Please use this identifier to cite or link to this item: http://hdl.handle.net/10773/37110
Title: Electrochemical reduction of hematite-based ceramics in alkaline medium: challenges in electrode design
Author: Lopes, Daniela V.
Ivanova, Yu. A.
Kovalevsky, Andrei
Sarabando, Artur R.
Frade, Jorge R.
Quina, Margarida J.
Keywords: Cellular ceramics
Hematite
Metallic iron
Zero-valent iron
Cathodic reduction
Issue Date: 10-Dec-2019
Publisher: Elsevier
Abstract: Electrochemical reduction of low-conductive hematite-based ceramics represents a novel approach for iron recovery and waste valorisation. The process itself allows a flexible switching between hydrogen generation and iron reduction, important for the intermittent renewable-energy-powered electrolytic process. The present study focuses on the direct electrochemical reduction of aluminium-containing hematite in strong alkaline media. Within this scope, the reduction mechanisms of porous and dense cathodes, with 60%, 37% and 3% of open porosity, were investigated using different types of electrodes configuration: nickel-foil and Ag-modified nickel-foil supported configuration (cathodes facing or against the counter electrode), and nickel-mesh supported configuration. The efficiency of the iron reduction was compared for different electrode concepts. The results highlight the importance of electrolyte access to the interface between the metallic current collector and ceramic cathode for attaining reasonable electroreduction currents. Both excessively porous and dense ceramic cathodes are hardly suitable for such reduction process, showing a necessity to find a compromise between mechanical strength of the electrode and its open porosity, essential for the electrolyte access.
Peer review: yes
URI: http://hdl.handle.net/10773/37110
DOI: 10.1016/j.electacta.2019.135060
ISSN: 0013-4686
Appears in Collections:CICECO - Artigos
DEMaC - Artigos

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