10-6mol/L浓度范围,响应峰电流与Pb2+浓度呈良好的线性关系。     

石墨烯/δ-MnO2复合材料及其超级电容器性能研究

文章采用共同沉积法制备石墨烯/MnO2复合材料,研究五种不同质量比的石墨烯和MnO2对复合材料结构以及超级电容器性能的影响.实验结果显示:复合材料中的MnO2为α型MnO2,其中当石墨烯的质量分数为27.5％时,石墨烯/MnO2复合材料具备较好电容器性能,当使用6mol/L氢氧化钾溶液作为电解质时,石墨烯/MnO2复合...     

石墨烯/MOFs复合材料在电化学生物传感器中的研究与应用

金属—有机骨架(MOFs)材料是由金属离子或离子簇与多位有机配体通过化学键合自组装产生的多孔配位聚合物(PCP).基于其高比表面积、可调节的孔径、良好的热稳定性,以及多孔、微晶粉末结构、易于裁剪等特性,被广泛应用于电化学生物传感器领域.MOFs与纳米材料结合,产生的MOFs复合材料,具有更好的机械稳定性、电导率和催化性...     

纳米银/石墨烯电化学传感器的制备及应用研究

以硝酸银和氧化石墨为原料,采用硼氢化钠还原法制备了纳米银/石墨烯纳米复合材料(Nano-Ag/ERGO),并采用紫外-可见吸收光谱法、X-射线粉末衍射法及红外光谱法进行表征.采用滴涂法制备了纳米银/石墨烯复合纳米材料修饰的玻碳电极(Nano-Ag/ERGO/GCE).研究了过氧化氢(H2O2)在制备的修饰电极上的电化学行为.结果表明:采用一步还原法制备石墨烯支持银纳米粒子,具有制备方法简单且纳米粒子粒径可控等优点,对H2O2的电还原具有极强的催化活性.研究成果在实际样品的H2O2快速检测中具有潜在的应用价值.     

石墨烯/Fe3O4/壳聚糖修饰电极对镉离子的检测研究

镉污染问题严重威胁人类生命健康,因此对镉离子(Cd2+)的快速且高灵敏度检测至关重要.本文通过滴涂法制备了石墨烯/四氧化三铁/壳聚糖/复合膜修饰玻碳电极(GR/Fe3 O4/CS/GCE),采用方波溶出伏安法探讨此修饰电极对Cd2+的溶出伏安响应,优化了电解质、pH值、沉积电位、沉积时间等条件.在最佳条件下,Cd2+的...     

基于Pt/石墨烯纳米复合材料的甲醛电化学传感器

采用电沉积的方法制备了Pt/石墨烯纳米复合材料,考察了该复合材料的电化学性能,用于甲醛的检测,表现出良好的检测性能.实验结果表明:在0. 1 mol/L的H2 SO4 溶液中,Pt/石墨烯纳米复合材料修饰电极可以实现在2 ×10 -6 ~2 ×10-3 mol/L浓度范围内甲醛浓度的检测,最低检测限为1 ×10-6 mol/L,并且具有高的灵敏度和良好的重现性.     

高热导率的聚偏氟乙烯/ 石墨烯复合材料

芯片散热问题限制了芯片技术的进一步发展,寻求高热导率的热界面材料成为突破该瓶颈的 重要手段之一。有机-无机复合材料由于其柔软性以及热导率可调控,有望取代常规材料——硅脂,成 为新一代热界面材料。实验上,有机-无机复合材料的制备方法包括物理混合、分相析出和原位氧化。 该文采用物理混合方法制备聚偏氟乙烯/石墨烯复合材料,并使用非稳态测量方法得到其热导率高达 83 W/(m·K)(温度 T＝360 K、体积分数 f＝76 vol%)。此外,复合材料的热导率与填料的体积分数、颗 粒大小形状以及填料与基体之间的相互作用等因素密切相关,利用改进的有效介质理论 Bruggeman 模 型和 Agari 模型来解释复合材料热导率的物理机制时发现,改进的有效介质理论 Bruggeman 模型并不 能很好地解释该复合材料的高热导率。由 Agari 模型可知,当填料含量较高时,填料之间更容易形成 导热通道,从而提高了复合材料的热导率。     

SnO2超微粒薄膜气敏元件的研制与测试

用射频磁控反应溅射法在Si基片上沉积SnO_2超微粒薄膜,溅射过程中适量掺Pd,用IC技术制成气敏元件.实验结果表明:该元件在90℃左右时对氢气有极高的灵敏度,是一种薄膜化、集成化、高选择性的气敏元件.本文介绍薄膜制备、微观结构分析、元件设计及气敏特性测试.     

Ordered mesoporous Pd/SnO2 synthesized by a nanocasting route for high hydrogen sensing performance

Ordered mesoporous SnO₂ and mesoporous Pd/SnO₂ have been successfully synthesized via nanocasting method using the hexagonal mesoporous SBA-15 as template. Two different procedures, impregnation technique and direct synthesis, were utilized for the doping of Pd in the mesoporous SnO₂. The results of small angle X-ray diffraction (SAXD), nitrogen adsorption–desorption and transmission electron microscopy (TEM) demonstrate that the SnO₂ and Pd/SnO₂ display ordered mesoporous structures and high surface areas. Wide angle X-ray diffraction (WAXD) and X-ray photoelectron spectroscopy (XPS) reveal tetragonal structure of SnO₂ and the existence of Pd element. The sensing properties of mesoporous SnO₂ and mesoporous Pd/SnO₂ for H₂ were detected. The sensor utilizing mesoporous Pd/SnO₂ via direct synthesis method exhibits excellent response and recovery behavior and much higher sensitivity to H₂, compared to those using mesoporous SnO₂ and mesoporous Pd/SnO₂ via impregnation technique. It is believed that its high gas sensing performance is derived from the large surface area, high activity and well dispersion of Pd additive, as well as high porosity, which lead to highly effective surface interaction between the target gas molecules and the surface active sites.     

