P2.4.9 Synthesis of Au/SnO2 core-shell NPs with thick shell and their CO sensing properties in low temperatures

Au/SnO2 core-shell structure nanoparticles (NPs) with different shell thicknesses as a CO gas sensing material were synthesized by microwave-assistant hydrothermal method. The thickness of SnO2 shell was controlled from 7 nm to 22 nm. The concentrated Au/SiO2 NPs colloid was loaded on alumina circuit board with interdigitated Pt electrodes for gas sensing test, and then heat-treated 500°C in electric furnace for 24 h. The sensor device showed the highest response for CO gas when the thickness of SnO2 shell was 18 nm and the test temperature was 200°C. This sensor device showed high response even at 100°C of test temperature.