Sustainable Synthesis of Amine-Anchored, Electronically Coupled Fe and Mn Single-Atom Catalysts for Synergistic Oxygen Reduction in Energy Conversion Applications Publisher



Sanaei D ; Dehghani M H ; Hosseini R ; Mirzaloo E ; Allam N K ; Hosseini S S ; Arcibar Orozco J A ; Javid A
Source: Sustainable Energy and Fuels Published:2026

Abstract

Stabilizing isolated metal atoms on sustainable and porous matrices is a challenging strategy with the potential to maximize the density of active sites and prevent agglomeration. In this study the controlled synthesis of atomically dispersed Fe and Mn single-atom catalysts on a nitrogen-doped hierarchical CO2-activated porous carbon fiber (NHPCFB) via coordination with –NH2 groups of chitosan is reported. During pyrolysis, the lone-pair electrons of the chitosan amines interact with the d-orbitals of Fe and Mn precursors, enabling uniform adsorption and stabilization of isolated metal centers within the porous carbon framework. Density functional theory (DFT) calculations and experimental analyses revealed that excessive Mn incorporation disrupts Fe–Nx active sites due to preferential Mn–Fe or Mn–Mn interactions, whereas low Mn loading enhances catalytic activity by synergistically modulating the Fe3+–N4 centers. The optimized SA Fe–Mn/NH2–NHPCFB catalyst with low Mn loading delivers reasonable ORR performance, including an onset potential of 0.95 V, a kinetic current density of 12.84 mA cm−2, and an average faradaic efficiency of 8% for H2O2 production, while retaining 96% of its current density after 50 000 s of continuous operation. This work establishes a versatile and sustainable strategy for anchoring spatially isolated but electronically coupled single-atom sites on bio-derived carbon matrices, offering new insights into the rational design of high-performance electrocatalysts for energy conversion. This journal is © The Royal Society of Chemistry, 2026.