Speaker: Jonathan Polfus
Title: Computational studies of electrocatalysts: Surface chemistry of Sr-doped LaMnO3 and diffusion in palladium hydrides
Abstract: Sr-doped LaMnO3 (LSM) is an oxygen reduction reaction electrocatalyst in solid oxide fuel cells and other electrochemical devices. The presence of CO2 and H2O has been reported to promote the oxygen dissociation reaction on LSM surfaces. The role of coadsorption of O2 with H2O or CO2 was investigated by combining density functional theory calculations of the (0 0 1) surface with thermodynamic adsorption models. Palladium exhibits fast dissociation kinetics of molecular hydrogen at its surfaces and high bulk diffusivity of atomic hydrogen, which form the basis for applications as H2 separation membrane and electrocatalyst. Exposure to hydrogen can as well result in a range of structural and microstructural deterioration processes, including embrittlement, cracking and void formation. To bring further insight into these processes, the self-diffusion coefficients of palladium in PdHx (x = 0, 0.25, 0.5, 0.75, 1) were modelled based on the Arrhenius equation.
Due to the present situation with the COVID-19 virus, seminars will be shared between Oslo and Tromsø by using the Zoom virtual meeting system.