Facet Effects Enhance Formic Acid Oxidation by Regulating Subsurface Interstitial Nitrogen Occupation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Direct formic acid fuel cells (DFAFCs) offer high energy density for portable electronics.
• Efficient anode catalysts are crucial for DFAFC commercialization due to the complex formic acid oxidation (FAO) pathway.

Purpose of the Study:

• To enhance palladium-based catalyst performance for FAO in DFAFCs.
• To investigate the effect of facet-controlled nitrogen occupation on catalytic activity and stability.

Main Methods:

• Synthesis of nitrogen-doped palladium nanocubes (PdN NCs) and cuboctahedrons (PdN COs).
• Theoretical calculations and experimental analyses to study nitrogen occupation sites and FAO mechanisms.

Main Results:

• Subsurface octahedral (O) site nitrogen occupation on the (100) facet of PdN NCs reduces the FAO energy barrier, enhancing activity.
• Tetrahedral (T) site nitrogen occupation on the (111) facet of PdN COs mitigates CO poisoning, improving stability.

Conclusions:

• Facet effect-regulated nitrogen occupation is a viable strategy for designing advanced DFAFC anode catalysts.
• This study provides insights into optimizing catalyst design for efficient formic acid oxidation.