Tailoring OER/ORR activity in TM₁N₄ catalysts through first-/second-shell nitrogen doping: a density functional...

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Optimizing catalyst reaction potentials is critical for improving catalytic performance.
• Metal-nitrogen-carbon (M-N-C) active centers, such as FeN4, CoN4, and NiN4, are promising for electrochemical reactions.
• Tailoring the electronic and atomic structure of active sites is essential for enhanced catalytic activity.

Purpose of the Study:

• To investigate the effect of nitrogen dopants in the first and second shells of M1N4 active centers on oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) potentials.
• To develop an effective modification strategy for optimizing catalyst reaction potentials.
• To enhance the catalytic performance of Fe1N4, Co1N4, and Ni1N4 active centers.

Main Methods:

• Utilized density functional theory (DFT) simulations to systematically study the impact of nitrogen dopants.
• Analyzed the effects of first- and second-shell nitrogen dopants on local atomic/electronic structures.
• Compared the catalytic activities and reaction potentials of modified M1N4 active centers.

Main Results:

• First-shell nitrogen dopants significantly influenced reaction potentials, while second-shell dopants provided fine-tuning.
• Combined regulation of nitrogen dopants in both shells effectively lowered OER and ORR overpotentials.
• N3-doped Fe1-pyrrole N4 and N2-doped Fe1-pyridine N4 exhibited the lowest overpotentials (209 mV for OER, 196 mV for ORR).

Conclusions:

• The strategic placement of nitrogen dopants in both the first and second shells is a viable approach to optimize catalyst performance.
• This dual-shell doping strategy significantly enhances catalytic activity for OER and ORR.
• The findings provide a promising pathway for designing highly efficient electrocatalysts.