Optimizing charge pathways by interface engineering in Fe2O3/Co3O4/Co(PO3)2 heterostructures for superior oxygen evolution reaction

The Oxygen Evolution Reaction (OER) is vital for energy conversion and storage. This study presents a multi-heterostructure catalyst, Fe₂O₃/Co₃O₄/Co(PO₃)₂, created by encapsulating Fe ions in COF/MOF pores through grinding and one-step pyrolysis. The catalyst demonstrates exceptional OER performance, achieving an ultra-low overpotential of 232 mV, outperforming the Co₃O₄/Co(PO₃)₂ single heterostructure. The unique design significantly reduces electron transfer resistance (Rct = 5.88 Ω), enhancing electron transfer efficiency at the heterojunction interface. Additionally, the catalyst's increased specific surface area and mesoporosity boost the number of active catalytic sites. Density functional theory (DFT) studies reveal that optimized geometric structures and altered electron density around Co and Fe sites shift the d-band center, facilitating electron migration and improving adsorption and desorption processes. This research provides novel insights into creating high-efficiency OER electrocatalysts with heterogeneous interfaces, advancing sustainable energy technologies.