Room-temperature hydrogen sensing performance of Nb 2 O 5 nanorod arrays.

Nb 2 O 5 nanorod arrays with a hexagonal phase were in situ grown on Nb foil via a facile hydrothermal method. The aspect ratio and spacing of the Nb 2 O 5 nanorods increased upon an increase in the reaction temperature. A pair of platinum electrodes was deposited on the surface of the Nb 2 O 5 nanorod arrays to form a hydrogen sensor. The sensor based on Nb 2 O 5 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 2 at room temperature. The Nb 2 O 5 nanorod arrays also showed good selectivity of H 2 against C 2 H 6 O, CO and NH 3 . The hydrogen sensing performance can be attributed to the reaction between chemisorbed oxygen species and H 2 . The Nb 2 O 5 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.