Collective Effect in a Multicomponent Ensemble Combining Single Atoms and Nanoparticles for Efficient and Durable...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Single-atom catalysts (SACs) are promising for oxygen reduction reaction (ORR) but lack sufficient activity and durability.
• Non-noble metal SACs face challenges in practical application due to performance limitations.

Purpose of the Study:

• To investigate the collective effect in metal single-atom catalysts for enhanced ORR performance.
• To understand the interplay between different active sites and nanoparticles.
• To improve both catalytic activity and durability of non-noble metal catalysts.

Main Methods:

• Density Functional Theory (DFT) calculations to model catalytic systems.
• Machine Learning (ML) to analyze complex interactions and identify performance descriptors.
• Electrochemical testing to evaluate ORR activity and durability.

Main Results:

• An unexpected collective effect between FeN4OH sites, CeN4OH motifs, and Fe/Fe-CeO2 nanoparticles was identified.
• Enhanced ORR activity with a half-wave potential of 0.948 V vs RHE, outperforming commercial Pt/C (0.851 V vs RHE).
• Remarkable durability with negligible activity loss after 50,000 potential cycles due to shortened Fe-N bonds.

Conclusions:

• The collective effect significantly improves ORR activity and durability in non-noble metal catalysts.
• ML analysis revealed key descriptors for enhanced performance.
• The collective effect principle is broadly applicable to other transition metals (Co, Ni, Cu, Cr, Mn).