SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 25: Poster: Metal Substrates
O 25.1: Poster
Montag, 27. März 2023, 18:00–20:00, P2/EG
Ab initio design of Pt-Ir based novel bifunctional electrocatalysts for fuel cell applications — •Halil Ibrahim Sözen1, Mehtap Oezaslan2, and Thorsten Klüner1 — 1Institute of Chemistry, Carl-von-Ossietzky University of Oldenburg, D-26129 Oldenburg, Germany — 2Technische Universität Braunschweig, Braunschweig 38106, Germany
Electric vehicles powered by polymer electrolyte membrane fuel cells (PEMFC) have a great potential to reduce a large portion of CO2 emissions from the transportation sector and facilitate the advent of the hydrogen economy worldwide. However, highly dynamic conditions during the operation of PEMFC in the heavy-duty sector cause hydrogen starvation at the anode electrode, resulting in cell reversal events (< -1.5 V) and therefore carbon oxidation reaction (COR). In this work, we aimed to develop novel bifunctional electrocatalysts for the anode electrode based on Pt-Ir alloys. Our innovative approach involves unifying two functionalities, the hydrogen oxidation reaction (HOR) and oxygen evolution reaction (OER), as an alternative reaction for proton and electron formation to the COR in only one nanoparticle on the same support material. Density functional theory (DFT) based chemisorption energies of H*, O*, OH*, H2O* and OOH* are reported with the effect of hydroxyl species presence and the effect of pH. Calculated chemisorption energies are implemented to model HOR and OER and plot Gibbs free energy diagrams. Various surfaces such as Pt(111), Pt3Ir(111), PtIr(111) and Ir(111) have been considered for electrocatalytic reactions and their relative performance is compared.