Magnetic-Field-Induced Electrochemical Performance of a Porous Magnetoplasmonic Ag@Fe3O4 Nanoassembly

Lemma Teshome Tufa; Ki-Jae Jeong; Van Tan Tran; Jaebeom Lee

doi:10.1021/acsami.9b18639

Magnetic-Field-Induced Electrochemical Performance of a Porous Magnetoplasmonic Ag@Fe₃O₄ Nanoassembly

ACS Appl Mater Interfaces. 2020 Feb 5;12(5):6598-6606. doi: 10.1021/acsami.9b18639. Epub 2020 Jan 22.

Authors

Lemma Teshome Tufa^{1

2}, Ki-Jae Jeong³, Van Tan Tran¹, Jaebeom Lee¹

Affiliations

¹ Department of Chemistry , Chungnam National University , Daejeon 34134 , Republic of Korea.
² Department of Chemistry , Adama Science and Technology University , P.O. Box 1888, Adama , Ethiopia.
³ Department of Cogno-Mechatronics Engineering , Pusan National University , Busan 46241 , Republic of Korea.

PMID: 31922383
DOI: 10.1021/acsami.9b18639

Abstract

The Lorentz or Kelvin force generated by an externally applied magnetic field may introduce additional convection of the electrolyte near the working electrode and consequently produces magnetocurrent (MC), which can be attributed to the magnetohydrodynamic (MHD) flow and an extra electrochemical reaction. A magnetoplasmonic (MagPlas) composite of metallic and superparamagnetic nanoparticles (NPs) with a permanent dipole or magnetic moment have additional degree or order, which corresponds to directional correlation to electric and magnetic dipoles. In particular, an ordered self-assembly may boost up the MHD flow on a collectively reactive surface, leading to remarkable electrochemical performance. In this article, a proof-of-concept work explores the effect of the magnetic field on the electrocatalytic activity of the oxygen reduction reaction (ORR) as well as [Fe(CN)₆]^3-/4- redox probes using a precisely controlled three-dimensional (3D) nanostructure of a silver core and a porous magnetic shell (Ag@Fe₃O₄) assembly. Then, the reduction current was carefully monitored in the presence of a magnetic field (B, up to 380 mT), resulting in an extraordinary increment of reduction current (I_R) of [Fe(CN)₆]^3- by 23% and a 1.13-fold high ORR efficiency owing to the additional magnetic field (B_in) from the 3D magnetoplasmonic nanoassembly. The computational simulation explained the plausible mechanism of current enhancement from the MagPlas nanoassembly. From our experimental and computational studies, it is probable that the 3D MagPlas nanoassembly is a unique and efficient catalyst under a low external magnetic field, which would be useful for further biomedical and energy-related applications.

Keywords: electrocatalyst; magnetic field effect; magnetically assembled Ag@Fe3O4 NPs; magnetoplasmonic; mass transport; oxygen reduction reaction (ORR).