Fabrication of room temperature operated ultra high sensitive gas sensor based on mesoporous Ni doped WO$_3$ nanoparticles

Ultra high sensitive room temperature gas sensor based on Ni-doped WO$_{3}$ nanoparticles(hereafter NPs) has been reported here. The synthesis of pure and Ni-doped WO$_{3}$ NPs was done by facile precipitation route. XRD studies revealed the polycrystalline monoclinic structure of the prepared samples with the preferential growth orientation along (002) crystal plane. Analysis via SEM and FE-SEM was conducted, and the micrographs showed that the synthesized samples were found to have highly porous structure with excellent dispersibility. The successful incorporation of Ni$^{2+}$ ions in to WO$_{3}$ lattice has been confirmed by XPS analysis. The highly improved room temperature gas sensing characteristics of WO$_{3}$ by Ni doping is also studied using a high sensitive electrometer. Compared to undoped WO$_{3}$, 3 mol. % Ni-doped WO$_{3}$ sensor showed nearly 20-fold greater sensitivity (2641 – 200 ppm ammonia, room temperature) with rapid response/recovery times of 40/97 s.