Nanostructured Ni-Cu Electrocatalysts for the Oxygen Evolution Reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Nickel-based materials are key electrocatalysts for the oxygen evolution reaction (OER) in alkaline media for water splitting.
• Developing efficient and durable nonprecious metal catalysts is crucial for advancing water-splitting technologies.

Purpose of the Study:

• To synthesize and characterize novel nickel-copper (Ni-Cu) nanoparticles and nanoclusters for OER electrocatalysis.
• To investigate the OER performance and durability of these Ni-Cu nanostructures.
• To elucidate the structure-activity relationship of Ni-Cu nanoclusters in OER.

Main Methods:

• Synthesis of Ni-Cu nanoparticles (20-50 nm) and nanoclusters (<20 atoms) using glutathione ligands.
• Characterization using matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometry.
• Electrochemical evaluation of OER activity and durability on carbon electrodes, with and without TiO2 modification.

Main Results:

• Successfully synthesized discrete heterobimetallic Ni-Cu nanoclusters.
• Ni-Cu nanoclusters (52:48 mol % Ni:Cu) exhibited a low OER onset overpotential (50 mV) and efficient performance (150 mV at 10 mA cm⁻²).
• Enhanced durability was achieved by immobilizing nanoclusters on TiO2-modified electrodes, with ligand aggregation dynamics observed via infrared spectroscopy.

Conclusions:

• Ni-Cu nanoclusters represent highly efficient, underexplored electrocatalysts for OER.
• The study provides insights into the reactivity and stability of these nanostructured catalysts.
• These findings offer a promising avenue for developing advanced nonprecious metal OER catalysts.