Ultrasensitive ethanol sensor based on Ce-modified SnO2 nanoflowers at low temperature

The improvement of ethanol gas-sensitive properties of SnO2 gas sensors is significant for the practical applications. The structures of pure SnO2 and Ce-modified SnO2 nanoflowers with different Ce contents (1 at%, 3 at% and 5 at%) were successfully prepared by a facile and environment friendly hydrothermal method with catalysis by CTAB and calcination in the air. The crystalline phase, morphology and chemical composition of the obtained SnO2 nanomaterials were analyzed, indicating that all four materials are flower-like structures assembled by nanosheets. The gas sensing behaviors of the fabricated sensors were systematically investigated. The results showed that Ce doping can significantly improve the sensing performance of the SnO2 gas sensors. The sensor based on 5 at% Ce-SnO2 nanoflowers exhibited not only high response (55), quick response/recovery time (7 s/9 s), excellent selectivity, but also long-time stability for 200 ppm ethanol at a lower operating temperature (125 °C). Furthermore, the gas sensing mechanism was also discussed in detail.