Metallic Ir-decorated iridium oxide nanofibers with programmable performance towards non-enzymatic detection of hydrogen peroxide

Hydrogen peroxide (H₂O₂) is an essential biomolecule in various fields, including clinical control and environmental protection. This present work reports a design of a non-enzymatic H₂O₂ electrochemical sensor. The metallic Ir-decorated iridium oxide nanofibers (IrO₂@Ir NFs) are prepared using the electrospinning process followed by annealing at different temperatures (500–900 °C). The resultant materials are characterized through field emission scanning electron microscopy, X-ray diffraction analysis, and X-ray absorption spectroscopy. Furthermore, the electrochemical sensing performance of the IrO₂@Ir NFs electrode is evaluated by cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometric (i-t) techniques. The sensitivity of the IrO₂@Ir NFs modified screen-printed electrode (SPCE) is checked to investigate the effect of annealing temperature on the H₂O₂ sensing. The performance of the nanofibers in the electro-reduction of H₂O₂ is programmable by controlling the metallic Ir contents. The IrO₂@Ir NFs electrode annealed at 600 °C (IrO₂@Ir-600 °C NFs) exhibits better electrocatalytic activity towards the electro-reduction of H₂O₂. Further, the broad linear range (0.1–1000 µM), low detection limit (LOD) of 0.16 µM with a higher sensitivity of 289 μA/cm²·mM is successfully achieved. Additionally, the IrO₂@Ir-600 °C NFs modified SPCE has appreciable selectivity in the presence of potentially interfering biological molecules and the practical applicability was demonstrated in MCF-7 human breast cancer cells.