In situ regulating intimately connected heterostructure by decomposition of solid solution oxides toward high-efficient water oxidation

• Published in: Rare metals 2024-04, Vol.43 (4), p.1557-1569
• Main Authors: Zhang, Shao-Fei, Yin, Xiao-Lu, Wang, Jin, Kang, Jian-Li, Li, Tian-Tian, Sun, Jin-Feng, Meng, Yong-Qiang, Wang, Jian-Jiang, Wang, Dian-Long, Qin, Kai-Qiang
• Format: Article
• Language: English
• Subjects: Biomaterials; Chemistry and Materials Science; Cobalt ferrites; Decomposition; Density functional theory; Electrocatalysts; Electrodes; Electrolysis; Electronegativity; Energy; Heterojunctions; Heterostructures; Materials Engineering; Materials Science; Metal foams; Metallic Materials; Nanoscale Science and Technology; Nickel oxides; Original Article; Oxidation; Oxygen enrichment; Oxygen evolution reactions; Physical Chemistry; Reaction kinetics; Solid solutions
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-023-02536-1

Heterogeneous interfaces produced by inter-domain interactions on a nanoscale performs a crucial role in boosting the properties of an electrocatalyst toward oxygen evolution reaction (OER) process. Herein, a series of dual-phase electrodes with intimately connected heterointerfaces are prepared by in situ decomposing solid solution oxide of Ni x Co y Fe 100− x − y O, which grew on Ni foam massively via an ultrafast combustion approach. Particularly, with high-reaction kinetics caused by the reduction treatment at 450 °C, the less electronegative Fe and Co are more oxyphilic than Ni, which facilitated their co-exsolution and formation of CoFe 2 O 4 /NiO oxide with enriched oxygen vacancies. Benefiting from the nanoporous framework, heterojunction structure, and oxygen defects, the self-supporting electrodes present rapid charge/mass transmission and provide abundant active sites for OER. The optimized sample (R-SNCF4.5) shows low overpotentials of 226 and 324 mV at 10 and 100 mA·cm −2 , a small Tafel slope (46.7 mV·dec −1 ), and excellent stability. The assembled R-SNCF4.5//Pt/C/NF electrolyzer demonstrates continuous electrolysis over 50 h at a current density of 10 mA·cm −2 , under 1.51 V. Density functional theory (DFT) calculations verify that the strong electronic modulation plays a critical part in the CoFe 2 O 4 /NiO hybrid by lowering the energy barriers for the rate-determining steps, and Fe sites are the most active OER sites. Graphical abstract