Transition metal (Fe, Co, Mn, Cu) containing nitrogen-doped porous carbon as efficient oxygen reduction electrocatalysts for anion exchange membrane fuel cells

Delving into highly active and cost-efficient electrocatalysts for oxygen reduction reaction (ORR) is crucial for the large-scale application of polymer electrolyte fuel cells. Anion exchange membrane fuel cells (AEMFCs) are promising clean energy devices owing to their mild reaction conditions and the high probability of employing Pt-free catalysts for ORR. Developing the promising non-Pt ORR catalysts for AEMFC is still of great importance. Herein, we report the transition metal (Fe, Co, Mn, and Cu) impregnated melamine-phloroglucinol-formaldehyde (MPF) polymeric networks to derive metal-nitrogen-carbon (M-N-C) electrocatalysts via a robust synthesis route. The catalysts are screened through variable metal contents and different pyrolysis temperature optimi-zations by virtue of their ORR activity. The controlled synthesis method resulted to the prominent textural properties of the catalysts with efficient active centers to enhance the ORR performance. Amongst, iron-doped (MPF/Fe), and cobalt-doped (MPF/Co) catalysts are performing better in terms of half-wave potential (E1/2) values of 0.81 and 0.80 V vs RHE which is attributed to the highly active M-Nx sites and hierarchical porous structure of catalysts. Outstanding electrochemical stability in half-cell and high-power density in an AEMFC (up to 347 mW cm-2) made the present work drive to the development of highly efficient M-N-C catalysts for fuel cell applications.

Automated summary

Delving into highly active and cost-efficient electrocatalysts for oxygen reduction reaction (ORR) is crucial for large-scale application of polymer electrolyte fuel cells. Anion exchange membrane fuel cells (AEMFCs) are promising clean energy devices with mild reaction conditions and the possibility of employing Pt-free catalysts for ORR. This study focuses on the development of non-Pt catalysts for AEMFC by preparing metal-nitrogen-carbon (M-N-C) electrocatalysts through a robust synthesis method using transition metal impregnated melamine-phloroglucinol-formaldehyde (MPF) polymeric networks. The catalysts with optimized metal content and pyrolysis temperature showed enhanced ORR performance due to their prominent textural properties and efficient active centers. Iron-doped (MPF/Fe) and cobalt-doped (MPF/Co) catalysts performed the best with half-wave potential (E1/2) values of 0.81 and 0.80 V vs RHE, attributed to the highly active M-Nx sites and hierarchical porous structure. The outstanding electrochemical stability and high-power density in AEMFC (up to 347 mW cm-2) demonstrate the potential of these M-N-C catalysts for fuel cell applications.