Issue 27, 2020

Electroactivation-induced IrNi nanoparticles under different pH conditions for neutral water oxidation

Abstract

Electrochemical oxidation processes can affect the electronic structure and activate the catalytic performance of precious-metal and transition-metal based catalysts for the oxygen evolution reaction (OER). Also there are emerging requirements to develop OER electrocatalysts under various pH conditions in order to couple with different reduction reactions. Herein, we studied the effect of pH on the electroactivation of IrNi alloy nanoparticles supported on carbon (IrNi/C) and evaluated the electrocatalytic activities of the activated IrNiOx/C for water oxidation under neutral conditions. In addition, their electronic structures and atomic arrangement were analyzed by in situ/operando X-ray absorption spectroscopy (XAS) and identical location transmission electron microscopy techniques, showing the reconstruction of the metal elements during electroactivation due to their different stabilities depending on the electrolyte pH. IrNiOx/C activated under neutral pH conditions showed a mildly oxidized thin IrOx shell. Meanwhile, IrNiOx/C activated in acidic and alkaline electrolytes showed Ni-leached IrOx and Ni-rich IrNiOx surfaces, respectively. Particularly, the surface of IrNiOx/C activated under alkaline conditions shows IrOx with a high d-band hole and NiOx with a high oxidation state leading to excellent OER catalytic activity in neutral media (η = 384 mV at 10 mA cm−2) whereas much lower OER activity was reported under alkaline or acid conditions. Our results, which showed that electrochemically activated catalysts under different pH conditions exhibit a unique electronic structure by modifying the initial alloy catalyst, can be applied for the design of catalysts suitable for various electrochemical reactions.

Graphical abstract: Electroactivation-induced IrNi nanoparticles under different pH conditions for neutral water oxidation

Supplementary files

Article information

Article type
Paper
Submitted
14 apr 2020
Accepted
10 jún 2020
First published
11 jún 2020

Nanoscale, 2020,12, 14903-14910

Electroactivation-induced IrNi nanoparticles under different pH conditions for neutral water oxidation

W. H. Lee, J. Yi, H. N. Nong, P. Strasser, K. H. Chae, B. K. Min, Y. J. Hwang and H. Oh, Nanoscale, 2020, 12, 14903 DOI: 10.1039/D0NR02951C

To request permission to reproduce material from this article, 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 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