Surface Segregation and Consequent SO₂ Sensor Response in SnO₂−NiO

Many studies have been carried out concerning the development of SO 2 sensors to detect and avoid its health prejudicial effects. However, there is still a lack of reliable, high-speed-response sensors that work at room temperature. In this work, the segregation of Ni in the SnO 2 −NiO system is used to obtain a rapid SO 2 sensor response. Segregation and its structure consequences were studied by electron dispersive spectroscopy, infrared spectroscopy, and high-resolution transmission electron microscopy in nanopowders of SnO 2 −NiO with different compositions prepared by a polymeric precursor method. The sensor activity of SnO 2 −1 mol % Ni was studied and a linear calibration curve was formed with a maximum limit response of 32 ppm SO 2 .