Two-Dimensional Covalent Framework Derived Nonprecious Transition Metal Single-Atomic-Site Electrocatalyst toward...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing nonprecious metal catalysts for the oxygen reduction reaction (ORR) is crucial for efficient and affordable energy devices.
• Single-atomic-site catalysts (SASCs) offer maximum atomic utilization and precise structural control, making them promising for ORR.
• Controllable synthesis of SASCs is essential for optimizing their catalytic activity.

Purpose of the Study:

• To synthesize an ultrathin, two-dimensional (2D) single-atomic-site catalyst using a novel templated pyrolysis method.
• To evaluate the ORR performance of the synthesized iron-based SASCs (Fe-SASCs) in alkaline media.
• To assess the potential of Fe-SASCs as cathode catalysts in zinc-air batteries.

Main Methods:

• An organometallic framework template-assisted pyrolysis strategy was employed for catalyst synthesis.
• Electrochemical measurements were conducted to assess ORR activity, including half-wave potential and current density.
• Durability, methanol tolerance, and zinc-air battery performance were evaluated.

Main Results:

• The synthesized Fe-SASCs exhibited excellent ORR activity in alkaline media, with performance comparable to commercial Pt/C.
• Fe-SASCs demonstrated superior durability and methanol tolerance compared to Pt/C.
• As a cathode catalyst in a zinc-air battery, Fe-SASCs achieved a maximum power density of 142 mW cm⁻² and a current density of 235 mA cm⁻².

Conclusions:

• The organometallic framework templated pyrolysis is an effective strategy for synthesizing 2D Fe-SASCs.
• Fe-SASCs present a highly active, stable, and cost-effective alternative to platinum for ORR.
• The demonstrated performance in zinc-air batteries highlights the practical potential of Fe-SASCs for energy applications.