Tourmaline@ZnO nanoplates for n-butanol detection induced by the polarized electric field and its DFT study of ZnO (001) surface

N-butanol is a main kind of volatile organic compounds (VOCs) that cause increasingly serious environmental and health issues. Many efforts have been taken to curb the damage as a crucial task is to efficiently detect the VOCs. Although plenty kinds of gas sensors have been fabricated, there remains scarce research covering high response-value for n-butanol. Therefore, ZnO nanoplates exposing preferentially (001) surface have been synthesized around cores of tourmaline particles, which provide an electric field by spontaneous polarization and enhance gas-sensing sensitivity targeting n-butanol. XRD, SEM, TEM, XPS, BET, and UV–vis measurements were carried out to measure morphology, microstructure, as well as surface and electron states. We varied the mass ratio of tourmaline to ZnO and found 5wt%Toumaline@ZnO nanoplates achieved the most excellent response value which is approximately four times higher than the pristine ZnO, along with the fine repeatability for 100 ppm n-butanol and favorable recovery for different concentration of n-butanol at 340 °C. To explain the excellent gas sensing performance, the density functional theory calculations were conducted. It was been found that the ZnO (001) surface tends to polarize by the electric field of tourmaline. Furthermore, the electric field strengthens the electron accumulation on the ZnO (001) surface and provides more density of states near the Fermi level for superior gas sensitivity, thus effectively enhancing the performance and stability of the Toumaline@ZnO composited system.