CuO/SnO2 thin film heterostructures as chemical sensors to H2S

CuO/SnO₂ heterostructures as well as SnO₂(CuO) polycrystalline films have been studied for H₂S sensing. Gas sensing properties of these materials have been compared in conditions: 25–300 ppm H₂S in N₂ at 100–250°C. A shorter response time of the heterostructures as compared to that of the SnO₂(CuO) films has been found. It is suggested that the improvement of dynamic sensor properties of SnO₂/CuO heterostructures is caused by the localization of electrical barrier between CuO and SnO₂ layers.     

基于MG811探头的二氧化碳采集系统设计

二氧化碳采集系统以德州仪器公司的MSP430F169为主要控制芯片,采用MG811二氧化碳气体感应探头检测二氧化碳气体浓度。通过HT1621来驱动段式LCD,显示测量的二氧化碳浓度数据,系统外扩M25P80芯片,实现对测量数据的存储,并可通过USB与上位机进行通信。实验证明,该系统设计工作稳定、结构简单、便于携带,有良好的推广前景。     

Microstructure evolution and gas sensitivities of Pd-doped SnO2-based sensor prepared by three different catalyst-addition processes

We have investigated three ways of impregnating PdO on an SnO₂ gas sensor to achieve a simple and reliable sensor-fabrication process. These impregnating processes are: (1) coprecipitation of SnO₂ and Pd compounds in the solution; (2) addition of PdCl₂ to SnO₂ gel, followed by precipitation; and (3) infiltration of PdCl₂ into calcined SnO₂ powder. Processes (1) and (2) introduce Pd into SnO₂ particles before particle growth is completed. The phase and microstructures of particles have been analysed by X-ray diffraction, scanning and transmission electron microscopes, and an energy-dispering X-ray spectroscope. The presence of Pd in the process of SnO₂ precipitation restrains the growth of SnO₂ particles and enhances a uniform distribution of fine PdO powder on the SnO₂ grains. SnO₂ gas sensors have been fabricated and tested for response to CH₄, C₂H₆ and CO. Processes (1) and (2) show many possibilities of improving SnO₂ gas-sensor sensitivity with a simplified fabrication process.     

石墨烯气体传感解吸附特性研究

分析探讨了石墨烯气体解吸附特性与解吸附方法。通过实验分析石墨烯对NO2气体分子的响应时间、气体分子解吸附时间,分析探讨石墨烯的气敏特性。实验表明,石墨烯对NO2气体传感灵敏度高,响应快,但恢复过程缓慢,气体解吸附时间长。分析表明,通过加热的方法、光照的方法可有效减少石墨烯气体解吸附时间,改善解吸附特性。     

二氧化氮化学膜传感器

本文综述了几年二氧化氮气体化学膜传感器的研究进展,从传感器的原理、传感材料、响应性能等方面进行了评述,展望了二氧化氮化学传感器的发展方向。     

Selective detection of ethanol vapor and hydrogen using Cd-doped SnO2-based sensors

The effect of CdO doping on microstructure, conductance and gas-sensing properties of SnO₂-based sensors has been presented in this study. Precursor powders with Cd/Sn molar ratios ranging from 0 to 0.5 were prepared by chemical coprecipitation. X-ray diffraction (XRD) analysis indicates that the solid-state reaction in the CdO–SnO₂ system occurs and -CdSnO₃ with pervoskite structure is formed between 600 and 650°C. CdO doping suppresses SnO₂ crystallite growth effectively which has been confirmed by means of XRD, transmission electron microscopy (TEM) and BET method. The 10 mol% Cd-doped SnO₂-based sensor shows an excellent ethanol-sensing performance, such as high sensitivity (275 for 100 ppm C₂H₅OH), rapid response rate (12 s for 90% response time) and high selectivity over CO, H₂ and i-C₄H₁₀. On the other hand, this sensor has good H₂-sensing properties in the absence of ethanol vapor. The sensor operates at 300°C, the sensitivity to 1000 ppm H₂ is up to 98, but only 16 and 7 for 1000 ppm CO and i-C₄H₁₀, respectively.     

Micrometer-sized nanoporous tin dioxide spheres for gas sensing

We report the synthesis of mesoporous tin dioxide (SnO₂) materials with well-defined particle morphology. The products consist of uniform spheres with a diameter of 5 μm. The spheres are hierarchically porous with two distinct pore modes of 5.0 nm and 52 nm, respectively. This special porosity is the result of a synthesis procedure which involves a ‘hard templating’ (nanocasting) process. The product forms an approximately homogeneous monolayer of spheres on a sensor substrate and shows promising response to methane gas with low cross-sensitivity to water. The structural properties and gas-sensing performance are compared with a mesoporous SnO₂ material without defined morphology, prepared by a ‘soft templating’ procedure.     

CO_2气敏元件特性检测装置

介绍了一种合配气、温控、检气的流通型检测装置，具有简易可行、温度控制精确、能快速进行CO2气体浓度切换等特点，能较好地检测CO2气敏元件的静、动态特性。