Computational Insight into TM-N Embedded Graphene Bifunctional Electrocatalysts for Oxygen Evolution and Reduction...

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• The global energy crisis necessitates advanced electrocatalysts for efficient energy conversion.
• Bifunctional electrocatalysts capable of both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are highly sought after.

Purpose of the Study:

• To investigate the bifunctional OER/ORR activity of metal (Co/Rh/Ir) and nitrogen co-doped graphene systems.
• To understand the role of nitrogen doping concentration on catalytic performance using first-principles calculations.

Main Methods:

• Systematic investigation of metal and N co-doped graphene (TM-N_x@G, x = 0, 2, 4) using first-principles calculations.
• Analysis of charge transfer and adsorption free energy of intermediates.
• Construction of a dual volcano plot using the descriptor ΔG_OH*.

Main Results:

• Charge transfer and intermediate adsorption free energy are key factors determining OER/ORR overpotentials.
• Systems with ΔG_OH* values between 0.40-0.70 eV exhibit excellent bifunctional catalytic activity.
• Identified optimal N-dopant concentrations for enhanced electrocatalytic performance.

Conclusions:

• Metal and nitrogen co-doped graphene are effective bifunctional electrocatalysts.
• The study provides a promising strategy for designing efficient OER/ORR electrocatalysts.
• Understanding descriptor-activity relationships is crucial for catalyst design.