Structure and electrical properties of electrospun ZnO–NiO mixed oxide nanofibers

ZnO–NiO mixed oxide nanofibers have been successfully produced from a solution containing poly 4-vinyl phenol and Zn and Ni acetic acids by an electrospinning method. The calcination process of the ZnO–NiO/PVP composite nanofibers brings forth polycrystalline two-phase ZnO–NiO nanofibers of 30–50 nm in diameters. ZnO and NiO crystallize into würtzite and rock salt structures, respectively. The electrical conductivity of ZnO–NiO nanofibers increases with an increase in temperature, which has been attributed to the thermal emission of carrier from the energy state of the grain boundaries. The activation was estimated to be 0.5 eV. The capacitance of ZnO–NiO nanofibers upon NOx gas exposure was observed to decrease. The feasibility of producing ZnO–NiO mixed oxide nanofibers opens a new door for capacitive gas sensors.