Synthesis of perovskite nanotubes via galvanic replacement reaction for gas sensing

Abstract

Designing gas sensors with a lower detection limit is necessary to exhaled breath analysis for early diagnosis, which is a critical issue in health status. In addition, acetylene gas can be used as a specific marker for smoking status and air pollution. Here, a synthesis of SnO$_2$/LaFeO$_3$ nanotubes (NTs) is suggested through an electrospinning technique with galvanic replacement reaction (GRR), which dramatically improves acetylene sensing behavior. The controlled GRR process provides SnO$_2$/LaFeO$_3$ NTs with a high surface area (146.6 m$^2$g$^{-1}$) by generation of SnO$_2$ nanograins (< 10 nm) and catalytic p-n heterojunctions by controlled reaction time with Sn precursor solution. Owing to the advantage of these features, the GRR treated SnO$_2$/LaFeO$_3$ NTs exhibited 31.2-fold higher acetylene response with fast response speed (16 s) compared to pristine LaFeO$_3$ NTs (64 s). These results demonstrate that GRR can be used to enhance the gas sensing performance with controllable morphology and compositions of 1D metal oxides.