| 초록 |
Benzene is a highly toxic and ubiquitous gas known to induce leukemia. Accordingly, the precise monitoring of sub-ppm-level benzene is indispensible to evaluate both indoor and outdoor air quality and to protect human being from toxic gas. Unfortunately, the BTX gases with benzene ring are chemically stable and thus less reactive to oxide semiconductor gas sensors. Moreover, similar chemical structures of BTX gases hamper the discrimination among BTX gases. In this study, a new strategy to detect sub-ppm-level benzene vapor in a highly selective manner using oxide semiconductor chemiresistors has been suggested. The Pd-loaded SnO2 yolk-shell sensing film coated with thin catalytic Co3O4 overlayer showed ultrahigh response (resistance ratio = 89) to 5 ppm benzene with negligibly low cross responses to other representative and ubiquitous indoor pollutants such as toluene, xylene, HCHO, CO, and ethanol. Such a high performance of benzene detection is explained in that the synergistic combination of catalytic Co3O4 layer and Pd-loaded SnO2 yolk-shell micro reactors promoted the reforming of extremely stable benzene into smaller and more active species, while it oxidized other representative indoor pollutants such as toluene, xylene, HCHO, and ethanol into non- or less-reactive species. |
