CO sensing properties and mechanism of Pd doped SnO2 thick-films
Journal
Applied Surface Science
Journal Volume
428
Pages
207-217
Date Issued
2018
Author(s)
Abstract
Pd doped SnO 2 nano-particles were synthesized using co-precipitation method. The resistances of the samples first decrease and then increase, which maybe influenced by the Pd doping and temperature effect. The CO response of SnO 2 was improved by doping with Pd. At low temperature range, the response decreases with increasing of operating temperature, which was caused by the physical adsorption. At higher operating temperature (160–400 °C), the response of Pd doped SnO 2 for CO increases at first, undergoes a maximum at 260 °C, and finally drops. The 1.5 wt.% PdO doping SnO 2 was verified to be significantly sensitive. The largest gas sensitive response of 6.59 was found at 260 °C in 400 ppm CO atmosphere. For 200 ppm CO, the response and recovery time were about 43 s and 10 s, respectively. The possible CO sensing mechanisms for Pd doped SnO 2 sensors were investigated with first principles calculations. The calculation results showed that CO molecule can grab O from the pre-adsorbed oxygen on Pd 4 cluster or the PdO cluster on the SnO 2 (110) surface forming CO 2 . These processes may play important role in CO sensing for Pd doped SnO 2 . The calculated result is a good explanation of the experimental observation.
SDGs
Type
journal article