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O: Fachverband Oberflächenphysik

O 67: Solid-Liquid Interfaces III: OER, ORR, CO2RR, etc.

O 67.6: Vortrag

Mittwoch, 18. März 2020, 12:00–12:15, WIL C107

DFT+U investigation of the OER activity at LaCoO₃(001) and (110) surfaces — •Achim Füngerlings, Hamidreza Hajiyani, and Rossitza Pentcheva — Department of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg

Using density functional theory calculations including an on-site Hubbard term we explore the oxygen evolution reaction at LaCoO₃ surfaces with different crystallographic orientations. For Co- and La-rich synthesis conditions respectively, the surface phase diagram is dominated by the (001) CoO₂- and LaO- termination over a wide range of oxygen partial pressures. The OER overpotential calculated from the binding energies of the adsorbed intermediates for a Co-reaction site at the CoO₂-terminated (001) surface is 0.70V. To gain more insight, we analyze the changes of electronic structure during the reaction. Thereby, the cobalt’s oxidation state, which is 3+ in the bulk structure and 2+ at the clean surface, becomes 3+ for an adsorbed OH-group and 4+ for the O intermediate. We furthermore explore the effect of A- and B-site substitution on the catalytic activity.

Support by the DFG within the CRC TRR 247, project B4, and a computational grant at the Leibniz-Rechenzentrum are gratefully acknowledged.