The University of Southampton
University of Southampton Institutional Repository

Mean intrinsic activity of single Mn sites at LaMnO3 nanoparticles towards the oxygen reduction reaction

Mean intrinsic activity of single Mn sites at LaMnO3 nanoparticles towards the oxygen reduction reaction
Mean intrinsic activity of single Mn sites at LaMnO3 nanoparticles towards the oxygen reduction reaction
LaMnO3 has been identified as one of the most active systems towards the 4‐electron oxygen reduction reaction (ORR) under alkaline conditions, although the rationale for its high activity in comparison to other perovskites remains to be fully understood. LaMnO3 oxide nanoparticles are synthesised by an ionic‐liquid based method over a temperature range of 600 to 950 °C. This work describes a systematic study of the LaMnO3 properties, from bulk to the outermost surface layers, as a function of the synthesis temperature in order to relate them to the ORR activity. The bulk and surface composition of the particles are characterised by transmission electron microscopy, X‐ray diffraction, X‐ray absorption and X‐ray photoemission spectroscopies (XPS), as well as low‐energy ion scattering spectroscopy (LEIS). The particle size and surface composition are strongly affected by temperature, although the effect is non‐monotonic. The number density of redox active Mn sites is obtained from electrochemical measurements, and correlates well with the trends observed by XPS and LEIS. ORR studies of carbon‐supported LaMnO3 employing rotating ring‐disk electrodes show a step increase in the mean activity of individual surface Mn sites for particles synthesised above 700 °C. Our analysis emphasises the need to establish protocols for quantifying turn‐over frequency of single active sites in these complex materials to elucidate appropriate structure‐activity relationships.
electrocatalysis, Kinetics, Oxygen reduction reaction, LaMnO3, perovskite nano-particles
Celorrio, Veronica
5ebb7fb5-a74c-4872-9795-5830dc915d0b
Calvillo, Laura
05ff21ed-97ce-4ea4-9b73-f4c181be59b0
van den Bosch, Celeste
62cc6852-25e8-451e-a864-2e4d1128bf37
Granozzi, Gaetano
e1561b71-a42d-4c72-9028-3fb07183fceb
Aguadero, Ainara
d0665a8f-70ce-4c7e-8c45-98fac118f69f
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Fermin, David J.
3bfcec3e-75fc-487b-9367-ea8c805f4c0d
Celorrio, Veronica
5ebb7fb5-a74c-4872-9795-5830dc915d0b
Calvillo, Laura
05ff21ed-97ce-4ea4-9b73-f4c181be59b0
van den Bosch, Celeste
62cc6852-25e8-451e-a864-2e4d1128bf37
Granozzi, Gaetano
e1561b71-a42d-4c72-9028-3fb07183fceb
Aguadero, Ainara
d0665a8f-70ce-4c7e-8c45-98fac118f69f
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Fermin, David J.
3bfcec3e-75fc-487b-9367-ea8c805f4c0d

Celorrio, Veronica, Calvillo, Laura, van den Bosch, Celeste, Granozzi, Gaetano, Aguadero, Ainara, Russell, Andrea E. and Fermin, David J. (2018) Mean intrinsic activity of single Mn sites at LaMnO3 nanoparticles towards the oxygen reduction reaction. ChemElectroChem. (doi:10.1002/celc.201800729).

Record type: Article

Abstract

LaMnO3 has been identified as one of the most active systems towards the 4‐electron oxygen reduction reaction (ORR) under alkaline conditions, although the rationale for its high activity in comparison to other perovskites remains to be fully understood. LaMnO3 oxide nanoparticles are synthesised by an ionic‐liquid based method over a temperature range of 600 to 950 °C. This work describes a systematic study of the LaMnO3 properties, from bulk to the outermost surface layers, as a function of the synthesis temperature in order to relate them to the ORR activity. The bulk and surface composition of the particles are characterised by transmission electron microscopy, X‐ray diffraction, X‐ray absorption and X‐ray photoemission spectroscopies (XPS), as well as low‐energy ion scattering spectroscopy (LEIS). The particle size and surface composition are strongly affected by temperature, although the effect is non‐monotonic. The number density of redox active Mn sites is obtained from electrochemical measurements, and correlates well with the trends observed by XPS and LEIS. ORR studies of carbon‐supported LaMnO3 employing rotating ring‐disk electrodes show a step increase in the mean activity of individual surface Mn sites for particles synthesised above 700 °C. Our analysis emphasises the need to establish protocols for quantifying turn‐over frequency of single active sites in these complex materials to elucidate appropriate structure‐activity relationships.

Text
Celorrio_LMO_MS_accepted - Accepted Manuscript
Restricted to Repository staff only until 22 September 2019.
Request a copy
Text
Figures
Restricted to Repository staff only until 22 September 2019.
Request a copy
Text
Supporting Information
Restricted to Repository staff only until 22 September 2019.
Request a copy

More information

Accepted/In Press date: 22 June 2018
e-pub ahead of print date: 10 July 2018
Published date: 12 October 2018
Keywords: electrocatalysis, Kinetics, Oxygen reduction reaction, LaMnO3, perovskite nano-particles

Identifiers

Local EPrints ID: 421734
URI: https://eprints.soton.ac.uk/id/eprint/421734
PURE UUID: d80c4180-c71e-4eda-8d0a-fe6641aea6b5
ORCID for Andrea E. Russell: ORCID iD orcid.org/0000-0002-8382-6443

Catalogue record

Date deposited: 26 Jun 2018 16:30
Last modified: 14 Mar 2019 01:49

Export record

Altmetrics

Contributors

Author: Veronica Celorrio
Author: Laura Calvillo
Author: Celeste van den Bosch
Author: Gaetano Granozzi
Author: Ainara Aguadero
Author: David J. Fermin

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×