Interface-engineered nickel borate in metal-organic framework-derived electrode for stable water oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient and stable electrocatalysts for the oxygen evolution reaction (OER) is crucial for energy conversion technologies.
• Existing catalysts often suffer from poor stability and activity under demanding operational conditions.

Purpose of the Study:

• To construct self-supported OER electrodes with enhanced activity and durability using an interface engineering strategy.
• To introduce Ni₃(BO₃)₂ as an interfacial bonding enhancer for a robust electrode architecture.

Main Methods:

• Fabrication of a three-tiered electrode architecture: substrate-Ni₃(BO₃)₂ interface-self-reconstructed metal-organic framework (MOF)-derived active layer.
• Electrochemical characterization to evaluate OER performance (overpotentials at specific current densities).
• Long-term stability testing at high current density.
• Theoretical calculations (e.g., DFT) to understand interfacial bonding and electronic structure.

Main Results:

• The MOOH-MOF/BNF electrode achieved low overpotentials of 207 mV and 268 mV at 10 and 100 mA cm⁻², respectively.
• Demonstrated remarkable long-term durability, maintaining stable potential during 500 h of continuous operation at 100 mA cm⁻².
• Theoretical analysis revealed optimized electronic environments and strengthened NiO bond covalency due to Ni₃(BO₃)₂ modification, forming strong NiOB bonds.

Conclusions:

• The strong NiOB interfacial bonding acts as a 'chemical rivet', anchoring the catalytic layer and optimizing charge transfer for structural integrity.
• This interface engineering principle enables the rational design of efficient and durable electrocatalytic electrodes.
• The study provides a new strategy for constructing robust interfaces in electrocatalysis.