Gas Sensors: Ultrasensitive and Highly Selective Gas Sensors Based on Electrospun SnO2 Nanofibers Modified by Pd Loading (Adv. Funct. Mater. 24/2010)

This work presents a new route to suppress grain growth and tune the sensitivity and selectivity of nanocrystalline SnO₂ fibers. Unloaded and Pd‐loaded SnO₂ nanofiber mats are synthesized by electrospinning followed by hot‐pressing at 80 °C and calcination at 450 or 600 °C. The chemical composition and microstructure evolution as a function of Pd‐loading and calcination temperature are examined using EDS, XPS, XRD, SEM, and HRTEM. Highly porous fibrillar morphology with nanocrystalline fibers comprising SnO₂ crystallites decorated with tiny PdO crystallites is observed. The grain size of the SnO₂ crystallites in the layers that are calcined at 600 °C decreases with increasing Pd concentration from about 15 nm in the unloaded specimen to about 7 nm in the 40 mol% Pd‐loaded specimen, indicating that Pd‐loading could effectively suppress the SnO₂ grain growth during the calcination step. The Pd‐loaded SnO₂ sensors have 4 orders of magnitude higher resistivity and exhibit significantly enhanced sensitivity to H₂ and lower sensitivity to NO₂ compared to their unloaded counterparts. These observations are attributed to enhanced electron depletion at the surface of the PdO‐decorated SnO₂ crystallites and catalytic effect of PdO in promoting the oxidation of H₂ into H₂O. These phenomena appear to have a much larger effect on the sensitivity of the Pd‐loaded sensors than the reduction in grain size.     

Low‐Dimensional Transition Metal Dichalcogenide Nanostructures Based Sensors

Two‐dimensional (2D) transition metal dichalcogenides (TMDs) nanostructures have been widely applied in environmental and biological analysis, biomedicine, electronic devices, and hydrogen evolution catalysis. Meanwhile, this excitement in 2D TMDs has spilled over to their counterparts of different dimensionalities like one‐dimensional (1D) and zero‐dimensional (0D) TMDs nanostructures. Eventual physical and chemical properties of TMDs nanostructures still remain to be highly dependent on their dimensionalities and size scale, and recently creatively exploring these physical and chemical properties is extremely impactful for the sensing field of TMD nanomaterials. Herein, we review a wide range of sensing applications based on not only graphene‐like 2D TMDs nanostructures but also the rapidly emerging subclasses of 1D, and 0D TMDs nanostructures. Their unique and interesting structures, excellent properties, and valid preparation methods are also included and the analytical objectives, ranging from heavy metal ions to small molecules, from DNA to proteins, from liquids to even vapors, can be met with extremely high selectivity and sensitivity. We have also analyzed our current understanding of 0D and 1D TMDs nanostructures and learning from graphene with the goal of contributing fresh ideas to the overall development of more advanced future TMDs based sensors.     

Self‐Recovering Triboelectric Nanogenerator as Active Multifunctional Sensors

A novel self‐recovering triboelectric nanogenerator (STENG) driven by airflow is designed as active multifunctional sensors. A spring is assembled into the STENG and enables the nanogenerator to have self‐recovering characteristic. The maximum output voltage and current of the STENG is about 251 V and 56 μA, respectively, corresponding to an output power of 3.1 mW. The STENG can act as an active multifunctional sensors that includes a humidity sensor, airflow rate sensor, and motion sensor. The STENG‐based humidity sensor has a wide detection range of 20%–100%, rapid response time of 18 ms, and recovery time of 80 ms. Besides, the STENG could be utilized in the application of security monitoring. This work expands practical applications of triboelectric nanogenerators as active sensors with advantages of simple fabrication and low cost.     

传感器

能滤除假回波的超声液位计；能测量多种气体的瞬态分析仪；通孔式加速度计；法兰安装式扭矩变送器；基于微处理器的指示器／调节器。     

传感器

硫化氯分析仪;防堵塞型液位计;区域视觉传感器;带数字编程功能的超声传感器;基于USB接口的倾角传感器。[编者按]     

传感器

不含聚氯乙烯的温度传感器M3000系列温度传感器采用不含聚氯乙烯的电缆,此电缆不含卤化物及对环境有害的增塑剂或含有重金属的稳定剂。此新款温度传感器延续了其前身产品M2000系列的成功,在温度循环试验中,     

传感器

连续式液位传感器UCL-520系列UCL-520型系列连续式超声波水位传感器可用于处理非接触式应用,例如工业水处理、废水管理以及化学制品储存。使用两线超声波变送器,提供高达8m的量距,这些传感器集成了坚固的PVDF换能器,可用于超纯、腐蚀性或