Two birds with one Stone: Fabrication of Bi2S3/f-MWCNTs nanocomposites for dual-functional gas sensor towards NH3 and acetic acid detection and discrimination at room temperature

Environmental safety monitoring has significantly benefited from the incorporation of gas sensors. Given the pernicious effects of ammonia and acetic acid gases on the environment and human health, it is imperative to develop a room temperature dual-functional gas sensor capable of simultaneously detecting both these gases. In this research endeavor, acid-functionalized multi-walled carbon nanotubes (f-MWCNTs) were integrated with Bi 2 S 3 through a hydrothermal approach, leading to the fabrication of a Bi 2 S 3 /f-MWCNTs-2 nanocomposite-based chemoresistive gas sensor. The results demonstrate that the Bi 2 S 3 /f-MWCNTs-2 sensor exhibits a response value of 52.7 % towards 100 ppm NH 3 at room temperature (25℃), displaying a declining resistance curve upon exposure to the target gas. Similarly, for 100 ppm CH 3 COOH under ambient conditions (25℃), the sensor records a response value of 72.55 %, accompanied by a rising resistance curve when in contact with CH 3 COOH gas. The distinctive feature of this dual-functional sensor lies in its ability to detect opposing transient response curves for the two gases, which is crucial for distinguishing between different gases. Furthermore, the sensor boasts swift response recovery, excellent repeatability, and robust stability. This study underscores the promising potential of the Bi 2 S 3 /f-MWCNTs-2 nanocomposite sensor in applications such as environmental monitoring.