SnO2 recycled from tin slime for enhanced SO2 sensing properties by NiO surface decoration

Tin slime is a byproduct of the electroplating tin production line. Tin slime is an important secondary resource, the main component of which is SnO2. In this paper, we discussed an environmentally friendly method to recover SnO2 from tin slime. The recovered SnO2 decorated by NiO has an excellent sensing response to SO2. The morphology, structure and surface state of the prepared materials were characterized by X-ray diffraction (XRD), N-2 adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray phoyoelectron spectroscopy (XPS), and Raman spectroscopy. The SnO2 dispersed by PEG-400 exhibits smaller and more dispersed nanoparticles, which show responses of 6.5-100 ppm SO2 at 300 degrees C. Compared to the SnO2 sensor, the NiO surface decorated SnO2 sensor has significantly enhanced SO2 sensing performance, with a higher gas response, lower operating temperature and better selectivity. The sensing response of the NiO surface decorated SnO2 material to 100 ppm SO2 at 240 degrees C is as high as 10.38. This result likely occurs due to the increased oxygen vacancies and the formation of the p-n heterojunction between n-type SnO2 and p-type NiO. Importantly, this research has developed a simple and efficient method to recover SnO2 from the secondary resource tin.