Fine-tuning nanoflower-like Fe/Co hybrids with high content oxyhydroxide accelerating oxygen evolution kinetics

• Published in: Journal of colloid and interface science 2024-09, Vol.670, p.124-131
• Main Authors: Wang, Lixia, Huang, Jia, Gan, Qiuping, Huang, Jiasui, Hu, Xinran, Liu, Dongcheng, Taylor Isimjan, Tayirjan, Yang, Xiulin
• Format: Article
• Language: English
• Subjects: Electrocatalyst; Electrodeposition; Overall water splitting; Oxygen evolution reaction
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2024.05.034

A nanoflower-like FeCo-hydro(oxy)oxide catalyst is successfully fabricated using a simple one-step electrodeposition technique. The optimized Fe9-Co1 catalyst exhibits good performance for OER (η50= 222 mV) and overall water splitting (1.73 V@100 mA cm−2). The reconstructed FeOOH/CoOOH serves as the real active sites, and a small amount of Co species can optimize the activation energies between the active sites and oxygen-containing intermediates, thereby improving the performance of water splitting. [Display omitted] •A nanoflower-like FeCo hybrids is synthesized by a facile electrodeposition method.•The Fe9-Co1 catalyst delivers a good OER activity (η50 = 222 mV) and stability.•The reconstructed FeOOH/CoOOH serves as the real active sites during OER process.•The synergy between Co and Fe species reduces the activation energies with intermediates and improves OER activity. Iron hydroxide (FeOOH) is a potential active component in iron-based electrocatalysts for water electrolysis. However, its catalytic performance is constrained by its slow oxygen evolution reaction (OER) kinetics. Herein, we synthesized a nanoflower-like FeCo-hydro(oxy)oxides composite with tunable Fe/Co ratios (Fex-Coy) on nickel foam (NF) via a one-step electrodeposition technique. This method allows for precise control over the morphology and composition of the hybrid nanoflowers. The optimized Fe9-Co1 discloses favorable OER performance with a low overpotential of 222 mV at 50 mA cm−2 and demonstrates good stability exceeding 60 h at 10 mA cm−2. Further, an assembled Fe9-Co1(+)||Pt/C(−) dual-electrode configuration achieves a low cell voltage of 1.73 V at the current density of 100 mA cm−2 for water splitting, with long-term stability for 70 h and minimal degradation. Studies indicate that the distinctive nanoflower morphology of Fe9-Co1 enhances active site exposure, while both FeOOH and reconstructed CoOOH serve as catalytic centers, contributing to the observed OER performance. This work introduces a facile approach for synthesizing OER electrocatalysts, underscoring the role of the high-valence state of Fe/Co as active sites in the OER process.