Coordination environment regulated spin states in Fe-N-C catalysts for efficient oxygen evolution reaction

Area of Science:

• Catalysis
• Materials Science
• Computational Chemistry

Background:

• Single-atom catalysts (SACs) are crucial for efficient electrocatalysis.
• Fe-N-C materials are promising SACs for the oxygen evolution reaction (OER).
• Understanding structure-activity relationships in Fe-N-C is key to catalyst design.

Purpose of the Study:

• To investigate the impact of coordination environments on Fe-N-C catalyst properties.
• To elucidate the relationship between spin states and OER activity.
• To provide theoretical guidance for designing high-performance Fe-based SACs.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Structural modulation of Fe-N-C coordination environments.
• Analysis of magnetic moments, spin density, and electronic structure (projected density of states).
• Calculation of Gibbs free energy for OER intermediates.

Main Results:

• Six distinct Fe-N-C structures were modeled, varying N and C coordination.
• Spin state classification and electronic structure differences were correlated with coordination.
• OER activity was linked to coordination environments via d-band electronic distribution.
• Microscopic mechanisms influencing OER activity were elucidated.

Conclusions:

• Coordination environment significantly impacts Fe spin states and OER activity in Fe-N-C catalysts.
• D-band electronic distribution modulation is the key mechanism linking structure to OER performance.
• DFT provides a theoretical framework for designing advanced Fe-based single-atom OER catalysts.