Polyoxometalates electron acceptor-intercalated In2O3@SnO2 nanofibers for chemiresistive ethanol gas sensors

Polyoxometalates (POMs), as a kind of electron acceptors, comes into sight in gas sensing field. Here, we in situ construct a group of polyoxomethoate/semiconductor one-dimensional tandem heterojunction materials using convenient one-step coaxial electrospinning method. A polyoxometalates electron acceptor layer was intercalated into In2O3@SnO2 nanofibers (NFs), forming In2O3@PW12@SnO2 coaxial core-middle-shell NFs. Gas sensing performances of the one-dimensional In2O3@PW12@SnO2 tandem heterojunctions were investigated for the first time. The fabricated NFs exhibited excellent detection performances for ethanol gas. The optimal sensitivity response to 100 ppm ethanol can reach 22.6, which is about 4 times that of POMs-free samples. Other gas sensing parameters were also comprehensively studied. The significant enhancement can be attributed to the addition of appropriate amount of PW12 electron acceptor which accelerate electrons transfer and reduce the recombination of electron-hole pairs. This work provides a novel strategy for developing high performance gas sensors by constructing tandem heterojunctions as well as introducing POMs electron acceptor, and offers new insight into the development of POMs-based gas sensors.