Constructing atomically-dispersed Mn on ZIF-derived nitrogen-doped carbon for boosting oxygen reduction

Area of Science:

• Electrochemistry
• Materials Science
• Nanotechnology

Background:

• Platinum-based nanomaterials are crucial for oxygen reduction reaction (ORR) catalysis but are expensive.
• Developing cost-effective and highly active non-noble-metal alternatives is essential for widespread ORR applications.
• Single-atom catalysts offer unique properties for enhanced catalytic performance.

Purpose of the Study:

• To synthesize and characterize atomically dispersed manganese (Mn) atoms on ZIF-derived nitrogen-doped carbon frameworks (Mn-N_x/NC).
• To evaluate the electrocatalytic activity of Mn-N_x/NC for the oxygen reduction reaction (ORR).
• To investigate the potential of Mn-N_x/NC as a non-noble-metal catalyst for ORR.

Main Methods:

• Stepwise pyrolysis of ZIF-derived precursors to create nitrogen-doped carbon frameworks.
• Incorporation of atomically dispersed Mn atoms onto the carbon framework, forming Mn-N_x active sites.
• Electrochemical characterization, including cyclic voltammetry and rotating disk electrode measurements, to assess ORR activity.

Main Results:

• The synthesized Mn-N_x/NC exhibited superior electrocatalytic activity for ORR compared to pure nitrogen-doped carbon (NC).
• Mn-N_x/NC demonstrated a higher half-wave potential (E_1/2 = 0.88 V) and a modest Tafel slope (90 mV dec^-1).
• The enhanced performance is attributed to the unique Mn-N_x active sites facilitating intermediate adsorption.

Conclusions:

• Atomically dispersed Mn atoms on nitrogen-doped carbon frameworks (Mn-N_x/NC) are effective non-noble-metal catalysts for ORR.
• The Mn-N_x/NC catalyst offers a promising, cost-effective alternative to platinum-based materials.
• This study presents a facile synthetic route for single-atom catalysts applicable to ORR.