Heterogeneous Iridium Oxide/Gold Nanocluster for Non-enzymatic Glucose Sensing and pH Probing
Abstract
In this work, heterogeneous gold-doped iridium oxide nanoclusters (IrO2–Au NCs) that are both pH-sensitive and glucose-responsive were synthesized through electrospinning followed by high-temperature calcination. The as-prepared IrO2–Au NCs were systematically characterized using various advanced techniques including scanning electron microscopy, X-ray powder diffraction and Raman spectroscopy. They were then employed as the sensing element to fabricate a sensor for both non-enzymatic glucose sensing and solid-state pH monitoring. Sensing performance of the IrO2–Au NCs based dual sensor toward pH and glucose was evaluated using various electrochemical techniques, including potentiometric, cyclic voltammetry and amperometric techniques. The results show that the as-prepared IrO2–Au NCs not only maintain accurate and reversible pH sensitivity derived from IrO2, but also demonstrate good electrocatalytic activity resulted from Au toward glucose oxidation in alkaline medium at a low applied potential with a sensitivity of 21.20 mA·mM-1·cm-2, a limit of detection of 2.93 mM (S/N=3) and a reasonable selectivity against various interferences. These features show that the as-prepared IrO2–Au NCs hold great promise as a dual-functional sensing material for the development of a high-performance sensor for both solid-state pH and non-enzymatic glucose sensing.
