Self-assembly strategy for Co/N-doped meso/microporous carbon toward superior oxygen reduction catalysts

Proton-exchange-membrane fuel cells (PEMFCs) are of considerable interest as a sustainable, renewable, efficient, and eco-friendly electrochemical conversion systems of energy. Sluggish oxygen reduction reaction (ORR) as the cathodic reaction have mainly dragged down the PEMFCs in practical use. The most effective catalyst for ORR today is a Pt-based catalyst, which have a high scarcity value and low durability for methanol. Therefore, major efforts have recently been devoted to exploring transition metal and hetero-atom doped carbon materials in fuel cells for large-scale and commercial applications. Herein, we report a facile synthesis route of Co-N doped meso/microporous carbon catalysts (Co/N/MPC-act) via self-assembly of resorcinol-based resin, triblock copolymer and Co containing ionic liquid followed by CO2 activation. The obtained catalyst exhibited outstanding oxygen reduction activity in an alkaline medium. It yields an onset potential of 0.960 V (vs. RHE) and a limiting current density of 5.0 mA/cm2, which are comparable to that of the commercial Pt/C catalyst. This high activity is contributed by the combination of inter-connected meso/microporous structures and highly dispersed CoNx species with metallic Co. The Co/N/MPC-act catalyst exhibited excellent long-term operation stability and methanol tolerance, making it a promising non-precious metal-based ORR catalyst for PEMFCs.

Automated summary

Proton-exchange-membrane fuel cells (PEMFCs) are sustainable, renewable, efficient, and eco-friendly energy conversion systems, but their performance is hindered by sluggish oxygen reduction reactions. Recent efforts have been focused on exploring transition metal and hetero-atom doped carbon materials, with Co-N doped meso/microporous carbon catalysts showing outstanding oxygen reduction activity in an alkaline medium. This catalyst exhibits high activity, long-term stability, and methanol tolerance, making it a promising non-precious metal-based ORR catalyst for PEMFCs.