The role of oxygen vacancies in the sensing properties of Ni substituted SnO2 microspheres

The influence of Ni doping in SnO2 microspheres was investigated in this study. SnO2 was doped with different amounts of Ni using a simple dipping method. The doped SnO2 structure, which was confirmed from X-ray photoelectron (XPS) and photoluminescence (PL) spectroscopies, was shown to possess distinctly more oxygen vacancies. Oxygen vacancies were found to be responsible for the surface adsorption of oxygen, as shown in the O 1s XPS spectrum and O2-TPD (temperature programmed desorption) measurements which can enhance the sensitivity of materials. According to the gas sensing properties, Ni-doped SnO2 was enhanced towards ethanol and showed excellent stability at the operating temperature. At 1 ppm of ethanol vapor, the response value of Ni substituted SnO2 was about 3 times that of pristine SnO2 microspheres. This research reveals a notable perspective for the design of sensing materials in terms of Ni substitutional doping.