Oxygen vacancies mediated α-MoO3 Nano-ribbons by Cu doping for highly sensitive, selective and rapid detection of hazardous NO2 for gas sensor application

The demand for less toxic, less expensive, and low operating temperature-based sensors to enhance detection of NO2 leaks is driven by the growing concern over the hazardous impacts in many sectors. The superiority of layered structures and its better carrier transport is more desirable in gas sensors. The α-MoO3 is a rapidly developing hotspot material in the field of gas sensing due to its distinctive layered structure, accessibility, and environmental friendliness. Herein, α-MoO3 nano-ribbons (NRs) with increased carrier transport through oxygen vacancies (Vo) was achieved by Cu-doping. Interestingly, Vo and carrier concentration (n) enhanced in Cu-doped α-MoO3 NRs. Due to synergistic enhancements in mobility (μH ∼ 1.85 cm−2V−1s−1), diffusion coefficient (Dn ∼ 7.05 m2s−1) and n ∼ 6.07 × 1019, the Cu-doped (4 at%) α-MoO3 NRs selectively displayed an ultra-high response of 715% for 10 ppm of NO2 at an operating temperature of 170 ℃. Further, it showed high response (161%) for 10 ppm at 110 ℃. The ensuing low limit of detection (LOD) (∼18 ppb), repeatability (4 cycles), high selectivity among H2S, SO2, & NH3, and stability over 100 days revealed excellent activity for NO2 detection. This work offers promising strategy for the fabrication of MoO3 NRs that are adaptable for NO2 sensing.