A pulse-driven sensor based on ordered mesoporous Ag2O/SnO2 with improved H2S-sensing performance

Ordered mesoporous Ag2O/SnO2 was synthesized via nanocasting method using hexagonal mesoporous SBA-15 as template. As-prepared Ag2O/SnO2 samples were characterized by X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy, energy-dispersive X-ray analysis, and X-ray photoelectron spectroscopy. A microspheric directly heated gas sensor based on the mesoporous Ag2O/SnO2 was fabricated, and its gas sensing performance was investigated. Results indicated that the sensor based on mesoporous Ag2O/SnO2 exhibited excellent selectivity, high response, and good stability to H2S at 100 °C. A pulse-driving method was then introduced to enhance the sensitivity to H2S. Under pulse-driving, the response of the sensor to 300 ppb H2S was 5.7, which was approximately two times higher than that under constant current, and the limit of detection was improved to 50 ppb. The high-sensing performance of the sensor was attributed to the composition and structure of mesoporous Ag2O/SnO2 and the pulse-driven mode.