Promoting nickel oxidation state transitions in single-layer NiFeB hydroxide nanosheets for efficient oxygen evolution

Promoting the formation of high-oxidation-state transition metal species in a hydroxide catalyst may improve its catalytic activity in the oxygen evolution reaction, which remains difficult to achieve with current synthetic strategies. Herein, we present a synthesis of single-layer NiFeB hydroxide nanosheets and demonstrate the efficacy of electron-deficient boron in promoting the formation of high-oxidation-state Ni for improved oxygen evolution activity. Raman spectroscopy, X-ray absorption spectroscopy, and electrochemical analyses show that incorporation of B into a NiFe hydroxide causes a cathodic shift of the Ni2+(OH)(2) -> Ni3+delta OOH transition potential. Density functional theory calculations suggest an elevated oxidation state for Ni and decreased energy barriers for the reaction with the NiFeB hydroxide catalyst. Consequently, a current density of 100 mA cm(-2) was achieved in 1 M KOH at an overpotential of 252 mV, placing it among the best Ni-based catalysts for this reaction. This work opens new opportunities in electronic engineering of metal hydroxides (or oxides) for efficient oxygen evolution in water-splitting applications.

Automated summary

This article presents a synthesis method for single-layer NiFeB hydroxide nanosheets and demonstrates the effectiveness of electron-deficient boron in promoting the formation of high-oxidation-state Ni for improved oxygen evolution activity. Experimental results show that the incorporation of boron into a NiFe hydroxide can cause a cathodic shift of the Ni2+(OH)(2) -> Ni3+delta OOH transition potential and reduce the energy barriers for the reaction. As a result, the catalyst achieves a current density of 100 mA cm(-2) in 1 M KOH and is among the best Ni-based catalysts for this reaction.