Unravelling the synergy of oxygen vacancies and gold nanostars in hematite for the electrochemical and photoelectrochemical oxygen evolution reaction
File(s)Hematite-paper.pdf (2.87 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
The development of hematite-based electrocatalysts (EC) and photoelectrocatalysts (PEC) for oxygen evolution reaction (OER) is highly promising on account of the low-cost and favorable chemical properties. Herein, we report a unique inverse opal framework hematite-based bi-functional catalyst for both EC and PEC water oxidation in alkaline media. Under the combined action of oxygen vacancies (Vo) and gold nanostars (AuNSs) on hematite, the catalyst exhibited excellent activity and stability on both EC and PEC. The composite showed superior electrocatalytic performance for OER with a low overpotential of 281 mV at 10 mA cm−2. Density functional theory (DFT) studies reveal that the coverage of Vo controls the d-band center of surface Fe sites, and the OER activity displays a volcano relationship with the Vo coverage. The addition of gold nanoparticles on the hematite with low Vo coverage improves the adsorption strength of oxygen-containing intermediates to the optimal point and increases the OER activity. Furthermore, the as-prepared photoanode exhibits a ∼3.13 fold increase in current (1.46 mA cm−2) at 1.23 V versus RHE. It is proposed that Vo promotes bulk conductivity and surface catalysis and exhibits reduced activation energy under high light intensity. AuNSs efficiently inhibits the bulk recombination and improves carrier concentration because of the Fermi level equilibration and plasmonic resonance, and the surface catalysis compensates the deterioration of interfacial recombination of carriers induced by Vo, playing a synergistic role.
Date Issued
2022-04-01
Date Acceptance
2022-01-15
Citation
Nano Energy, 2022, 94, pp.1-10
ISSN
2211-2855
Publisher
Elsevier BV
Start Page
1
End Page
10
Journal / Book Title
Nano Energy
Volume
94
Copyright Statement
Crown Copyright © 2022 Published by Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
https://www.sciencedirect.com/science/article/pii/S2211285522000532?via%3Dihub
Subjects
0303 Macromolecular and Materials Chemistry
0912 Materials Engineering
1007 Nanotechnology
Publication Status
Published
Article Number
ARTN 106968
Date Publish Online
2022-01-19