Effects of Chemical State of the Pd Species on H2 Sensing Characteristics of PdOx/SnO2 Based Chemiresistive Sensors.

Tianjiao Qi,Xi Yang,Jie Sun,Ji Zuo,Fanfan Yan

doi:10.3390/s19143131

Tianjiao Qi, Xi Yang + Show 3 more

Open Access

https://doi.org/10.3390/s19143131

Copy DOI

Abstract

In this paper, the PdOx nanoparticles modified SnO2 are prepared using sputtering and wet chemical methods. The SnO2 nanoparticles are separately added to a concentration of 0.75% to 10% PdCl2 to obtain a PdCl2/SnO2 composite material, which is calcined for 1 to 2 h at the temperatures of 120 °C, 250 °C, 450 °C and 600 °C. The PdOx/SnO2 nanocomposite was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). Microstructural observations revealed PdOx with different chemical states attached to the surface of SnO2. Hydrogen response change tests were performed on the obtained PdOx/SnO2 gas sensing materials. The results show that the high gas sensing performance may be attributed to the contribution of the PdOx-loaded SnO2. In hydrogen, the best sensitivity response was attained at 80 °C, which is 60 times that of pristine SnO2. It clarifies the role of PdOx in the gas sensing mechanisms.

Highlights

Hydrogen is expected to become a green and renewable energy source, in response to air pollution, global warming and the increasing shortage of fossil fuels
We studied the sensing behavior of the PdOx / SnO2 sensor at different annealing temperatures that obtained different chemical states of Pd toward H2 at the optimal operating temperature
SnO2 nanoparticles loaded with PdOx at different annealing temperatures have been systemically studied for H2 -sensing applications

Summary

Introduction

Hydrogen is expected to become a green and renewable energy source, in response to air pollution, global warming and the increasing shortage of fossil fuels. This light and odorless gas is highly flammable, and the leakage can result in disastrous consequences, such as explosions [1]. As a typical n-type wide bandgap semiconductor, tin oxide (SnO2 , with a bandgap (Eg ) of 3.6 eV at 300 K) has been highly investigated due to its high gas sensitive activity to a wide variety of gases [6] Their poor selectivity creates a huge limitation for achieving wide applications. The high working temperature (usually superior to 200 ◦ C) requires high power consumption, and restricts the integration and the use of materials for device assembling [7]

Methods

Results

Conclusion