Formaldehyde gas response and selectivity of ZnO-SnO2 gas sensors

This study aimed to develop a gas sensor based on a ZnO-SnO 2 nanocomposite fabricated via ultrasonic chemical synthesis and to evaluate its ability to detect formaldehyde gas. The response, recovery, and selectivity of a series of sensors employing ZnO-SnO 2 nanocomposite samples produced using various synthesis energy levels were systematically evaluated. The experimental results revealed that the sensor using the ZnO-SnO 2 nanocomposite fabricated with a synthesis energy of 100,000 J produced the strongest response to formaldehyde gas and the fastest recovery time. It also demonstrated excellent selectivity when compared to toluene gas. These findings suggest that the use of an optimal synthesis energy can enhance the surface characteristics of ZnO-SnO 2 nanocomposites, thus improving their sensing performance. • The ZnO-SnO 2 gas sensor was fabricated using ultrasonic chemical synthesis, achieving optimized performance for HCHO gas. • The 100,000J sensor showed 92 %, 56 %, 20 % sensing performance at 20 ppm, 1 ppm, 0.1 ppm range. • This study aimed to improve the selectivity for formaldehyde, and excellent sensing performance was confirmed. • The sensor showed excellent selectivity for HCHO gas over toluene gas, indicating its potential for selective VOC detection.