Highly selective and sensitive detection of methyl mercaptan by heterostructural CdS/(Sr_0.6Bi_0.305)₂Bi₂O ₇ chemiresistor

Methyl mercaptan (MM) is one kind of volatile sulfur compound (VSC) with odor and properties (inflammable, highly toxic, and corrosive) similar to H2S; therefore, the highly sensitive and selective monitoring of ambient MM by chemiresistors is strongly essential, but it remains a challenge owing to its relatively weak reducibility/response in comparison with H2S. In this study, a novel chemiresistor composed of hexahedral particles SBO-loaded CdS nanoparticles has been prepared via a facile chemical precipitation method for the super-sensitive and highly-selective recognition of MM. The heterostructural CdS/SBO (0.05%) chemiresistor exhibited an extremely high response (114.7) to 100 ppm MM at a relatively low operating temperature (100 & DEG;C) and was about 36- and 9-fold higher than pure SBO and CdS chemiresistor, respectively. Various characterizations suggested that the sulfurization-desulfurization reaction, the abundant oxygen vacancies, and the generation of n-n heterojunctions at the interface promote the redox reaction of surface-active substances, thereby, boosting the outstanding MM response characteristics. In addition, the heterostructural chemiresistor possesses good selectivity, weak humidity interference, a lower limit of detection (LoD) of 82 ppb, and long-term stability (& SIM;6% decline of response after 120 days), which promises practical applications in air quality (odor) monitoring.