Al and W co-doped NiO nanoflowers with low crystallinity and rich oxygen vacancies for high stability and selective triethylamine detection

In this work, pure NiO, Al-doped NiO, W-doped NiO and a series of Al/W co-doped NiO nanoflowers were successfully prepared through a simple solvothermal method . Various characterization methods, such as XRD , SEM, TEM, HRTEM and XPS , were used to confirm the physical and chemical properties of the sensitive materials in terms of micro-nano structures, compositions and elemental distributions. The as-obtained Al/W co-doped NiO showed a nanoflower structure with an approximate size of ∼ 200 nm. What's more, among six sensors constructed from the sensitive materials, the sensor based on 3 at% Al 3+ /3 at% W 6+ co-doped NiO (3Al3W-NiO) achieved the highest response (R g /R a =112) toward 100 ppm triethylamine with a low detection limit (1 ppm) at 325 ℃. Besides, this sensor also exhibited excellent response/recovery characteristics and long-term stability. These favorable sensing performances of the 3Al/3 W co-doped NiO sensor are not only modulated by the initial resistance (R a ), but are also closely related to the large specific surface area , porous structures , low crystallinity , rich oxygen vacancies and high Ni 3+ /Ni 2+ ratio in the composite nanomaterials.