Atomic-Level Modulation of Electronic Density at Cobalt Single-Atom Sites Derived from Metal-Organic Frameworks: Enhanced Oxygen Reduction Performance

Demonstrated here is the correlation between atomic configuration induced electronic density of single-atom Co active sites and oxygen reduction reaction (ORR) performance by combining density-functional theory (DFT) calculations and electrochemical analysis. Guided by DFT calculations, a MOF-derived Co single-atom catalyst with the optimal Co-1-N3PS active moiety incorporated in a hollow carbon polyhedron (Co-1-N3PS/HC) was designed and synthesized. Co-1-N3PS/HC exhibits outstanding alkaline ORR activity with a half-wave potential of 0.920 V and superior ORR kinetics with record-level kinetic current density and an ultralow Tafel slope of 31 mV dec(-1), exceeding that of Pt/C and almost all non-precious ORR electrocatalysts. In acidic media the ORR kinetics of Co-1-N3PS/HC still surpasses that of Pt/C. This work offers atomic-level insight into the relationship between electronic density of the active site and catalytic properties, promoting rational design of efficient catalysts.

Automated summary

This study demonstrates the correlation between atomic configuration induced electronic density of single-atom Co active sites and oxygen reduction reaction (ORR) performance. The designed and synthesized Co-1-N3PS/HC catalyst shows outstanding ORR activity in alkaline and acidic media, surpassing Pt/C and most non-precious ORR electrocatalysts. Insights from this work promote rational design of efficient catalysts.