Room temperature hydrogen sensing properties of multiple-networked Nb2O5-nanorod sensors decorated with Pd nanoparticles

Nb2O5 nanosensors showing good sensing performances toward hydrogen and oxygen at high temperatures have been reported several times, but high-performance room-temperature Nb2O5 gas sensors have not been reported to date. Pd-Nb2O5 nanorods were synthesized by using thermal oxidation of a Nb foil, followed by wet chemical coating of Pd under UV illumination. The responses of multiple-networked Pd-Nb2O5 nanorod sensors to 10,000 ppm of hydrogen at room temperature were 218% and 496%, respectively. Responses obtained in this study were far higher than that to 2,000 ppm of H-2 obtained previously at the same temperature by using Pt/Nb2O5 Schottky-diode sensors. These results suggest that multiple-networked 1D nanostructure sensors, which can be fabricated more easily, are superior in H-2-gas-sensing properties to Schottky-diode-type nanostructure sensors, which require precise techniques to connect the nanostructures. The origin of the enhanced sensing properties of the Pd-decorated Nb2O5 nanorods toward hydrogen is also discussed.