Issue 45, 2021

Influence of the cobalt content in cobalt iron oxides on the electrocatalytic OER activity

Abstract

Sub 10 nm cobalt ferrite CoxFe3−xO4 (x ≤ 1.75) nanoparticles and cobalt-rich wüstite (Cox/3Fe(1−x)/3)O nanoparticles (x ≥ 2) were synthesized in a solvothermal approach and characterized by powder X-ray diffraction (PXRD), selected area electron diffraction (SAED), transmission electron microscopy (TEM) as well as energy dispersive X-ray spectroscopy (EDX), IR, Raman, and 57Fe-Mössbauer spectroscopy. Their electrocatalytic activity in the oxygen evolution reaction (OER) was evaluated and the active state formation was tracked by operando X-ray absorption spectroscopy (XAS). Our studies demonstrate that the cobalt-rich wüstite (Cox/3Fe(1−x)/3)O nanoparticles underwent a phase-transformation into the spinels CoxFe3−xO4 (x ≥ 2) under the applied OER conditions. The overpotential η10 at 10 mA cm−2, serving as a benchmark for the OER activity of the cobalt ferrite nanoparticles in alkaline media, was lower than that of magnetite Fe3O4 even with low cobalt concentrations, reaching a minimum of 350 mV for Co2.25Fe0.75O4 with a Tafel slope of 50 mV dec−1. Finally, we identified that the catalytic activity is linked to the nanoparticle size as well as to the degree of Co redox activity and change in coordination during OER.

Graphical abstract: Influence of the cobalt content in cobalt iron oxides on the electrocatalytic OER activity

Supplementary files

Article information

Article type
Paper
Submitted
03 août 2021
Accepted
15 oct. 2021
First published
15 oct. 2021
This article is Open Access
Creative Commons BY-NC license

J. Mater. Chem. A, 2021,9, 25381-25390

Influence of the cobalt content in cobalt iron oxides on the electrocatalytic OER activity

S. Saddeler, G. Bendt, S. Salamon, F. T. Haase, J. Landers, J. Timoshenko, C. Rettenmaier, H. S. Jeon, A. Bergmann, H. Wende, B. Roldan Cuenya and S. Schulz, J. Mater. Chem. A, 2021, 9, 25381 DOI: 10.1039/D1TA06568H

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements