The Disputation will be live streamed for everyone else.
The livestream will be activated 15 minutes before the Defence starts.
Trial lecture
April 19th, 10:15 AM, Auditorium 3, Chemistry building
Trial lecture title:
“Kinetics of dissociative adsorption of gaseous species on oxides - fundamentals and applications.”
The trial lecture will be live streamed for everyone else.
The livestream will be activated 15 minutes before the trial lecture starts.
Kreeringssammendrag/Conferral summary
Avhandlingen beskriver en studie av adsorpsjon og dissosiasjon av vann og resulterende protonisk overflateledning i porøse keramiske oksider. Ny nomenklatur og modeller som er utviklet i dette arbeidet muliggjør kvantitativ tolkning av og en forutsigbar rolle for protonisk overflateledning i elektrokjemiske og fotoelektrokjemiske celler, fuktighetssensorer og heterogen katalyse.
Main research findings
The present work provides a fundamental and methodological framework for parameterisation of the thermodynamics and kinetics involved in surface protonic conduction of porous ionic oxides. A novel nomenclature for defect surface species is introduced. The surface protonic conductances have been estimated where various proton migration routes were considered. A brick layer model is developed that connects surface conductance with macroscopic sample conductivity via microstructural parameters. This allows quantitative discrimination between types of adsorption and surface transport in the different water layers on oxide surfaces, supported by water vapour partial pressure dependencies and enthalpies of adsorption and conductivity. The enthalpies for protonic surface mobility for oxides decrease systematically with lower temperatures (higher relative humidity) as the water layers grow in coverage and thickness and protons go from jumping between surface oxide ions to jumping between loosely bonded adsorbed hydroxide ions and water molecules. The findings and models developed in this work contribute to the understanding and control of surface protonics in porous oxides, which is believed to play an important role in electrochemical and photoelectrochemical cells, humidity sensors, and heterogeneous catalysis.
Candidate contact information
ResearchGate: https://www.researchgate.net/profile/Xinwei-Sun-2
E-mail: xinwei.sun@smn.uio.no
Phone: +47 40622018