Variable-valence ion and heterointerface accelerated electron transfer kinetics of electrochemical water splitting

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 1; no. 23; pp. 12391 - 12399
• Main Authors: Lu, Mengfei, Kong, Shaoxi, Yan, Shicheng, Zhou, Peng, Yu, Tao, Zou, Zhigang
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 14.06.2022
• Subjects: Coupling; Electrochemistry; Electron transfer; Electrons; Heterojunctions; Hydrogen evolution reactions; Intermediates; Kinetics; Nanoalloys; Nitrides; Oxygen; Oxygen evolution reactions; Splitting; Water splitting
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d1ta11011j

Accelerating electron transfer kinetics is an efficient strategy to tackle the sluggish oxygen evolution reaction (OER). Herein, Ni 3 Fe 1− x V x /Ni 3 Fe 1− x V x N heterojunctions were elaborately constructed to demonstrate that the coupling of variable-valence metal doping and nanoalloy/nitride heterointerfaces could optimize the OER performance of antiperovskite nitrides. The spectroscopic results suggested that during OER electrochemical surface reconstruction occurred to form an assembly of a crystalline Ni 3 Fe 1− x V x /Ni 3 Fe 1− x V x N heterojunction core and amorphous NiFeOOH shell (Ni 3 Fe 1− x V x /Ni 3 Fe 1− x V x N@NiFeOOH). The electron transfer from the OER intermediates via the amorphous NiFeOOH shell was efficiently accelerated by the variable-valence V 3+/4+ electron acceptor at the core@shell interface and the heterojunction effect in the Ni 3 Fe 1− x V x /Ni 3 Fe 1− x V x N core. As a result, the oxygen and hydrogen evolution reactions can occur at low overpotentials of 260 mV at 50 mA cm −2 and 113 mV at 10 mA cm −2 , respectively, affording a low cell voltage of 1.66 V at 10 mA cm −2 for water splitting in alkaline electrolyte (1.0 M KOH). Our results provide a new attempt at improving water splitting kinetics via the variable-valence ion coupling heterojunction effect. The electron transfer from OER intermediates via the amorphous NiFeOOH shell was efficiently accelerated by the variable-valence V 3+/4+ acceptor at core@shell interface and the heterojunction effect in Ni 3 Fe 1− x V x /Ni 3 Fe 1− x V x N core, significantly facilitating the OER performance.