Ultrasensitive Detection and In-Depth Chemical Mechanism Study Toward Ethanol Vapor for LaCoO3/SnO2 Nanoflower

LaCoO 3 nanoparticles were synthesized using sol-gel method, and LaCoO 3 / SnO 2 nanoflower-like materials were successfully prepared by hydrothermal method. Various characterization techniques were employed to analyze their microstructures and elemental compositions. LaCoO 3 /SnO 2 exhibited significant improvements in gas response, response time, and selectivity compared to SnO 2 sensors. At the optimal operating temperature of 260°C, LaCoO 3 /SnO 2 demonstrated a maximum response of 219 to 100 ppm ethanol vapor, which was 8.4 times higher than that of pure SnO 2 . Additionally, the response time of LaCoO 3 /SnO 2 was reduced to 17s and showed good selectivity. The improved gas-sensitive performance of LaCoO 3 /SnO 2 was probably due to the heterojunction generated by the introduction of LaCoO 3 and the increase of specific surface area. The density of states, adsorption energy and charge density of adsorbed ethanol gas before and after the modification of SnO 2 by LaCoO 3 were analyzed using the first-principles to further explain the enhancement mechanism of LaCoO 3 /SnO 2 heterojunctions.