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

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The oxygen evolution reaction (OER) is crucial for water splitting but limited by inefficient catalysts.
• Achieving high-oxidation-state transition metals in hydroxide catalysts is key to improving OER activity.
• Current synthetic strategies struggle to effectively promote these high-oxidation states.

Purpose of the Study:

• To synthesize single-layer NiFeB hydroxide nanosheets.
• To investigate the role of electron-deficient boron in promoting high-oxidation-state nickel.
• To enhance catalytic activity for the oxygen evolution reaction.

Main Methods:

• Synthesis of single-layer NiFeB hydroxide nanosheets.
• Raman spectroscopy and X-ray absorption spectroscopy for material characterization.
• Electrochemical analyses and Density Functional Theory (DFT) calculations to assess catalytic performance and mechanism.

Main Results:

• Boron incorporation shifted the Ni2+→Ni3+δ transition potential cathodically.
• DFT calculations indicated an elevated Ni oxidation state and reduced energy barriers.
• Achieved a current density of 100 mA cm−2 at 252 mV overpotential in 1 M KOH.

Conclusions:

• Electron-deficient boron effectively promotes high-oxidation-state Ni in NiFeB hydroxide catalysts.
• The synthesized catalyst demonstrates superior OER activity, comparable to the best Ni-based catalysts.
• This work presents a novel approach for electronic engineering of metal hydroxides for efficient water splitting.