Surface oxysulfide-engineered Fe₂O₃/α-MoO₃ heterostructure for efficient oxygen evolution in anion exchange membrane water electrolysis

초록

Anion-exchange membrane water electrolysis (AEMWE) has emerged as a promising technology for sustainable hydrogen production due to its potential for low-cost operation and high product purity. However, the sluggish kinetics of the oxygen evolution reaction (OER) at the anode remain a critical bottleneck. Herein, we report a rationally engineered nano-heterostructured catalyst consisting of Fe₂O₃ nanoparticles (NPs) anchored on carbon black (CB)-supported MoOₓSᵧ-modified α-MoO₃ nanosheets for efficient OER and AEM water electrolysis. In this architecture, α-MoO₃ nanosheets serve as a stable catalytic scaffold, while surface MoOₓSᵧ species modulate the electronic structure and generate abundant defect sites, promoting favorable adsorption of oxygenated intermediates. CB provides a conductive network and structural support, facilitating rapid charge transport and preventing nanosheet aggregation. Meanwhile, Fe₂O₃ NPs act as highly active catalytic centers and are likely to undergo in situ transformation into Fe-based oxyhydroxide species under alkaline conditions, accelerating OER kinetics. Benefiting from these synergistic interactions, the optimized Fe₂O₃@CB_MoOₓSᵧ/α-MoO₃ catalyst exhibits excellent OER performance, delivering low overpotentials of 270 and 320 mV at 50 and 100 mA cm−2, respectively, together with stable operation for over 100 h under alkaline conditions. When integrated into an AEM water electrolyzer with Fe₂O₃@CB_MoOₓSᵧ/α-MoO₃ as the anode, the system achieves a current density of 1.78 A cm−2 at 2.0 V, maintains stable operation for 200 h at 500 mA cm−2, and exhibits hydrogen and oxygen Faradaic efficiencies of 95.12% and 97.91%, respectively. This work highlights the effectiveness of oxide–oxysulfide heterostructure engineering coupled with Fe-based active centers for developing high-performance and durable anode catalysts for practical AEM water electrolysis.

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