Electrochemical reduction of hematite-based ceramics in alkaline medium: Challenges in electrode design
authors Lopes, DV; Ivanova, YA; Kovalevsky, AV; Sarabando, AR; Frade, JR; Quina, MJ
nationality International
journal ELECTROCHIMICA ACTA
author keywords Cellular ceramics; Hematite; Metallic iron; Zero-valent iron; Cathodic reduction
keywords IRON PYROELECTROLYSIS; 3-PHASE INTERLINES; OXIDE-FILMS; ELECTROREDUCTION; MONOLITHS; ANODE
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. (C) 2019 Elsevier Ltd. All rights reserved.
publisher PERGAMON-ELSEVIER SCIENCE LTD
issn 0013-4686
year published 2019
volume 327
digital object identifier (doi) 10.1016/j.electacta.2019.135060
web of science category Electrochemistry
subject category Electrochemistry
unique article identifier WOS:000494834100016
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journal impact factor 5.116
5 year journal impact factor 4.857
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