MOF-derived MIL-53(Al)@KTi2(PO4)3@rGO ternary heterostructure as a bifunctional electrode for high-performance hybrid supercapacitors and hydrogen evolution

A MIL-53(Al)@KTi 2 (PO 4 ) 3 @rGO was successfully synthesized through hydrothermal and modified Hummers' methods. • The integration of porous MIL-53(Al) and conductive rGO enhanced charge transport and electroactive site accessibility. • The MIL-53(Al)@KTi 2 (PO 4 ) 3 @rGO electrode delivered a high specific capacity of 1189.23C g −1 . • The hybrid SC achieved an energy density of 45 Wh kg −1 and a power density of 2773 W kg −1 . • The ternary electrode showed a low overpotential of 46 mV and a Tafel slope of 49 mV dec −1 . The rising requirement of sustainable and multifunctional electrodes for energy storage and production has stimulated significant interest in advanced electrode architectures. In this study, a MIL-53(Al)@KTi 2 (PO 4 ) 3 @rGO composite was fabricated by means of combined hydrothermal and modified Hummers approach. The composite was rationally designed by integrating the MIL-53(Al), the favorable ionic transport characteristics of NASICON-type KTi 2 (PO 4 ) 3 , and the highly conductive network of rGO, there by promoting efficient charge and ion transport. Electrochemical evaluation in a three-electrode cell demonstrated a high specific capacity of 1189.23C g −1 . When assembled into a two-electrode supercapacitor device, the material delivered an energy density of 45 Wh kg −1 at a power density of 2773 W kg −1 . The device also maintained 92% of its initial capacity with a Coulombic efficiency of 97% after 10,000 consecutive charge–discharge cycles, indicating strong electrochemical durability. In addition to its energy storage performance, the MIL-53(Al)@KTi 2 (PO 4 ) 3 @rGO electrode demonstrated promising catalytic activity for the hydrogen evolution reaction, requiring only 46 mV overpotential to achieve the targeted current density and exhibiting a Tafel slope of 49 mV dec −1 . These results highlight the synergistic contribution of the MOF, NASICON phosphate, and rGO components and establish MIL-53(Al)@KTi 2 (PO 4 ) 3 @rGO as a promising multifunctional platform for advanced supercapacitor systems and electrocatalytic hydrogen production.