Dual-Functional Tungsten-Doped Nio for Highly Sensitive Triethylamine Sensor with Ppb Level Detection Limit

Abstract

In this study, non-stoichiometric W-doped NiO nanoflowers were synthesized using a straightforward hydrothermal method, significantly enhancing the sensing performance towards triethylamine through dual-functional tungsten doping. The optimal doping concentration not only increased the specific surface area of NiO from 25.54 to 189.19 m2g-1 but also reduced the formation energy of oxygen vacancies from 5.349 eV to 4.227 eV. The sensor containing 4 at% W-doped NiO demonstrated exceptional sensitivity to triethylamine, achieving a detection level as high as 229 for concentrations of 100 ppm at 237.5°C. This triethylamine sensor represents a 135-fold enhancement over sensors fabricated from undoped NiO, and offers a rapid response/recovery time of 8 and 30 seconds, respectively. Furthermore, at a lower triethylamine concentration of 50 ppb, the sensor exhibited a response value of 1.32, indicating a lower detection limit.

Keywords: Gas sensor, Triethylamine, Tungsten doping, NiO, Oxygen vacancies