Sensitive and Reversible Ammonia Gas Sensor Based on Single-Walled Carbon Nanotubes

Autor: Abniel Machín, María Cotto, José Duconge, Carmen Morant, Florian I. Petrescu, Francisco Márquez
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Chemosensors, Vol 11, Iss 4, p 247 (2023)
Druh dokumentu: article
ISSN: 2227-9040
DOI: 10.3390/chemosensors11040247
Popis: The present study reports on the fabrication and performance of ammonia sensors based on single-walled carbon nanotubes (SWCNTs) coated with gold nanoparticles (AuNPs). The AuNPs were incorporated onto the SWCNTs using two different methods: sputtering and chemical deposition. The sensors were exposed to controlled concentrations of ammonia at two temperatures, namely, 25 °C and 140 °C, and their response was monitored through successive cycles of ammonia exposure (0.5 ppm and 1.0 ppm) and nitrogen purging. The results demonstrate that the sputtering-based deposition of the AuNPs on SWCNTs led to the best sensor performance, characterized by a rapid increase in resistance values (tresp = 12 s) upon exposure to ammonia and an efficient recovery at 140 °C (trec = 52 s). By contrast, the sensor with chemically impregnated AuNPs exhibited a slower response time (tresp = 25 s) and the same recovery time (trec = 52 s). Additionally, a novel device was developed that combined MoS2-AuNPs (sputtering)-SWCNTs. This sensor was obtained by impregnating nanosheets of MoS2 onto AuNPs (sputtering)-SWCNTs showing improved sensor performance compared to the devices with only AuNPs. In this case, the sensor exhibited a better behavior with a faster recovery of resistance values, even at room temperature. Overall, the study provides valuable insights into the fabrication and optimization of SWCNT-based ammonia sensors for various applications, particularly in detecting and quantifying small amounts of ammonia (concentrations below 1 ppm).
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