Wireless Gas Sensor Based on the Mesoporous ZnO–SnO₂ Heterostructure Enables Ultrasensitive and Rapid Detection of 3-Methylbutyraldehyde

Abstract

Achieving ultrasensitive and rapid detection of 3methylbutyraldehyde is crucial for monitoring chemical intermediate leakage in pharmaceutical and chemical industries as well as diagnosing ventilator-associated pneumonia by monitoring exhaled gas. However, developing a sensitive and rapid method for detecting 3-methylbutyraldehyde poses challenges. Herein, a wireless chemiresistive gas sensor based on a mesoporous ZnO− SnO 2 heterostructure is fabricated to enable the ultrasensitive and rapid detection of 3-methylbutyraldehyde for the first time. The mesoporous ZnO−SnO 2 heterostructure exhibits a uniform spherical shape (∼79 nm in diameter), a high specific surface area (54.8 m 2 g −1 ), a small crystal size (∼4 nm), and a large pore size (6.7 nm). The gas sensor demonstrates high response (18.98@ 20 ppm), short response/recovery times (13/13 s), and a low detection limit (0.48 ppm) toward 3-methylbutyraldehyde. Furthermore, a real-time monitoring system is developed utilizing microelectromechanical systems gas sensors. The modification of amorphous ZnO on the mesoporous SnO 2 pore wall can effectively increase the chemisorbed oxygen content and the thickness of the electron depletion layer at the gas−solid interface, which facilitates the interface redox reaction and enhances the sensing performance. This work presents an initial example of semiconductor metal oxide gas sensors for efficient detection of 3methylbutyraldehyde that holds great potential for ensuring safety during chemical production and disease diagnosis.