Room temperature gas sensors based on Ce doped TiO2 nanocrystals for highly sensitive NH3 detection

Abstract

Room-temperature gas sensors with high performance have shown unexpected potential in practical application. This work developed a series of Ce doped TiO2 nanocrystals via microwave-assisted solvothermal method for detecting ammonia (NH3) at room temperature. All the samples presented small-size nanocrystals and good crystallinity. The 0.43 at% Ce-TiO2 nanocrystals with a large specific surface area of 266.9 m2·g−1 exhibited the distinguished NH3 sensing performance at room temperature, including high response (23.99 @ 20 ppm), low limit of detection (140 ppb), superior selectivity, repeatability, and operating stability. The enhanced sensing mechanisms were explained by the synergetic strategy of re-orientated high energy facets, oxygen vacancy and large specific surface area, which boost the surface activity and charge transfer efficiency. The enhanced sensing mechanism was further verified through DFT calculations. Moreover, the practical application potential was also evaluated for the fish freshness detection. This work will provide a direction that rapidly synthesizing rare earth element doped metal oxides for high-performance room temperature gas sensors.