Tailoring Ni-Fe-B Electronic Effects in Layered Double Hydroxides for Enhanced Oxygen Evolution Activity

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Nickel-iron layered double hydroxides (NiFe LDHs) are advanced catalysts for oxygen evolution reaction (OER) in alkaline environments.
• Despite their effectiveness, NiFe LDHs exhibit significant overpotentials, limiting their application.
• Developing strategies to enhance OER kinetics and reduce overpotentials is crucial for efficient energy conversion.

Purpose of the Study:

• To investigate the impact of quantitative boron (B) doping on the OER performance of NiFe LDHs.
• To tailor the electronic interactions between Ni, Fe, and B within the LDH structure.
• To optimize B doping levels for improved catalytic activity and efficiency.

Main Methods:

• Co-hydrolysis synthesis of NiFe LDHs with varying B doping concentrations (0% to 20.3%).
• Characterization of B-doped NiFe LDHs to confirm doping and analyze electronic structure.
• Electrochemical evaluation of OER performance, including overpotential and current density measurements.

Main Results:

• Boron doping effectively modifies the electronic properties of NiFe LDHs.
• Electron-deficient B acts as an electron sink, facilitating Ni2+ to Ni3+δ transition and accelerating OER kinetics up to 13.5% doping.
• Excessive B doping (13.5-20.3%) creates oxygen vacancies, hindering Ni2+ to Ni3+δ transition and reducing activity.
• Optimal B doping at 13.5% yields an overpotential of 208 mV at 500 mA cm⁻², positioning it as a highly effective OER catalyst.

Conclusions:

• Quantitative B doping is a viable strategy for electronic engineering of NiFe LDHs to enhance OER.
• The optimal B doping level balances electronic effects to maximize catalytic activity.
• This work provides a pathway for developing high-performance anode catalysts for water-splitting hydrogen production.