Oxygen Vacancies Induced Performance Enhancement of Sensitivity to Acetone Using La-Doped ZnSnO3 Nanosheets: Experimental and DFT-D3 Study

To develop a sensor for acetone gas at low concentrations to protect the environment and human health, La-doped ZnSnO3 (LZSO, La:Sn = 0.25 at%, 0.5 at%, and 1 at%) nanosheets were prepared by a hydrothermal method. The gas-sensing capabilities were extensively examined. According to the results, the optimal doping amount is La: Sn = 0.25 at% (LZSO1), and the LZSO nanosheets demonstrated the best responses of 16.83 and 427.44 at 5 and 100 ppm acetone, respectively, at the optimal working temperature (325 °C). The gas-sensing performance was greatly enhanced compared to that of the ZnSnO3 nanosheets. The concentration of oxygen vacancies (VO) was improved by La doping, which is advantageous for acetone gas-sensing performance. Furthermore, the findings of theoretical calculations suggested that La doping can increase the formation of surface oxygen vacancies, which was consistent with the results of the experiments. The VO can activate the surface, reduce the work function, and promote oxygen adsorption, which is beneficial for electron transfer. Thus, the method of doping La $^{{3}+}$ into ZnSnO3 nanosheets is promising for developing high-performance acetone gas sensors.