Hydrogen sensing properties of multiple networked Nb2O5/ZnO core-shell nanorod sensors

Nb2O5 nanosensors with good sensing properties toward hydrogen and oxygen gases at high temperatures have been reported, but sensing performances of Nb2O5-based gas sensors are still unsatisfactory. This study examined the sensing properties of Nb2O5-core/ZnO-shell nanorod sensors toward H-2 gas. The responses of pristine Nb2O5 and Nb2O5-core/ZnO-shell nanorods to 10,000 ppm H-2 at 300 degrees C were similar to 250% and similar to 586%, respectively. The response and recovery times of Nb2O5-core/ZnO-shell nanorods at 10,000 ppm H-2 at 300 degrees C were 17 and 23s, respectively, whereas those of pristine Nb2O5 nanorods were 23 and 32s. The response of the core-shell nanowire sensor to H-2 gas showed strong dependence on the shell layer thickness. The strongest response was obtained with a ZnO shell layer thickness of 46nm, which is equal to the maximum depletion layer width in the shell. The origin of the enhanced sensing properties of Nb2O5-core/ZnO-shell nanorods toward H-2 is also discussed. (C) 2014 Elsevier B.V. All rights reserved.