Synergistic MIL-53/VCT MXene@NiFeO heterostructure for advanced energy storage and hydrogen evolution applications

초록

A ternary MIL-53/V2CTx@NiFe2O4 heterostructure was developed as a bifunctional electrode material for remarkable supercapattery energy storage and alkaline hydrogen evolution reaction (HER). The material design integrates the porous ion-accessible framework of MIL-53, the conductive layered network of V2CTx MXene, and the redox/catalytic activity of spinel NiFe2O4. This synergistic architecture improves electrolyte penetration, accelerates electron transport, exposes abundant Ni/Fe redox-active sites, and enhances interfacial charge-transfer kinetics. Structural and physicochemical analysis confirmed the effective formation of the MIL-53/V2CTx@NiFe2O4 heterostructure; BET and EIS results revealed an increased specific surface area of 99.68 m2 g(-)1 and reduced charge-transfer resistance of 58 Omega. In the three-electrode configuration, the MIL-53/V2CTx@NiFe2O4 shows a CV-derived specific capacity (Q s) of 960 C g(-)1 at 10 mV s(-)1 and a GCD-derived Q s of 1210 C g(-)1 at 2 A g(-)1, confirming its enhanced Faradaic charge-storage capability. Assembled MIL-53/V2CTx@NiFe2O4//AC asymmetric supercapattery achieved an energy and power density of 87.4 Wh kg(-)1, 1700 W kg(-)1, and retained 83.6% of its capacity after 12000 cycles with 93.4% coulombic efficiency. Dunn's kinetic analysis further confirmed the coexistence of diffusion-controlled battery-type and surface-controlled capacitive contributions. For alkaline HER, the composite exhibited improved catalytic activity with an overpotential of 174.8 mV and a Tafel slope of 76.4 mV dec(-)1, attributed to MXene-assisted conductivity, improved interfacial electron transfer, and accessible Ni/Fe catalytic sites. These results demonstrate that MIL-53/V2CTx@NiFe2O4 is a promising bifunctional heterostructure for advanced hydrogen generation and electrolytic energy-storage applications.

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