Plasma-driven synthesis of amorphous/crystalline carbon-encapsulated Fe/MnO nanoclusters for efficient oxygen...

The development of high-performance, non-precious metal electrocatalysts for the oxygen evolution reaction (OER) is crucial for sustainable energy conversion. Herein, we report a rapid one-step synthesis of ternary Fe/MnO nanoclusters uniformly encapsulated within an amorphous/crystalline carbon matrix (FMC) via a direct current arc plasma method. This unique core-shell architecture emerges from the extreme temperature (∼10⁴ K) and millisecond-scale rapid quenching inherent to the plasma process, characterized by a highly graphitized outer carbon layer and an inner defective carbon region. The as-synthesized FMC catalyst exhibits outstanding OER activity in alkaline media, requiring a low overpotential of only 317 mV to achieve 10 mA cm^-2, with a small Tafel slope of 104.1 mV dec^-1, comparable with commercial RuO₂ and most reported transition metal-based catalysts. Comprehensive experimental studies and density functional theory (DFT) calculations reveal that the superior performance originates from the synergistic interplay of three key factors, strong electronic coupling between Fe and MnO that optimizes the adsorption of oxygen intermediates, the carbon layer that prevents nanoparticle aggregation and ensures durability, and the hybrid amorphous/crystalline carbon matrix that facilitates charge and mass transport. This work provides a novel strategy for designing efficient multi-component electrocatalysts through non-equilibrium synthesis.