Enhanced gas-sensing performance of ZnO@In2O3 core@shell nanofibers prepared by coaxial electrospinning

Abstract

One-dimensional ZnO@In2O3 core@shell nanofibers (CSNFs) were synthesized via a facile coaxial electrospinning method followed by high-temperature pyrolysis treatment. The obtained nanofibers have a well-defined core@shell structure with ZnO as the core and In2O3 as the shell. Compared with the pure ZnO nanofibers and pure In2O3 nanofibers, the ZnO@In2O3 CSNFs based sensor presents the highest response to ethanol (31.87 at 100ppm) at an operating temperature of 225°C, which can be ascribed to the formation of a completely electron depletion layer in In2O3 shell. Moreover, the ZnO@In2O3 CSNFs based sensor also demonstrates outstanding selectivity, excellent stability and low detection limitation (∼5ppm) to ethanol vapor. The ultraviolet photoelectron spectroscopy confirms a type-II heterojunction formed at the interface of ZnO core and In2O3 shell. The main mechanism for the enhanced performance of ZnO@In2O3 CSNFs gas sensor is the depletion modulating of In2O3 shell layer in electron transfer. These results are valuable for the practical application of ZnO@In2O3 CSNFs in ethanol detection.