Optimization of Ni−Co−Fe-Based Catalysts for Oxygen Evolution Reaction by Surface and Relaxation Phenomena Analysis

Rinat Attias, Kalimuthu Vijaya Sankar, Kapil Dhaka, Wenjamin Moschkowitsch, Lior Elbaz, Maytal Caspary Toroker, Yoed Tsur

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Trimetallic double hydroxide NiFeCo−OH is prepared by coprecipitation, from which three different catalysts are fabricated by different heat treatments, all at 350 °C maximum temperature. Among the prepared catalysts, the one prepared at a heating and cooling rate of 2 °C min−1 in N2 atmosphere (designated NiFeCo−N2-2 °C) displays the best catalytic properties after stability testing, exhibiting a high current density (9.06 mA cm−2 at 320 mV), low Tafel slope (72.9 mV dec−1), good stability (over 20 h), high turnover frequency (0.304 s−1), and high mass activity (46.52 A g−1 at 320 mV). Stability tests reveal that the hydroxide phase is less suitable for long-term use than catalysts with an oxide phase. Two causes are identified for the loss of stability in the hydroxide phase: a) Modeling of the distribution function of relaxation times (DFRT) reveals the increase in resistance contributed by various relaxation processes; b) density functional theory (DFT) surface energy calculations reveal that the higher surface energy of the hydroxide-phase catalyst impairs the stability. These findings represent a new strategy to optimize catalysts for water splitting.

Original languageEnglish
Pages (from-to)1737-1746
Number of pages10
JournalChemSusChem
Volume14
Issue number7
DOIs
StatePublished - 9 Apr 2021

Bibliographical note

Publisher Copyright:
© 2021 Wiley-VCH GmbH

Keywords

  • density functional calculations
  • electrocatalysis
  • hydroxides
  • porous materials
  • relaxation processes

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