High sensitive room temperature ammonia sensor based on dopant free m-WO3 nanoparticles: Effect of calcination temperature

Abstract

In this article, monoclinic tungsten tri-oxide (m-WO 3) nanoparticles (hereafter NPs) were prepared by facile precipitation method and they were successfully examined as gas sensing materials for monitoring gaseous ammonia at room temperature have been reported. The effect of calcination temperature on structural and morphological properties of the prepared samples were also investigated. Physicochemical properties of the samples were characterized by XRD, SEM, XPS, UV-Vis and PL analysis. XRD studies confirmed the monoclinic structure of the prepared NPs. Optical studies disclosed that the obtained samples were having wider optical band gaps ranging from 2.48 to 2.76 eV. Sensing signatures such as selectivity, transient response along with performance indicators like repeatability and stability have also been investigated. Invitingly, the sample calcined at 823 K exhibited highly improved sensing response of 142 towards 200 ppm of ammonia with rapid response/recovery time of 26 / 79 s.

Fabrication of room temperature operated ultra high sensitive gas sensor based on mesoporous Ni doped WO3 nanoparticles

“…Pure WO 3 NPs were prepared according to our previous work [7], as well as the detailed preparation process has been explained as follows. were dissolved separately in 100 ml of de-ionized water (DI) to obtain 1.2 and 2 mM respectively.…”

“…The systematic evaluation of sensing performance of the prepared NPs was done using a customized gas sensing setup as described in our previous work [7]. In order to construct a sensing material the synthesized NPs were mixed with certain amount of isopropyl alcohol; subsequently dispersed on a glass substrate.…”

“…This increases the electrical conductivity of the material and thus reduce the width of the depletion region. As a result of this reaction, the sensor reaches a steady state resistance (R g ) [7].…”

“…The techniques employed for the synthesis of WO 3 nanostructures are also manifold. We have already reported in our previous work [7] that the precipitation method is a flexible technique for preparing monoclinic WO 3 NPs with optimal thermal treatment (823 K). Since pure WO 3 contributes to a limited extent; it is necessary to improve the sensing properties through various strategies.…”