Self-powered electrochemical glucose sensing enabled by zirconium holmium oxide/MXene/graphene nanocomposites with...

Advanced wearable electronics and self-powered diagnostic devices require electrode materials that can combine efficient energy storage with reliable biosensing. This study reports a multifunctional zirconium holmium oxide/titanium carbide MXene/graphene composite, denoted as ZrHo₂O₄/Ti₃C₂T_x MXene/graphene, synthesized by a hydrothermal method and evaluated as an electrode for hybrid supercapacitor performance and non-enzymatic glucose detection. Structural, surface, and morphological analyses confirmed the integration of crystalline ZrHo₂O₄ with conductive Ti₃C₂T_x-MXene and graphene, producing a porous and interconnected architecture favorable for charge transport and electrochemical activity. The ZrHo₂O₄/Ti₃C₂T_x MXene/graphene electrode demonstrated a specific capacity (Qs) of 315.22 C g^-1. When assembled with activated carbon as a battery-type hybrid supercapacitor, the device achieved a Qs of 315.22 C g^-1, an energy density of 35.94 Wh kg^-1, and a power density of 1275 W kg^-1, while retaining 88% of its capacity after 5000 cycles. For glucose sensing in phosphate-buffered saline, the modified electrode exhibited a linear response from 0.1 μM to 1.6 mM, a sensitivity of 5.1 μA mM^-1 cm^-2, and a detection limit of 0.03 μM. It also revealed a 15 s response time, selectivity against common interfering species, reproducibility, and signal stability. These results demonstrate that ZrHo₂O₄/Ti₃C₂T_x-MXene/graphene is a promising dual-function electrode for integrated energy-storage and glucose-sensing platforms in wearable and point-of-care devices.