Gas sensor based on three dimensional Bi2S3 nanowires network for ammonia detection at room temperature.

A film containing three dimensional Bi 2 S 3 nanowires network was obtained using Bi(NO 3 ) 3 and thioacetamide as starting materials through three steps, namely the chemical synthesis of Bi 2 S 3 , preparation of its sol under ultrasonic condition and crystal self-assembly at 25 °C. The nanowires had diameters of 20–100 nm. The formation mechanism of the 3D nanowires network is the anisotropic growth of Bi 2 S 3 . The sensor based on 3D Bi 2 S 3 nanowires network with an excellent response to ammonia at 30 °C. The response mechanism of the sensor for ammonia is a weak coordination adsorption of ammonia molecule on the Bi 2 S 3 nanowires and the electron is partially transferred from ammonia molecule to bismuth (III) ion. The maximum response of the sensor to ammonia was up to 82.3 and had a good linear range from 30 to 350 ppm concentration, indicating its potential applications in the determination and leak alarm of ammonia. [ABSTRACT FROM AUTHOR]