Room-temperature hydrogen sensing performance of NbO nanorod arrays.

NbO nanorod arrays with a hexagonal phase were grown on Nb foil a facile hydrothermal method. The aspect ratio and spacing of the NbO nanorods increased upon an increase in the reaction temperature. A pair of platinum electrodes was deposited on the surface of the NbO nanorod arrays to form a hydrogen sensor. The sensor based on NbO nanorod arrays exhibited a fast and highly-sensitive hydrogen response with a sensitivity of 74.3% and a response time of 28 s toward 6000 ppm of H at room temperature. The NbO nanorod arrays also showed good selectivity of H against CHO, CO and NH. The hydrogen sensing performance can be attributed to the reaction between chemisorbed oxygen species and H. The NbO nanorods have a high aspect ratio, leading to an increase in the chemisorbed oxygen species on the surface of the [001] orientated nanorods. Moreover, arrays with a vertical structure have low quantities of junctions, which allow oxygen ions to diffuse more easily.