Polymer bonded Graphene- LaNiSbWO₄ nanocomposite (G-LaNiSbWO₄-PPy) for CO₂ sensing performance under normal temperature condition

Abstract

Demand for the detection of carbon dioxide (CO₂) is increasing in various fields, including air-quality monitoring, health care, and agriculture. Smart gas sensors, in which micromachined gas sensors are integrated with driving circuits, are desirable for the social development of the internet of things. In this study, CO₂ sensors were fabricated and investigated. The sensors have LaNiSbWO₄-G-PPy (LNSW-G-Ppy) stacked layers as a sensing material in electrodes. A CO₂ response of 1.2 for a CO₂ concentration of 1800 ppm was obtained with a low power consumption (approximately 17 mW). This high response may have resulted from a significant contribution of the resistance component near the electrode. Optical characterizations confirmed that the LaNiSbWO₄-G-PPy gas sensor showed similar optical properties to a typical display device. From gas-sensing results, the LaNiSbWO₄-G-PPy gas sensor exhibited high response to CO₂ in concentration range of 200–4000 ppm at room temperature and high selectivity against CO₂. Furthermore, the LaNiSbWO₄-G-PPy gas sensors offer good repeatability, reproducibility, and measurement accuracy. A sensing mechanism of LaNiSbWO₄-G-PPy gas sensor was explained based on the resistance change of graphene sensing layer via a direct charge transfer process. These results could pave the way to develop a new type of gas sensor.

Keywords:

• CO₂ sensor
• micromachined hotplate
• LaNiSbWO₄-G-PPy