A high throughput platform screening of ppb-level sensitive materials for hazardous gases

Hazardous gases such as formaldehyde, benzene, toluene and xylene are harmful to human health. Utilizing sensors with extraordinary gas sensing performances to detect these gases is essential to air quality monitoring. According to indoor air quality standard of China (IAQS, GB/T 18883-2002), the detection limits for formaldehyde, benzene, toluene and xylene are 0.075 ppm, 0.034 ppm, 0.047 ppm, 0.042 ppm respectively. While the detection limits of current commercial metal oxide (MOX) gas sensors to these four gases are approximately 1 ppm or more, which does not meet the IAQS. In this research, a high-throughput screening platform for screening MOX gas sensing materials with high gas sensing performances was designed and established. Thirty-one metal ions modified sensing films based on SnO2 and an intrinsic SnO2 sensing film were parallel deposited. Their sensing performances were characterized with this platform. Ir-modified SnO2 and Ag-modified SnO2 with high sensing performances were selected out. The detection limits of these four gases were 20 ppb by temperature programmed cooling method. This platform and study contribute to improve the efficiency of material screening and realize the detection of low concentration hazardous gases.