Preparation and characterization of ZnO/CoNiO2 hollow nanofibers by electrospinning method with enhanced gas sensing properties

ZnO nanofibers, ZnO/CoNiO2 nanofibers, and ZnO/CoNiO2 hollow nanofibers have been successfully synthesized by an electrospinning method and post calcination treatment. Polyvinylpyrrolidone (PVP) solution and polystyrene (PS) solution were chosen as a facility to form core-sheath nanofibers after spinning of two precursor solutions together. The structure and composition of ZnO nanofibers (nfs), ZnO/CoNiO2 nanofibers (nfs) and ZnO/CoNiO2 nanotubes (nts) are confirmed by X-ray diffraction (XRD), energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS). High response (240), rapid response (8 s) and recovery (11 s) behaviors with regard to ammonia gas have been successfully achieved from ZnO/CoNiO2 hollow nanofibers to 100 ppm concentration test gas at an optimal temperature of 220 °C. Response (40) at low temperature (80 °C) has clearly observed. Large specific surface areas were achieved by increase of porosity and shrinkage in diameter of ZnO/CoNiO2 hollow nanofibers.