A novel coral-shaped Dy2O3 gas sensor for high sensitivity NH3 detection at room temperature

The coral-shaped Dy 2 O 3 was prepared by a simple and environmentally friendly hydrothermal reaction combined with subsequent calcination. The coral-shaped Dy 2 O 3 was assembled by clusters, which were constructed by nanoparticles, whose sizes are 12.3   ±   3.6   nm. The gas sensors were investigated with nine gases at room temperature, and show a high response and selectivity to NH 3 . Compared with other reported metal oxide-based sensors, Dy 2 O 3 sensor exhibits not only high sensitivity, good selectivity and reproducibility to NH 3 at room temperature, but also two good linear relationships when the concentration of NH 3 is in the range of 0.1–1   ppm and 1–100   ppm. The good gas sensing property is mainly because of the 3D hierarchical structure of coral-like Dy 2 O 3 , which has a large specific surface area. This benefits NH 3 molecules to adsorb/desorb onto/from the surface as well as the electron transfer. In addition, the possible NH 3 -sensing mechanism is discussed in detail.