Ultrafine Pt NPs-Decorated SnO₂/α-Fe₂O₃ Hollow Nanospheres with Highly Enhanced Sensing Performances for Styrene

Styrene, a chronic toxic gas, is of great harm to human health. It is urgently required to develop a portable, efficient, and inexpensive method to detect this toxic gas. Chemiresistive gas sensor based on semiconductor metal-oxides is considered as one of the best candidate suited to above features, while its sensitivity and selectivity are not enough high for the applications. Herein, the ultrafine Pt NPs embellished SnO₂/α-Fe₂O₃ hollow nanoheterojunctions were achieved by in-situ reduction and subsequent calcination treatment. Particularly, such yielding products exhibited excellent styrene sensing performances with a detection limit of 50 ppb and extremely fast response/recovery time (3/15 s, respectively). More importantly, this SnO₂/α-Fe₂O₃/Pt sensing platform revealed improved styrene selectivity against other malodorous gases. Additionally, the significant enhancement for styrene sensing response was also obtained compared to other two sensors (pristine SnO₂ and SnO₂/α-Fe₂O₃, respectively). Further studies demonstrated that such enhanced performances possibly be owing to the "catalytic sensitization" effect driven by Pt NPs and "electronic sensitization" effect triggered through the formation of Schottky junction as well as n-n nanoheterojunction. Based on these sensing features, it is probably great promising in the detection of styrene gas in the future.