Si-Cu nanocomposite as an effective sensing layer for H2S based on quartz surface acoustic wave sensors

• Published in: Sensors and actuators. A. Physical. 2023-04, Vol.353, p.114225, Article 114225
• Main Authors: Che, Jian, Wang, Junsen, Qiao, Changcang, Xia, Yudong, Ou, Kai, Zhou, Jing, Ni, Yuxiang, Zhang, Wenting, Han, Yuchen, Zu, Xiaotao, Fu, Yongqing, Tang, Yongliang
• Format: Article
• Language: English
• Subjects: CuO; Gas sensor; H2S; Humidity; Surface acoustic wave
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2023.114225

It has been a critical challenge to develop highly sensitive H2S gas sensors, due to its wide-range application in industry and frequent leakage, which endangers people's lives. In this work, a highly sensitive room-temperature SAW H2S gas sensor based on Si-Cu nanocomposite was developed. The Cu content in this composite layer plays a key role for H2S response of the sensor because CuO, an excellent adsorption site for H2S, presents on the surface of Cu. The amorphous Si content results in the highly porous structure enhancing the interaction between CuO and H2S. The interaction leads to the formation of CuS and a negative frequency response of the sensor. H2O molecules effectively participate the reactions between CuO and H2S, and the responses of H2S were significantly enhanced in a moister environment. With the relative humidity of 60 %, the sensor can detect 50 ppb H2S with a response of − 225 Hz. [Display omitted] •The surface CuO in the composite adsorbs and reacts with H2S and then form CuS.•The formation of CuS lead to the negative frequency responses of the SAW sensors.•The sensing performance of the senor toward H2S is critically influenced by H2O.•The SAW sensor can precisely detect H2S gas ranging from 50 ppb to16 ppm.