Engineering Cu/NiCu LDH Heterostructure Nanosheet Arrays for Highly-Efficient Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic water splitting is vital for sustainable hydrogen production.
• Bimetallic layered double hydroxides (LDHs) are promising electrocatalysts for the oxygen evolution reaction (OER).
• NiCu LDH offers good stability but lacks sufficient OER activity compared to NiFe LDH.

Purpose of the Study:

• To design and synthesize a highly active and stable electrocatalyst for the oxygen evolution reaction (OER).
• To enhance the catalytic performance of NiCu LDH by incorporating copper nanoparticles.
• To investigate the electronic interactions and their effect on OER activity.

Main Methods:

• Synthesis of a Cu/NiCu LDH heterostructure electrocatalyst.
• Electrochemical characterization including over-potential and Tafel slope measurements.
• X-ray photoelectron spectroscopy (XPS) for surface analysis.
• Density functional theory (DFT) calculations for mechanistic insights.

Main Results:

• The Cu/NiCu LDH electrocatalyst exhibited a low over-potential of 206 mV and a Tafel slope of 86.9 mV dec⁻¹ at 10 mA cm⁻².
• The catalyst maintained performance for 70 hours at a high current density of 100 mA cm⁻² in 1M KOH.
• XPS revealed strong electronic interactions between Cu nanoparticles and NiCu LDH.
• DFT calculations indicated improved conductivity and optimized adsorption energies due to electronic coupling.

Conclusions:

• Copper nanoparticle modification significantly enhances the OER activity and stability of NiCu LDH.
• The improved performance is attributed to the electronic coupling between Cu nanoparticles and the NiCu LDH support.
• This work presents a promising strategy for developing advanced electrocatalysts for water splitting.