Gold Nanoparticle-Modified Nickel–Iron Coatings for Efficient Sodium Borohydride Electrooxidation

Sodium borohydride is regarded as a potential alternative fuel for direct liquid fuel cells due to its high energy density and ease of handling. However, the efficient electrooxidation of sodium borohydride (BOR) requires the development of advanced electrocatalysts with high activity, low cost, and long-term stability. Transition metal-based catalysts, particularly nickel–iron alloys, have shown considerable promise due to their affordability and favourable catalytic properties. This study explores the synergistic effects of gold and nickel–iron components in achieving high current densities and low overpotentials, which makes these materials promising for applications in direct borohydride fuel cells (DBFCs) and energy storage systems. Herein, we investigate the fabrication, characterization, and electrocatalytic properties of nickel–iron (Ni-Fe) coatings decorated with gold nanoparticles (AuNPs) for BOR. The objective of incorporating AuNPs onto Ni-Fe coatings is to enhance their catalytic activity and stability. Ni-Fe coatings were prepared using two techniques: electroless metal plating and galvanic displacement.

It was determined that AuNPs of a few nanometers in size were deposited on the NiFe coatings through the immersion of a NiFe/Cu electrode in a gold-containing solution for various periods. The BOR was evaluated in 0.05 M and 1 M NaOH solution using cyclic voltammetry and chronoamperometry. The fabricated NiFe catalysts with different AuNP loadings demonstrated significantly higher electrocatalytic activity towards the BOR as compared to bare Au or NiFe/Ti. This indicates the potential of AuNP-decorated NiFe coatings as a promising material for BOR in DBFC applications.

Acknowledgement

This research was funded by a grant (No. P-MIP-23-467) from the Research Council of Lithuania.