An efficient nickel hydrogen oxidation catalyst for hydroxide exchange membrane fuel cells

Area of Science:

• Electrochemistry
• Materials Science
• Energy Conversion

Background:

• Hydroxide exchange membrane fuel cells (HEMFCs) are a promising clean energy technology.
• The widespread adoption of HEMFCs is hindered by the reliance on costly platinum group metal (PGM) electrocatalysts, particularly for the hydrogen oxidation reaction (HOR).

Purpose of the Study:

• To develop and characterize a high-performance, PGM-free electrocatalyst for the HOR in HEMFCs.
• To investigate the fundamental properties of the Ni-based catalyst that contribute to its enhanced activity.

Main Methods:

• Synthesis of Ni nanoparticles embedded in a nitrogen-doped carbon support.
• Electrochemical characterization including measurement of electrochemical surface area-normalized exchange current density.
• Surface analysis using X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) and H2 chemisorption.

Main Results:

• The Ni-based catalyst achieved an electrochemical surface area-normalized exchange current density of 70 μA cm⁻², the highest reported for any PGM-free HOR catalyst.
• HEMFCs utilizing this catalyst demonstrated a peak power density of 488 mW cm⁻², a significant improvement over existing PGM-free systems.
• Spectroscopic and chemisorption data indicated that electronic interactions between Ni nanoparticles and the support optimize hydrogen and hydroxide binding energies.

Conclusions:

• The developed Ni-based catalyst represents a breakthrough in PGM-free HOR electrocatalysis.
• The findings demonstrate the feasibility of highly efficient and cost-effective HEMFCs without PGM reliance.
• This work opens new avenues for designing advanced electrocatalysts for fuel cell applications.