Yin Xi-Tao, Li Jing, Wang Qi, Dastan Davoud, Shi Zhi-Cheng, Alharbi Najlaa, Garmestani Hamid, Tan Xiao-Ming, Liu Ying, Ma Xiao-Guang
School of Physics and Optoelectronic Engineering, Ludong University, Yantai, Shandong Province 264000, China.
The Key Laboratory of Chemical Metallurgy Engineering of Liaoning Province and School of Materials and Metallurgy, University of Science and Technology Liaoning, Anshan, Liaoning Province 114051, China.
Langmuir. 2021 Nov 23;37(46):13548-13558. doi: 10.1021/acs.langmuir.1c01706. Epub 2021 Nov 12.
Metal oxide semiconductor (MOS) gas sensors show poor selectivity when exposed to mixed gases. This is a challenge in gas sensors and limits their wide applications. There is no efficient way to detect a specific gas when two homogeneous gases are concurrently exposed to sensing materials. The p-n nanojunction of SnO-CrO nanocomposites (NCs) are prepared and used as sensing materials (/ shows the Sn/Cr molar ratio in the SnO-CrO composite and is marked as SnCr for simplicity). The gas sensing properties, crystal structure, morphology, and chemical states are characterized by employing an electrochemical workstation, an X-ray diffractometer, a transmission electron microscope, and an X-ray photoelectron spectrometer, respectively. The gas sensing results indicate that SnCr NCs with / greater than 0.07 demonstrate a p-type behavior to both CO and H, whereas the SnCr NCs with / < 0.07 illustrate an n-type behavior to the aforementioned reduced gases. Interestingly, the SnCr NCs with / = 0.07 show an n-type behavior to H but a p-type to CO. The effect of the operating temperature on the opposite sensing response of the fabricated sensors has been investigated. Most importantly, the mechanism of selectivity opposite sensing response is proposed using the aforementioned characterization techniques. This paper proposes a promising strategy to overcome the drawback of low selectivity of this type of sensor.
金属氧化物半导体（MOS）气体传感器在暴露于混合气体时表现出较差的选择性。这是气体传感器领域面临的一个挑战，限制了它们的广泛应用。当两种同类气体同时作用于传感材料时，没有有效的方法来检测特定的气体。制备了SnO-CrO纳米复合材料（NCs）的p-n纳米结，并将其用作传感材料（/表示SnO-CrO复合材料中的Sn/Cr摩尔比，为简便起见标记为SnCr）。分别采用电化学工作站、X射线衍射仪、透射电子显微镜和X射线光电子能谱对其气敏性能、晶体结构、形貌和化学状态进行了表征。气敏结果表明，/大于0.07的SnCr NCs对CO和H均表现出p型行为，而/ < 0.07的SnCr NCs对上述还原性气体表现出n型行为。有趣的是，/ = 0.07的SnCr NCs对H表现出n型行为，对CO表现出p型行为。研究了工作温度对所制备传感器相反传感响应的影响。最重要的是，利用上述表征技术提出了选择性相反传感响应的机制。本文提出了一种有前景的策略来克服这类传感器选择性低的缺点。
