Phosphorus-doped Fe7S8@C nanowires for efficient electrochemical hydrogen and oxygen evolutions: Controlled synthesis and electronic modulation on active sites

• Published in: Journal of materials science & technology Vol. 74; pp. 168 - 175
• Main Authors: Le, Thanh-Tung, Liu, Xiao, Xin, Peijun, Wang, Qing, Gao, Chunyan, Wu, Ye, Jiang, Yong, Hu, Zhangjun, Huang, Shoushuang, Chen, Zhiwen
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30.05.2021
• Subjects: Electrocatalysis; Hydrogen and oxygen evolution reaction; P-doping; Ron sulfide; P-doping; Electrocatalysis; Ron sulfide; Hydrogen and oxygen evolution reaction
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/j.jmst.2020.08.060

Developing low-cost, efficient, and stable non-precious-metal electrocatalysts with controlled crystal structure, morphology and compositions are highly desirable for hydrogen and oxygen evolution reactions. Herein, a series of phosphorus-doped Fe7S8 nanowires integrated within carbon (P-Fe7S8@C) are rationally synthesized via a one-step phosphorization of one-dimensional (1D) Fe-based organic-inorganic nanowires. The as-obtained P-Fe7S8@C catalysts with modified electronic configurations present typical porous structure, providing plentiful active sites for rapid reaction kinetics. Density functional calculations demonstrate that the doping Fe7S8 with P can effectively enhance the electron density of Fe7S8 around the Fermi level and weaken the Fe-H bonding, leading to the decrease of adsorption free energy barrier on active sites. As a result, the optimal catalyst of P-Fe7S8-600@C exhibits a relatively low overpotential of 136 mV for hydrogen evolution reaction (HER) to reach the current density of 10 mA/cm2, and a significantly low overpotential of 210 mV for oxygen evolution reaction (OER) at 20 mA/cm2 in alkaline media. The work presented here may pave the way to design and synthesis of other prominent Fe-based catalysts for water splitting via electronic regulation.