The development of hydrogen (H2) gas sensors with high sensitivity at room temperature remains a challenge. In this work, Nb2O5/NiNb2O6 heterojunction nanowires with efficient H2 gas-sensing performance were successfully synthesized via a hydrothermal and calcination method. Results from X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) experiments demonstrated that nickel was uniformly distributed within the Nb2O5 lattice in the form of Ni2+. Scanning electron microscopy (SEM) observations revealed that Ni doping led to significant optimization of the composite’s nanowire structure. The sensor based on Nb2O5/NiNb2O6 heterojunction nanowires exhibited a response value of up to 13.35–5000 ppm of H2 at room temperature, with rapid response/recovery times (6/36 s), and the calculated lower limit of detection (LOD) was as low as 0.65 ppm. The excellent gas-sensing properties can be attributed to the creation of NiNb2O6 by Ni doping, which sequentially induces the formation of an n–n heterojunction between Nb2O5 and NiNb2O6, enhancing the surface depletion effect and amplifying the resistive response signal. This study proposes a material design approach for developing low-power sensors suitable for monitoring high-risk hydrogen concentrations at room temperature, demonstrating significant potential in hydrogen storage and transportation safety as well as industrial leakage early warning systems.
Jia et al. (Mon,) studied this question.