Synergistic Effects of Co and Fe on the Oxygen Evolution Reaction Activity of LaCoxFe1−xO3
Open Access
- 8 September 2021
- journal article
- research article
- Published by Wiley in Chemistry – A European Journal
- Vol. 27 (68), 17145-17158
- https://doi.org/10.1002/chem.202102829
Abstract
In a combined experimental and theoretical study we assess the role of Co incorporation on the OER activity of LaCo x Fe 1− x O 3 . Phase pure perovskites were synthesized up to x = 0.300 in 0.025/0.050 steps. HAADF STEM and EDX analysis points towards FeO2 -terminated (001)-facets of LaFeO3, in accordance with the stability diagram obtained from density functional theory calculations with a Hubbard U term (DFT+ U ). Linear sweep voltammetry shows a reduction of the OER overpotential and a nonmonotonic trend wtih x , with double layer capacitance measurements indicating an intrinsic nature of activity. This is supported by DFT+ U results that show reduced overpotentials for both Fe and and Co reaction sites with the latter reaching values of 0.32-0.40 V, ~0.3 V lower than for Fe. This correlates with a stronger reduction of the binding energy difference of the *O and *OH intermediates towards an optimum value of 1.6 eV for x =0.25, the OH deprotonation being the potential limiting step in most cases. Significant variations of the magnetic moments of both surface and subsurface Co and Fe during the OER demonstrate that the beneficial effect is a result of a concerted action involving many surrounding ions, which extends the concept of the active site.Funding Information
- Deutsche Forschungsgemeinschaft (388390466)
- Mercator Research Center Ruhr (Pe-2018-0034)
This publication has 73 references indexed in Scilit:
- Three-dimensionally ordered macroporous LaCoxFe1−xO3 perovskite-type complex oxide catalysts for diesel soot combustionCatalysis Today, 2010
- Oxidation energies of transition metal oxides within theframeworkPhysical Review B, 2006
- High-precision finite-size scaling analysis of the quantum-critical point ofHeisenberg antiferromagnetic bilayersPhysical Review B, 2006
- Co0 from partial reduction of La(Co,Fe)O3 perovskites for Fischer–Tropsch synthesisCatalysis Today, 2003
- Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+U studyPhysical Review B, 1998
- Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis setPhysical Review B, 1996
- Projector augmented-wave methodPhysical Review B, 1994
- Ab initiomolecular dynamics for liquid metalsPhysical Review B, 1993
- Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenidesActa Crystallographica Section A, 1976
- Special points for Brillouin-zone integrationsPhysical Review B, 1976