Synergistic tailoring of adsorption and vacancy enrichment in lamellar stacked layers of α-MoO3 nanorods by Mg2+ for NO2 gas sensor

Extremely toxic nitrogen dioxide (NO2) was detected using lamellar layered α-MoO3. The stable orthorhombic phase of MoO3 (α-MoO3) with preferential growth along (02k0) and the nano-rectangular rods (NRs) like morphology were observed. The incorporation of Mg2+ in α-MoO3 influenced the morphology and the oxygen vacancies (VO), which were analyzed through Raman, photoluminescence, and X-ray photoelectron spectroscopy. The core level spectra provided direct evidence for VO enrichment in 3 %Mg-α-MoO3 via emergence of peak at 531.02 eV with an area of 45.15 %. NO2 response was analyzed at 150–200 °C with various NO2 concentrations. 3 %Mg-α-MoO3 NRs provided maximum response of 133.9 % for 50 ppm with low limit of detection (LOD) of 250 ppb with good response (193 s) and recovery (260 s) transient behaviors. The fabricated sensor shows high selectivity to NO2 among H2S, SO2, N2O, and NH3, also good repeatability suggesting potential suitability for NO2 detection. [Display omitted] •α-MoO3 has preferential growth along (02k0) plane confirming the well lamellar stacks via Mg doping.•Aliovalent Mg2+ stimuli the aspect ratio of the Lamellar stacked nanorods, resulting in stronger solid-gas interactions.•Mg doped α-MoO3 exhibits excellent Long-term selectivity for NO2, quick response and good stability.•The high selectivity about 133.9% and low detection limit (250 ppb) offers promising sensor applications.