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

Abstract

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.