Rational design of high-performance low-loading oxygen reduction catalysts for alkaline fuel cells.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Advancing alkaline fuel cells is hindered by poor understanding of alkaline electrolytes and the slow oxygen reduction reaction.
• Developing effective catalyst design principles is crucial for improving fuel cell efficiency.

Purpose of the Study:

• To design and synthesize a highly active and stable catalyst for the oxygen reduction reaction in alkaline electrolytes.
• To investigate the structure-activity relationships governing catalyst performance.

Main Methods:

• Utilized a modified volcano plot approach for rational catalyst design.
• Synthesized platinum (Pt) nanosheets on palladium hydride (PdHₓ) nanosheet substrates.
• Employed spectroscopic, electrochemical, and electron microscopic characterization techniques.

Main Results:

• The designed Pt/PdHₓ catalyst demonstrated a 49-fold increase in specific activity compared to the benchmark Pt/C catalyst.
• Achieved high stability with a specific activity of 1.71 mA cm⁻² at 0.95 V vs. RHE.
• Observed performance enhancement attributed to tensile-strained Pt{111} facets, enhancing oxidative stability and reducing carbon corrosion.

Conclusions:

• The developed catalyst significantly surpasses U.S. Department of Energy targets for platinum group metal loading and cost.
• This study offers valuable insights into catalyst design strategies for the alkaline oxygen reduction reaction.
• The findings pave the way for more efficient and cost-effective alkaline fuel cells.