Interface defect engineering induced drastic sensing performance enhancement of W18O49@PANI nanowires for ammonia detection at room temperature

Abstract

Room temperature gas sensor with high response and excellent stability has drawn much attention owing to its huge demand. Surface structure designs in a micro and macro scale provide lasting inspiration and a promising avenue for designing advanced functionalities using nanomaterials. Here, the W18O49@polyaniline (PANI) nanowires with rich and stable surface defects in its core-shell structure were constructed via facile hydrothermal process combined with plasma treatment. The results indicate that the surface oxygen vacancy defects induced by argon (Ar) or hydrogen (H) plasma can act as an electron acceptor to promote the PANI coating to generate more protons that react with the target Ammonia (NH3). Additionally, the coated PANI shell also can avoid the re-oxidate of the obtained oxygen vacancies, leading to a more stable and enhanced gas response of NH3 at room temperature. We found that the gas response of NH3 can be enhanced by increasing surface defect concentration, which can reach 50 and 25 at 100 ppm at room temperature with H and Ar plasma treat, respectively. Besides, a stable response-recovery performance in multiple cycles of 30 days and multiple cycles can achieve. Our results suggest that this interface designed W18O49@PANI is a potential ammonia gas sensor material.