A nanozyme–enzyme hybrid electrochemical platform based on CeO₂–MoS₂/Au for selective lactate monitoring in human sweat

This study reports a nanozyme-enhanced electrochemical platform for quantifying lactate in exercise-induced sweat, constructed by modifying a glassy carbon electrode with a CeO₂–MoS₂ composite decorated with Au nanoparticles and immobilized lactate oxidase. Structural characterization confirmed crystalline CeO₂ (8 nm) with mixed Ce³ ⁺/Ce⁴⁺ states, layered MoS₂ (0.62 nm spacing), and uniformly distributed AuNPs, forming a conductive, high-surface-area catalytic interface. The composite significantly reduced the H₂O₂ reduction overpotential, enabling sensor operation at 0.0 V vs Ag/AgCl and minimizing interference from coexisting sweat metabolites. Electrochemical impedance spectroscopy showed a reduction in charge transfer resistance from ∼580 Ω (bare electrode) to ∼220 Ω after nanozyme modification, supporting accelerated electron transport. The sensor exhibited rapid amperometric response (