Nanostructuring of pseudocapacitive MnFe 2 O 4 /Porous rGO electrodes in capacitive deionization

Hammad Younes, Florent Ravaux, Nabil El Hadri, Linda Zou

Research output: Contribution to journalArticlepeer-review

57 Scopus citations

Abstract

Capacitive deionization (CDI) has been used to remove salt ions with carbon electrodes by the electrical double layer (EDL) mechanism. Other non-carbon materials based on pseudocapacitive mechanism resulting from faradaic reactions with fast electrosorption/desorption properties have emerged as new promising electrode materials. Until now, pseudocapacitive behavior was limited to thin film electrodes with nanometer thickness and was not yet suitable for practical application. In this work, we employed a two-times of hydrothermal synthesis process constructing MnFe 2 O 4 /Porous rGO (MFO/PrGO) nanostructure as pseudocapacitive electrodes. In this carefully designed architecture, the dense structure of MFO/rGO prepared by first-time hydrothermal process provided good connections of MFO nanoparticle with rGO framework for efficient redox charge transfer; the chemically-etched porous rGO used in the second-time hydrothermal process offered hierarchical pores for easier access of the electrode materials, both contributed in enhanced pseudocapacitive electrosorption. HRTEM verified the MnFe 2 O 4 spinel structure and measured the inter-planar lattice parameter which functioned for ion intercalating in and out of the electrode. The MFO/PrGO electrode resulted in 237 F/g in electrosorption of ions from aqueous solution which was higher than the MFO only electrode. Finally, in the CDI experiment, the great salt electrosorption capacity of 8.9 mg/g and 100% regeneration in multiple cycles were achieved by the MFO/PrGO nanocomposite electrode. These results paved the way for using spinel compounds and graphene nanocomposite electrodes for efficient electrosorption and desalination.

Original languageBritish English
Pages (from-to)1-8
Number of pages8
JournalElectrochimica Acta
Volume306
DOIs
StatePublished - 20 May 2019

Keywords

  • Capacitive deionization
  • Nanostructuring
  • Porous rGO
  • Pseudocapacitve electrode
  • Spinel compound

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