Single-Atom Alloys for the Electrochemical Oxygen Reduction Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Single-atom alloys (SAAs) combine the high activity of dopant transition metals with the selectivity of coinage metal hosts.
• SAAs are being explored as advanced electrocatalysts for various chemical reactions.

Purpose of the Study:

• Investigate single-atom alloys (SAAs) of Ni, Pd, Pt, Co, and Rh doped into Ag and Au hosts.
• Evaluate their potential as electrocatalysts for the oxygen reduction reaction (ORR) in proton-exchange membrane (PEM) fuel cells.

Main Methods:

• Density functional theory (DFT) calculations were employed.
• Theoretical overpotential, selectivity, and CO-poisoning tolerance were assessed.

Main Results:

• The Palladium-Gold (PdAu) SAA demonstrated a lower theoretical overpotential than Pt(111).
• PdAu SAA exhibited enhanced selectivity for the 4-electron ORR pathway.
• PdAu SAA showed improved tolerance to CO-poisoning compared to Pt(111).

Conclusions:

• Despite having fewer active sites than Pt(111), PdAu SAA's favorable properties suggest comparable catalytic performance.
• PdAu SAAs represent a viable alternative material for electrocatalytic ORR in PEM fuel cells.