Surface exsolved NiFeOx nanocatalyst for enhanced alkaline oxygen evolution catalysis

• Published in: Applied surface science 2024-07, Vol.662, p.160134, Article 160134
• Main Authors: Jeong, Hyeongwon, Jang, Hyunwoo, Han Kim, Yo, Kim, Minwoo, Kang, Youngho, Myung, Jae-ha
• Format: Article
• Language: English
• Subjects: Catalyst; Exsolution; Oxygen electrode; Oxygen evolution reaction; Perovskite
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2024.160134

[Display omitted] •Surface exsolved nano NiFeOX catalyst is prepared on a perovskite surface via in-situ exsolution method.•The Ni and Fe co-doping enabled the control of particle size, distribution, and chemical composition.•The DFT result indicate the that NiFeOx nano particles synergistically reduced free energy for the formation of oxygen double bonding (O*) and oxyhydroxide (OOH*) ions. A synergistically improved alkaline oxygen evolution catalyst of the NiFeOx nanoalloy oxide structure is introduced using an in-situ exsolution method. The separately doped Ni and Fe ions are exsolved on the surface of the perovskite as homogeneously distributed NiFeOx oxide alloy catalysts via following reduction and oxidation processes. The incorporation of additional Fe into the surface embedded NiFeOx catalyst improved the inherent oxygen evolution reaction (OER) property with fast reaction kinetics. Density functional theory (DFT) result indicates the lowest OER overpotential of NiFeOx catalyst is originated from the reduced energy barrier of surface *O formation from *OH group. The NiFeOx exsolved catalyst shows the smallest overpotential of 0.49 V (j = 10 mA∙cm−2) and Tafel slope (93 mV∙dec-1), compared with that of single NiO (0.54 V, 132 mV∙dec-1) and Fe3O4 catalyst. This study provides an effective method for developing nanosized OER catalysts for various energy conversion and storage electrode materials.