Room-temperature hydrogen gas sensing properties of the networked Cr₂O₃-functionalized Nb₂O₅ nanostructured sensor

Abstract

Cr₂O₃-functionalized Nb₂O₅ nanoparticles were synthesized via a facile hydrothermal route. The multiple-networked Cr₂O₃-functionalized Nb₂O₅ nanostructured sensor showed enhanced H₂ gas sensing performance compared to its pristine Nb₂O₅ nanostructure counterpart. The Cr₂O₃-functionalized Nb₂O₅ nanostructure sensor showed responses of 5.24 to 2 ppm of H₂ at room temperature, whereas the pristine Nb₂O₅ nanoparticle sensors showed responses of 2.29. The former also exhibited a faster response to H₂. The multiple-networked pristine and Cr₂O₃-functionalized Nb₂O₅ nanostructured sensors were stronger and much shorter, respectively, than other nanomaterial-based Schottky diode-type sensors and Nb₂O₅-based Schottky diode-type sensors. The underlying mechanism for the enhanced sensing performance of the Cr₂O₃-functionalized Nb₂O₅ nanostructured sensor towards H₂ gas is discussed in detail. Particular emphasis is placed on the role of the Cr₂O₃-Nb₂O₅ p-n junction in the Cr₂O₃-functionalized Nb₂O₅ nanostructure sensor.