Triangular Trinuclear Metal-N₄ Complexes with High Electrocatalytic Activity for Oxygen Reduction

Abstract

A new class of macrocyclic metal-N(4) complexes [MN(4)](n) (M = Co and Fe) were designed and synthesized based on a triangular ligand. Their unique triangular trinuclear structure provides a high density of active sites and facilitates the reduction of dioxygen via a four-electron pathway. Among them, a [CoN(4)](3)/C catalyst (20 wt %) exhibits high catalytic activity and long-time stability for the oxygen reduction reaction (ORR) in alkaline conditions, superior to the commercial Pt/C catalyst. Such structurally well-defined [MN(4)](n) complexes provide a platform for a new generation of nonprecious metal catalysts (NPMCs) for fuel cell applications.

Systematic study of transition-metal (Fe, Co, Ni, Cu) phthalocyanines as electrocatalysts for oxygen reduction and their evaluation by DFT

“…4 To break down the price barrier for large-scale commercialization of the fuel cell technologies, non-precious metal catalysts have attracted much attention in the development of low-cost and efficient electrocatalysts for ORR. 5,6 Since Jasinki's discovery that cobalt phthalocyanine exhibited the outstanding performance for the ORR in 1967, 7,8 similar metal macrocyclic compounds are widely studied as alternative ORR catalysts, 9,10 in virtue of their low price and abundant supply compared to Pt. 11 As one of the important transition-metal macrocyclic compounds, transition-metal phthalocyanine (TMPc) attracts increasing concern as significant electrocatalyst for ORR.…”

DFT Study of the Oxygen Reduction Reaction Activity on Fe−N4-Patched Carbon Nanotubes: The Influence of the Diameter and Length

“…It was proposed that the active sites are the Fe ions coordinated by four nitrogen atoms, which are incorporated to graphitic carbon and have the same local structure of Fe-porphyrin catalysts [5]. These Fe−N 4 /C catalytic sites in graphitic carbon matrix were demonstrated to have excellent ORR catalytic performance [2,6,7,8,9]. Recently, graphene- and carbon nanotube (CNT)-based ORR catalysts containing transition metal and nitrogen attracted much research interest due to their excellent ORR activities [10,11,12,13].…”

Graphene as a Target for Polymer Synthesis

“…The mechanism of graphene formation is unclear [280], and a synthetic organic chemist might look down at such a "cook-and-bake" method as hopelessly undefined, but it has proven capable of producing large quantities of graphene [279,281,282]. It should be mentioned that we have also synthesized perfectly defined organometal complexes such as 45 as catalysts for oxygen reduction [283]. They function as catalysts in their own right, but also serve as model systems to optimize the desired four-electron transfer in oxygen reduction in pyrolytically formed materials (Fig.…”