Self-supporting nanosheet electrode for efficient oxygen evolution in a wide pH range: engineering electronic structure of Co3O4 by Fe doping

• Published in: Ionics Vol. 30; no. 6; pp. 3391 - 3401
• Main Authors: Cheng, Xiaobo, Liu, Yanying, Shang, Yunshan, Han, Ningning, He, Guangli, Xu, Zhuang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2024; Springer Nature B.V
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Cobalt oxides; Condensed Matter Physics; Doping; Electrocatalysts; Electrochemistry; Electrodes; Electrolysis; Electrolytes; Electronic structure; Energy Storage; Free energy; Heat of formation; Iron; Nanosheets; Optical and Electronic Materials; Oxygen evolution reactions; Photoelectrons; Pyrolysis; Renewable and Green Energy; Structural stability; Sulfuric acid; Valence; X ray photoelectron spectroscopy; Fe-doping Co; Water electrolysis; Oxygen evolution reaction; Wide pH range; Electronic interaction; O
• ISSN: 0947-7047; 1862-0760
• DOI: 10.1007/s11581-024-05521-5

Developing low-cost and efficient non-precious metal-based electrocatalysts for oxygen evolution reaction (OER) is of great significance for large-scale application of water electrolysis technology. Herein, we present a facile and scalable one-step pyrolysis strategy to fabricate a self-supporting nanosheet electrode involving Fe-doped Co 3 O 4 catalyst (Fe-Co 3 O 4 ) in situ grown on carbon paper for efficient and durable OER catalysis in both alkaline and acidic electrolyte. Results show that doping Fe induces the formation of a uniform nanosheet-like morphology with larger specific surface area that facilitates the full exposure of active sites with accessible contact with electrolyte. Electrochemical test results show that the obtained Fe-Co 3 O 4 exhibits superior activity and high stability for OER catalysis in wide pH range, showing the low overpotentials of 263 and 295 mV in 1.0 M KOH and in 0.5 M H 2 SO 4 , respectively, outperforming commercial IrO 2 . Furthermore, the Fe-Co 3 O 4 also exhibits outstanding electrochemical stability up to 420 h at 10 mA cm −2 and 100 h at 100 mA cm −2 with little change of potential in 1.0 M KOH, and ~ 15-h operation in 0.5 M H 2 SO 4 at 10 mA cm −2 . X-ray photoelectron spectroscopy and DFT theoretical calculations reveal that doping Fe modifies the electronic structure of Co 3 O 4 by decreasing the valence state of Co, which shifts the d band center of Co site upwards and then promotes adsorption intensity of oxygen intermediates, leading to an enhanced OER activity. Furthermore, doping Fe also increases the cobalt vacancy formation energy in Fe-Co 3 O 4 , which inhibits the thermodynamics of Co dissolution, thus improving the structural stability during OER catalysis. This work provides a new insight into the design of high-performance Co 3 O 4 -based non-precious electrocatalysts in both alkaline and acidic electrolyte for the large-scale application of water electrolysis.