Hierarchical-Pore-Stabilization Strategy for Fabricating 18.3 wt% High-Loading Single-Atom Catalyst for Oxygen...

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Metal single-atom catalysts (M-SACs) offer 100% atomic utilization for reactions like the oxygen reduction reaction (ORR).
• Low metal loading in M-SACs typically below 2 wt% hinders their overall catalytic performance.
• Developing high-loading M-SACs is crucial for enhancing catalytic efficiency.

Purpose of the Study:

• To report a hierarchical-structure-stabilization strategy for fabricating high-loading M-SACs.
• To achieve efficient ORR activity using the developed high-loading M-SACs.
• To explore the potential of this strategy for broader catalytic applications.

Main Methods:

• Fabrication of M-SACs using a hierarchical pore structure generated by SiO2 with high nitrogen content.
• Utilizing mesoporous and confinement effects to stabilize Fe atoms during pyrolysis.
• Introducing Selenium (Se) to modulate the electronic structure of Fe-N4 sites.

Main Results:

• Achieved a high metal loading of 18.3% for the M-SACs.
• The synthesized Fe single-atom catalyst demonstrated high ORR activity with half-wave potentials of 0.895 V (KOH) and 0.791 V (HClO4).
• The strategy effectively boosted the density and accessibility of Fe-N4 active sites.

Conclusions:

• A hierarchical-pore-stabilization strategy effectively enhances the loading and performance of M-SACs.
• The high-loading Fe-SACs exhibit significant ORR activity, paving the way for advanced catalytic applications.
• This approach offers a new pathway for designing high-performance M-SACs for thermocatalysis and photocatalysis.