A high-performance NiPMg ternary anode catalyst for direct borohydride fuel cells

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Direct borohydride fuel cells (DBFCs) offer high energy density and rapid startup.
• Developing high-performance, cost-efficient anode catalysts remains a key challenge for DBFC technology.

Purpose of the Study:

• To synthesize and investigate an amorphous NiPMg ternary catalyst for direct borohydride oxidation reaction (BOR).
• To explore the effect of magnesium incorporation on catalyst activity, selectivity, and stability.
• To evaluate the performance of the NiPMg catalyst in a DBFC.

Main Methods:

• Amorphous NiPMg ternary catalyst synthesized via constant potential electrodeposition.
• Systematic investigation of catalyst structure, morphology, and electrochemical performance.
• Density Functional Theory (DFT) calculations to understand reaction mechanisms and energy barriers.

Main Results:

• Magnesium introduction significantly enhances catalyst intrinsic activity and reactant adsorption.
• Effective inhibition of nickel oxidation and hydrogen evolution reaction (HER).
• Substantial reduction in the reaction energy barrier for the rate-determining step (RDS) of BOR.
• NiPMg catalyst demonstrates excellent activity, selectivity, and stability for BOR.

Conclusions:

• The NiPMg catalyst exhibits superior performance in DBFCs, achieving a peak power density of 484 mW cm^-2 and 1.92 V open-circuit voltage.
• Stable operation for 40 hours at 50 mA cm^-2 highlights the catalyst's durability.
• This work presents a promising design strategy for cost-effective, nonprecious metal anode catalysts for DBFCs.