A two-step synthesis of microsphere-decorated fibers based on NiO/ZnSnO3 composites towards superior ethanol sensitivity performance

Abstract

A novel systematic heterostructures based on NiO/ZnSnO3 microsphere-decorated fibers were produced with a simple two-step process based on the electrospinning and hydrothermal procedures. A large density of NiO microspheres were homogeneously and epitaxially decorated on ZnSnO3 nanofibers. The crystal, structural and surface compositional properties of sample based on NiO/ZnSnO3 composites were investigated by XRD, SEM, TEM, EDX, XPS and BET characterization. The complex heterostructure based on NiO/ZnSnO3 microsphere-decorated fibers had shown an extremely huge specific surface area with mesoporous nature, which is essential for superior gas sensors. The as-produced sensors based on NiO/ZnSnO3 composites display superficially improved sensing characteristics, including high sensitivity and selectivity response with fast response and recovery speed towards ethanol gas at low operational temperature as compare to pure ZnSnO3 nanofibers. The sensitivity response of sensor based on NiO/ZnSnO3 microsphere-decorated fibers were 23.95 towards 20 ppm ethanol gas at 160 °C, which was about 2.5 times superior than that of bare ZnSnO3 nanofibers. The upgraded sensitivity performance of composites based on NiO/ZnSnO3 microsphere-decorated fibers might be ascribed to the large specific surface area with mesoporous nature having enormous quantity of oxygen contents, p-n heterojunction effects and synergetic actions between NiO and ZnSnO3 heterostructure.