Structural Self-Regulation-Promoted NO Electroreduction on Single Atoms.

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Single-atom catalysts (SACs) offer high efficiency but face challenges with low atom loading and activity limitations due to scaling relationships.
• Existing methods struggle to simultaneously increase both the loading and intrinsic activity of single atoms (SAs) in catalysts.

Purpose of the Study:

• To theoretically design a novel single-atom catalyst with simultaneously enhanced loading and activity.
• To overcome the adsorption-energy scaling relationships that typically limit SA catalyst performance.
• To develop a catalyst capable of efficient nitrogen oxide (NO) to ammonia (NH3) conversion.

Main Methods:

• Theoretical design of a two-step structural self-regulation process for catalyst generation.
• Utilizing divacancies in graphene to anchor single atoms from transition metal supports (dv-g/TM).
• Employing adsorbate-assisted, reversible vacancy migration to dynamically tune SA coordination environments.

Main Results:

• Achieved high loading of single atoms (SAs) through thermodynamic self-regulation via graphene divacancies.
• Circumvented traditional scaling relationships by dynamically altering SA coordination environments during kinetic self-regulation.
• The designed dv-g/Ni catalyst demonstrated efficient NO to NH3 conversion at a low limiting potential of -0.25 V vs RHE.

Conclusions:

• The proposed two-step self-regulation strategy effectively enhances both SA loading and catalytic activity.
• The dv-g/Ni catalyst shows significant potential for practical applications in nitrogen oxide reduction.
• This work provides a new theoretical framework for designing advanced single-atom catalysts.