A new strategy to one-step construct polyoxometalate/semiconductor one-dimensional tandem heterojunctions toward optimized conductometric sensing performances of ethanol gas

Gas sensing performances of homogenous semiconductors materials are limited by their high carriers recombination rate. Polyoxometalates (POMs), as a kind of electron acceptors, comes into sight in gas sensing field. In this study, three series of SnO2 @POMs@WO3 layered core-middle-shell nanofibers with tandem heterojunctions are first prepared utilizing one-step coaxial electrospinning. The tandem heterojunctions are continuously distributed in a one-dimensional line along the nanofibers. For the first time the gas sensing performances of onedimensional tandem heterojunctions are investigated. Furthermore, the effects of different contents and types of POMs on gas sensing performance are studied. The response of POMs-modified nanofibers can be significantly improved compared to SnO2 @WO3 nanofibers. The optimized response to 100 ppm ethanol can reach 8.8. The enhancement can be attributed to that the addition of POMs electron acceptor, the construction of POMs/ semiconductor tandem heterojunctions and the one-dimensional nano-structure can together promote the separation of carriers, which could remarkably improve gas sensing performances. These results provide a new strategy for developing high-performance gas sensors by synthesizing one-dimensional tandem heterojunctions as well as introducing POMs.

Automated summary

In this study, one-dimensional tandem heterojunctions of SnO2 @POMs@WO3 nanofibers were prepared using coaxial electrospinning, and the gas sensing performance was significantly improved compared to SnO2 @WO3 nanofibers. The optimized response to 100 ppm ethanol reached 8.8, providing a new strategy for developing high-performance gas sensors through synthesizing one-dimensional tandem heterojunctions and introducing POMs.