Modelling & Simulation
Role of dopants on the performance of metal oxide surfaces for the water oxidation
Hamireza Hajiyani, Faculty of Physics, University of Duisburg-Essen and Center of Nanointegration (CENIDE), Duisburg, GermanyRossitza Pentcheva, Faculty of Physics, University of Duisburg-Essen and Center of Nanointegration (CENIDE), Duisburg, Germany
Based on density functional theory calculations including an on-site Coulomb repulsion term, we explore the oxygen evolution reaction (OER) at transition metal oxide surfaces. We address strategies how to reduce the overpotential during OER as well as modification of the band edge positions through dopants. A systematic variation of dopands throughout the 3d, 4d and 5d series in α-Fe2O3 (0001) surface unravels trends concerning the role of d-band occupation and orbital polarization.
Consistent with previous results, the overpotentials correlate with the binding energy of chemisorbed species within a volcano plot. The underlying mechanisms are discussed by monitoring changes of valence and spin state of the surface cations throughout the intermediate steps of OER. We further generalize our results to other oxide structures such as the spinel.
Support of the DFG within priority program SPP1613, project PE883/9-2 and a computational grant at the Leibniz Rechenzentrum is gratefully acknowledged.