Single-Atom-Embedded Nitrogen-Doped Graphene as Efficient Electrocatalysts for the CO₂ Reduction Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Single-atom catalysts (SACs) offer high activity and selectivity for electrochemical CO2 reduction.
• Nitrogen-doped graphene is a promising support material for single-atom catalysts.

Purpose of the Study:

• To systematically evaluate metal single atoms on nitrogen-doped graphene (M-N4G) as electrocatalysts for CO2 reduction.
• To identify descriptors for predicting CO2RR catalyst performance.

Main Methods:

• Density functional theory (DFT) calculations were employed to investigate M-N4G (M = In, Tl, Ge, Sn, Pb, Sb, Bi).
• Electrocatalytic performance and selectivity for CO2 reduction versus hydrogen evolution were assessed.
• The adsorption energy of the *HCOO intermediate was used as a descriptor.

Main Results:

• Most M-N4G catalysts demonstrated higher selectivity for CO2 reduction over hydrogen evolution reaction (HER).
• Ge/Pb-N4G catalysts showed excellent performance for formic acid (HCOOH) generation with low limiting potentials (-0.292 and -0.306 V).
• The adsorption energy of *HCOO effectively predicts CO2RR catalyst reactivity.

Conclusions:

• M-N4G materials are highly effective electrocatalysts for CO2 reduction.
• Ge/Pb-N4G presents a superior catalytic system for HCOOH production.
• Catalyst design can be guided by intermediate adsorption energy descriptors.