FeVOOH@MnO[sbnd]NC hollow-porous composites exhibiting robust versatile catalysis for oxygen electrode reactions

초록

Oxygen electrode processes, including the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), are pivotal for sustainable energy conversion technologies, highlighting the need to develop cost-effective, high-efficiency, and durable non-precious metal catalysts. In this study, we designed a composite catalyst, FeVOOH@MnO–NC, by integrating Fe-doped VOOH hollow nanospheres (FeVOOH) with MnO–nitrogen-doped carbon (MnO–NC) and evaluated its bifunctional performance for OER and ORR. The incorporation of Fe into VOOH promoted structural evolution and increased oxygen vacancy concentration, contributing to enhanced catalytic activity. Meanwhile, the MnO–NC framework provided abundant active sites and facilitated rapid electron transfer through its conductive and porous architecture. FeVOOH@MnO–NC composites, synthesized with varying mass ratios (1:2, 1:1, 2:1, 3:1), were systematically characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy to elucidate their structural and electronic properties. Electrochemical measurements revealed that the optimized FeVOOH@MnO–NC composite exhibited superior ORR performance with a high half-wave potential of 0.956 V, surpassing commercial Pt/C, while demonstrating a lower OER overpotential than RuO2 under identical test conditions. Furthermore, the composite exhibited excellent stability over 1000 CV cycles as well as superior methanol tolerance compared to Pt/C, suggesting its potential for direct methanol fuel cell (DMFC) applications. These results highlight the promise of FeVOOH@MnO–NC as a cost-effective bifunctional catalyst for next-generation energy conversion systems. © 2025

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