Russ Tamara, Hu Zhixiang, Li Long, Zhou Licheng, Liu Huan, Weimar Udo, Barsan Nicolae
Institute of Physical and Theoretical Chemistry (IPTC) and Center of Light-Matter Interaction, Sensors and Analytics (LISA+), University of Tuebingen, D-72076Tuebingen, Germany.
School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan430074, P. R. China.
ACS Sens. 2022 Oct 28;7(10):3023-3031. doi: 10.1021/acssensors.2c01319. Epub 2022 Oct 6.
The demand for gas sensors that can detect gases selectively at low temperatures has increased steadily over recent years. Most devices use semiconducting metal oxides as sensing materials which often require high operation temperatures and suffer from a lack of selectivity. Semiconducting metal sulfides were found to be a reasonable alternative for the application in sensing devices at low temperatures. Since metal sulfides are a relatively new class of materials applied in gas sensors, there is little work on sensing mechanisms and overall sensing characteristics of these materials. In this work, the authors investigated the sensing performance of BiS nanorods operated at 50 °C in the presence of several target gases and found a selective response to oxidizing gases. With the help of DC resistance measurements, diffuse reflectance infrared Fourier transform spectroscopy and work function measurements in a Kelvin Probe setup, the NO and O sensing mechanisms of BiS nanorods were revealed. While initially sulfur vacancies were the predominant reaction sites, the formation of nitrates became the key reaction in higher NO concentrations. Additionally, it was found that the reaction with O healed sulfur vacancies effectively inhibiting the reaction with NO.
近年来，对能够在低温下选择性检测气体的气体传感器的需求稳步增长。大多数器件使用半导体金属氧化物作为传感材料，这些材料通常需要较高的工作温度，并且选择性不足。人们发现半导体金属硫化物是低温传感器件应用的合理替代材料。由于金属硫化物是应用于气体传感器的一类相对较新的材料，关于这些材料的传感机制和整体传感特性的研究很少。在这项工作中，作者研究了在50℃下在几种目标气体存在下操作的BiS纳米棒的传感性能，并发现对氧化性气体有选择性响应。借助直流电阻测量、漫反射红外傅里叶变换光谱和开尔文探针装置中的功函数测量，揭示了BiS纳米棒的NO和O传感机制。虽然最初硫空位是主要的反应位点，但在较高的NO浓度下，硝酸盐的形成成为关键反应。此外，还发现与O的反应修复了硫空位，有效地抑制了与NO的反应。
