Preparation of palladium oxide nanoparticles supported on tin oxide nanofibers via modified electrospinning for ultra-low ppb NO2 detection

Abstract

Herein, we describe the fabrication of a gas sensor based on self ordered SnOx nanofibers decorated with PdOx nanoparticles by using a simple, flexible and scalable approach. The sensing material was synthesized and integrated onto screen printed microceramic platform using modified electrospinning. Material morphology and structure were addressed by Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM) and X-Ray Diffraction analysis (XRD). Moreover, X-ray Photoelectron Spectroscopy (XPS) confirmed the successful grafting of palladium ions onto the nanofiber outer wall.In an attempt to fully replicate the real working conditions of a gas sensor, the electrical measurements were performed upon exposure of the sensor to different concentrations of NO2 diluted in humid air. PdOx@SnOx sensor demonstrated a remarkable sensitivity towards NO2 with good linearity and detection limit around 10 ppb under humid air. Furthermore, the sensor exhibited an ultra weak cross sensitivity towards interfering air pollutants present at high ppm level such as CO and NH3 at 325 °C. For comparison, the reference sensor based on bare SnOx showed a degraded response towards tested gases under humid ambient. This proves the potential of the hybrid sensor preparation protocol regarding its future application for the detection and quantification of low levels of NO2 in air.