Improved gas-sensitive properties for ethanol and acetone in Zn-doped CoTiO₃ nanoparticles

Appropriate element doping is an important means to improve gas response. Pure and Zn-doped CoTiO₃ nanoparticles were fabricated by a simple sol–gel method and their gas response to ethanol and acetone was studied. Compared with pure CoTiO₃ nanoparticles, particle dispersion, specific surface area, oxygen vacancy defects, and gas-sensitive properties of Zn-doped CoTiO₃ nanoparticles are optimized and improved. With the increase of Zn doping concentration, the aggregates composed of irregular nanoparticles disperse loosely and the oxygen vacancy defects on the CoTiO₃ nanoparticles’ surface accordingly increase. The optimum operating temperature of Zn-doped CoTiO₃ nanoparticles is slightly reduced from 286 to 260 °C. CoTiO₃ nanoparticles with Zn doping concentration of 0.05 especially show excellent gas-sensing properties. The sensitivities of Co_0.95Zn_0.05TiO₃ nanoparticles to 50 ppm ethanol and acetone are as high as 125.8 and 143.4, increased to 1.98 and 1.74 times higher than those of pure CoTiO₃ nanoparticles. The linear fitting of logarithmic relationship between sensitivity and concentration shows that Zn-doped CoTiO₃ can accurately detect low concentration (< 100 ppm) of ethanol and acetone. The improvement of gas response of Zn-doped CoTiO₃ nanoparticles is proposed to attribute to the synergistic effect of the agglomeration state of irregular particles and abundant oxygen vacancies on the surface due to Zn doping.