se9b00521_si_001.pdf (717.38 kB)
Direct Operando Spectroscopic Observation of Oxygen Vacancies in Working Ceria-Based Gas Sensors
journal contribution
posted on 2019-05-22, 00:00 authored by Ann-Kathrin Elger, Julian Baranyai, Kathrin Hofmann, Christian HessMetal-oxide semiconductors are of
great interest for gas-sensing
applications. We provide new insights into the mode of operation of
ceria-based gas sensors during ethanol gas sensing using combined operando Raman–gas-phase FTIR spectroscopy. Visible
Raman spectroscopy is employed to monitor the presence of oxygen vacancies
in ceria via F2g mode softening, while simultaneously recorded
FTIR spectra capture the gas-phase composition. Such an experimental
approach allowing the direct observation of oxygen vacancies in metal-oxide
gas sensors has not been reported in the literature. By systematically
varying the gas atmosphere and temperature, we can relate the sensor
response to the spectroscopic signals, enabling us to obtain new fundamental
insight into the functioning of metal-oxide semiconductor gas sensors,
as well as their differences from heterogeneous catalysts.