MOF-derived porous UiO-66-co9S8@NCNT nanocomposite for high-performance supercapattery systems and electrocatalytic hydrogen evolution

초록

A ternary UiO-66-Co9S8@NCNT nanocomposite was synthesized as a multifunctional electrode material for asymmetric supercapattery and hydrogen evolution reaction (HER) applications. The hybrid design integrates the structural framework of UiO-66, redox-active Co9S8, and conductive nitrogen-doped carbon nanotubes (NCNTs). UiO-66 provides accessible porous channels for electrolyte penetration, Co9S8 contributes Faradaic redox sites and HER-active centers, and NCNTs improve electrical conductivity and structural stability. Owing to these synergistic effects, the UiO-66-Co9S8@NCNT electrode delivered a specific capacity of 1797C g- 1 at 10 mV s-1 and 2559C g- 1 at 2 A g- 1 in a three-electrode system. The assembled UiO-66-Co9S8@NCNT//AC asymmetric supercapattery device achieved a specific capacity of 415C g-1, a maximum energy density of 71.2 Wh kg- 1 at a power density of 1723 W kg-1, and 86.2% capacity retention after 5000 cycles. For alkaline HER, the composite required an overpotential of 260.45 mV to reach 10 mA cm- 2 and showed a Tafel slope of 77.11 mV dec-1. The improved performance is attributed to the combined effects of porous ion-accessible pathways, electroactive sulfide sites, and a conductive NCNT network. These results indicate that UiO-66-Co9S8@NCNT is a promising multifunctional material for next-generation energy storage and hydrogen-production systems.

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