Interfacial charge transfer engineering in S-ZIF-L@MIL-53/NF heterostructures for enhanced oxygen evolution kinetics

The development of cost-effective and efficient electrocatalysts for the oxygen evolution reaction (OER) is critical for advancing sustainable hydrogen production via water electrolysis. Herein, an innovative synthesis technique has been developed to fabricate leaf-like ZIF-L architectures on vertically aligned MIL-53 nanoarrays. This approach integrates in situ-grown MIL-53(Fe) nanosheets with sulfur-modified ZIF-L (S-ZIF-L), synergistically enhancing interfacial charge transfer dynamics while optimizing active site accessibility. The S-ZIF-L@MIL-53/NF catalyst demonstrates exceptional OER performance in an alkaline medium, achieving an ultralow overpotential of 336 mV at 500 mA cm−2. Remarkably, it exhibits robust stability for 300 h at 350 mA cm−2. In situ characterization reveals the coexistence of adsorbate evolution and lattice oxygen-mediated mechanisms, which collectively govern intermediate adsorption energetics and reaction kinetics. The sulfur-doping-induced morphological modulation and oxygen vacancy enrichment further contribute to enhanced electronic conductivity and catalytic activity. This work establishes a high-performance electrocatalytic platform through metal–organic framework heterojunction engineering and defect control, providing fundamental insights into interfacial charge transfer processes for sustainable energy technologies.