Room-temperature detection of acetone gas by PANI/NiO-loaded TiO2 nanoparticles under UV irradiation

Ultraviolet (UV) irradiation enhances the photocatalytic properties of metal oxide semiconductors, including titanium dioxide (TiO2). Accordingly, the power consumption of room temperature metal oxide gas sensors might be greatly reduced by irradiation with UV light. In the present study, the p-type materials nickel oxide (NiO) and polyaniline (PANI) are loaded into TiO2 nanoparticles (NPs) by the sol-gel method, and the acetone-sensing properties are investigated at various operating temperatures in the presence and absence of UV illumination. The PANI/NiO co-loaded TiO2-NP composite gas sensor exhibits the highest performance under UV illumination at room temperature (25 degrees C). In particular, with the excellent stability even after six months, 0.01 wt% PANI-loaded 0.9-TiO2-0.1-NiO NPs showed a selective response of 11.3-50 ppm acetone gas at 25 degrees C, along with a limit of detection of 176.2 ppb. The detailed mechanisms for improved gas sensing are explained in terms of the fundamental properties of materials. In brief, the realization of a low power-consumption acetone gas sensor can be successfully realized by using a combination of NiO, PANI, and TiO2 NPs, and that this approach can be extended to other similar systems.