Fast Response and Low Detection Limit of Ammonia Sensor Based on WO₃ Nanoparticles-Decorated BiFeO₃ Nanoplates

Abstract

In this paper, an ammonia sensor based on BiFeO ₃ /WO ₃ composites is presented. BiFeO ₃ nanoplates and WO ₃ nanoparticles were prepared by a simple hydrothermal method. The composites were observed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The gas-sensitive properties of the composites and the single material were systematically compared. The experimental results show that the BiFeO ₃ /WO ₃ composites sensor has an excellent response towards ammonia with good long-term stability, short response/recovery time and low detection limit. The gas-sensitive mechanism is further explained that the possible reason for the enhanced gas-sensitive performance is the formation of n-n heterojunctions between BiFeO ₃ nanoplates and WO ₃ nanoparticles. The BiFeO ₃ /WO ₃ composites were shown to be a potential room temperature ammonia sensing material.