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Design-controlled synthesis of IrO 2 sub-monolayers on Au nanoflowers: marrying plasmonic and electrocatalytic properties

DOI: 10.1039/D0NR01875A DOI Help

Authors: Isabel C. De Freitas (Universidade de São Paulo) , Luanna S. Parreira (Universidade de São Paulo) , Eduardo C. M. Barbosa (Universidade de São Paulo) , Barbara A. Novaes (Universidade de São Paulo) , Tong Mou (The University of Oklahoma) , Tiago. V. Alves (Universidade Federal da Bahia Rua Barão de Jeremoabo) , Jhon Quiroz (University of Helsinki) , Yi-chi Wang (University of Helsinki) , Thomas J. Slater (University of Manchester; Diamond Light Source) , Andrew Thomas (University of Manchester) , Bin Wang (The University of Oklahoma) , Sarah J. Haigh (University of Manchester) , Pedro H. C. Camargo (Universidade de São Paulo; University of Helsinki)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nanoscale , VOL 118

State: Published (Approved)
Published: April 2020

Open Access Open Access

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.

Subject Areas: Chemistry

Technical Areas: