Open AccessOxygen Evolution on Iron Oxide Nanoparticles: The Impact of Crystallinity and Size on the Overpotential
Author(s) -
Zhongbin Zhuang,
Stephen A. Giles,
Glen R. Jenness,
Reza Abbasi,
Xi Chen,
Bo Wang,
Dionisios G. Vlachos,
Yushan Yan
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/abef47
Subject(s) - overpotential , oxygen evolution , nanoparticle , oxide , crystallinity , water splitting , materials science , chemical engineering , amorphous solid , inorganic chemistry , nanotechnology , chemistry , catalysis , electrochemistry , metallurgy , photocatalysis , electrode , biochemistry , organic chemistry , composite material , engineering
The oxygen evolution reaction (OER) is a critical reaction in electrolysis and photoelectrolysis of water to generate and store clean energy. Therefore, the development of low-cost and efficient electrocatalysts for the OER is of great scientific and technological importance. Although promising iron oxide-based electrocatalysts have been recently developed for the OER, an in-depth experimental and theoretical analysis of the OER mechanism on iron oxide-based electrocatalysts is still needed to provide guidelines to optimize the performance of iron oxide-based electrocatalysts further. To address this need, we synthesized a series of monodisperse iron oxide nanoparticles to analyze their intrinsic OER activities. Using nanoparticles of the same size but different crystallinity, we show that amorphous iron oxide nanoparticles have better OER activity than crystalline ones. The size effect studies further revealed that the edge/defect sites are the active sites for the OER. Density functional theory calculations demonstrated that the edge/defect sites provide bridge sites to adsorb OER intermediates, resulting in low OER overpotential. These calculations confirm that the high OER activity of amorphous nanoparticles results from a high concentration of defect sites on their surface. These results provide novel strategies to increase the performance of iron oxide-based and likely other oxide-based OER electrocatalysts.