Design-controlled synthesis of IrO2 sub-monolayers on Au nanoflowers: Marrying plasmonic and electrocatalytic properties

De Freitas, I.C., Parreira, L.S., Barbosa, E.C.M., Novaes, B.A., Mou, T., Alves, T.V., Quiroz, J., Wang, Y.-C., Slater, T.J. ORCID: https://orcid.org/0000-0003-0372-1551, Thomas, A., Wang, B., Haigh, S.J. and Camargo, P.H.C. 2020. Design-controlled synthesis of IrO2 sub-monolayers on Au nanoflowers: Marrying plasmonic and electrocatalytic properties. Nanoscale 12 (23) , pp. 12281-12291. 10.1039/d0nr01875a

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Abstract

We develop herein plasmonic–catalytic Au–IrO2 nanostructures with a morphology optimized for efficient light harvesting and catalytic surface area; the nanoparticles have a nanoflower morphology, with closely spaced Au branches all partially covered by an ultrathin (1 nm) IrO2 shell. This nanoparticle architecture optimizes optical features due to the interactions of closely spaced plasmonic branches forming electromagnetic hot spots, and the ultra-thin IrO2 layer maximizes efficient use of this expensive catalyst. This concept was evaluated towards the enhancement of the electrocatalytic performances towards the oxygen evolution reaction (OER) as a model transformation. The OER can play a central role in meeting future energy demands but the performance of conventional electrocatalysts in this reaction is limited by the sluggish OER kinetics. We demonstrate an improvement of the OER performance for one of the most active OER catalysts, IrO2, by harvesting plasmonic effects from visible light illumination in multimetallic nanoparticles. We find that the OER activity for the Au–IrO2 nanoflowers can be improved under LSPR excitation, matching best properties reported in the literature. Our simulations and electrocatalytic data demonstrate that the enhancement in OER activities can be attributed to an electronic interaction between Au and IrO2 and to the activation of Ir–O bonds by LSPR excited hot holes, leading to a change in the reaction mechanism (rate-determinant step) under visible light illumination.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Additional Information:	This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.
ISSN:	2040-3372
Date of First Compliant Deposit:	21 February 2022
Date of Acceptance:	14 April 2020
Last Modified:	04 May 2023 21:15
URI:	https://orca.cardiff.ac.uk/id/eprint/147183

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