Hollow ZnO@SnO₂–Pt Core–Shell Nanofibers for Ethanol Sensing

In this study, ZnO@SnO2–Pt core–shell nanofibers with a hollow structure have been prepared by coaxial electrospinning and heat treatment. The core–shell and hollow structures of nanofibers were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Brunauer–Emmett–Teller (BET) specific surface area test shows that the specific surface area of ZnO@SnO2–Pt core–shell nanofibers is larger than those of ZnO@SnO2 core–shell nanofibers and SnO2 nanofibers. The gas-sensing test result shows that the response to 100 ppm ethanol gas is 132.04 and the response time is 5 s at 200 °C for ZnO@SnO2–Pt core–shell nanofibers with 0.3 wt % Pt. Compared with those of ZnO@SnO2 core–shell nanofibers without Pt and pure SnO2 nanofibers, the optimum working temperature of ZnO@SnO2–Pt core–shell nanofibers is reduced by 125 °C and the maximum response is increased by 70.9 and 367.7%. Furthermore, the gas-sensing mechanism is discussed in detail.