Detection mechanism studies of SO2 on Pt / SiO2 system
(English)Manuscript (preprint) (Other academic)
Experiment was performed with Pt-gate SiC-FET sensors to study the detection mechanism of the sensors. The sensing measurement showed that oxygen influenced the response quite strongly. The sensor response became larger in the presence of oxygen. Experiment with mass spectroscopy indicated the formation of SO3 during the sensing measurement. Further experiment with DRIFT spectroscopy showed the formation of sulfate species on the oxide surface, accompanied by the disappearance of the silanol groups. An explanatory model was built based on quantum-chemical calculations. The results strengthened the experimental results by showing that it was more energetically favorable for SO2 to oxidize into SO3 before being adsorbed on the oxide surface. It was also observed that the overall adsorption reaction was exothermic, the activation energy for the SO2 oxidation was 48,75 kJ/mol, and the rate limiting step was the desorption of SO3 from the Pt surface.
SO2 sensors, SiC-FET, Pt, detection mechanism, quantum chemical calculations
IdentifiersURN: urn:nbn:se:liu:diva-106214OAI: oai:DiVA.org:liu-106214DiVA: diva2:714648