IL-derived N, S co-doped ordered mesoporous carbon for high-performance oxygen reduction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient and stable metal-free catalysts for the oxygen reduction reaction (ORR) is crucial for clean energy technologies.
• Ordered mesoporous carbon (OMC) offers a unique structure for catalyst design.
• Ionic liquids (ILs) can serve as precursors for doping carbon materials.

Purpose of the Study:

• To design and synthesize a highly efficient N, S co-doped porous carbon ORR catalyst.
• To investigate the synergistic effects of doping and mesoporous structure on ORR performance.
• To evaluate the catalyst's activity and stability compared to commercial benchmarks and explore further enhancements with metal doping.

Main Methods:

• Synthesis of N, S co-doped porous carbon using OMC as a template and ILs as dopants.
• Characterization of the synthesized IL/OMC (IOMC) nanostructure.
• Electrochemical evaluation of ORR activity and stability in 0.10 M KOH solution.
• Fe doping into IOMC to assess its impact on ORR performance in both basic and acidic media.

Main Results:

• The IOMC nanostructure exhibited high specific surface area and planar N, S doping.
• The N, S co-doped OMC catalyst demonstrated ORR activity and stability comparable to commercial Pt/C.
• The metal-free IOMC catalyst showed excellent performance, positioning it among the best carbon-based ORR catalysts.
• Fe doping significantly boosted the ORR activity in both basic and acidic solutions, highlighting the role of Fe in active site construction.

Conclusions:

• The synergistic effect of N, S doping and the ordered mesoporous structure is responsible for the high ORR activity.
• The developed IOMC material is a promising metal-free ORR catalyst with superior performance and stability.
• Transition metal Fe doping is critical for enhancing ORR activity, particularly in acidic electrolytes, suggesting Fe-containing sites are highly active.