NiFe layered double hydroxides synthesized based on solvent properties as anode catalysts for enhanced oxygen evolution reaction

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 480; p. 147789
• Main Authors: Gu, Yoonhi, Park, Deok-Hye, Kim, Min-Ha, Byeon, Jeong-Hyeon, Lim, Da-Mi, Park, Seon-Ha, Kim, Ji-Hwan, Jang, Jae-Sung, Park, Kyung-Won
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-01-2024
• Subjects: Anion exchange membrane water electrolysis; Anode catalyst; NiFe layered double hydroxide; Oxygen evolution reaction; Solvent ratio-adjusted hydrothermal synthesis; Oxygen evolution reaction; Anode catalyst; Solvent ratio-adjusted hydrothermal synthesis; Anion exchange membrane water electrolysis; NiFe layered double hydroxide
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2023.147789

For a high-performance OER, we synthesized NiFe LDH as an anode catalyst with a high specific surface area and electrical conductivity using a solvent ratio-adjusted hydrothermal method.
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•We synthesized NiFe LDH using a solvent ratio-adjusted hydrothermal method.•The oxygen vacancies produced by alcoholysis promote the charge transfer rate.•The interplanar distance was increased by inserting nitrate in NiFe LDH.•WE 55 synthesized at a proper ratio of water and ethanol showed the best performance.
NiFe layered double hydroxides (LDH) with their high specific surface areas have been used as alternatives to noble metal catalysts for the oxygen evolution reaction (OER) in anion exchange membrane water electrolysis. However, for bulk LDH structures, relatively narrow interplanar distances can lead to the slow diffusion of OH− and the induction a local acidic atmosphere, resulting in catalyst corrosion. In this study, we synthesize solvent (water and ethanol) ratio-adjusted NiFe LDH anode catalysts to enhanced the OER. Results show that the catalyst prepared at a 5:5 ratio of water and ethanol (WE 55) delivers a low overpotential of 310 mV at 50 mA cm−2, Tafel slope of 40.5 mV dec−1, and 100 h-stability in a half-cell test, and a high current density of 744.2 mA cm−2 at 1.8 V and 70 °C in a single-cell test. WE 55 exhibits a manipulated oxygen vacancy and a substantially high specific surface area of ∼ 164.5 m2 g−1, leading to improved charge transfer and mass transport rates.