Reductive H₂O₂ Detection at Nanoparticle Iridium/Carbon Film Electrode and Its Application as L-Glutamate Enzyme Sensor

We prepared a thin film electrode consisting of a 3.3% atomic concentration of iridium nanoparticles dispersed in graphite-like carbon (Ir-NDC) by a simple RF sputtering method. The film structure was characterized by TEM, XPS and AFM. The TEM results showed that the Ir particles, whose average size was 2 nm, were homogenously dispersed in the carbon matrix. XPS revealed two chemical states of Ir (Ir(0) and Ir(IV)) in the film. The Ir-NDC film electrode exhibited excellent electrocatalytic ability with regard to H₂O₂ reduction with low atomic concentration compared to the bulk Ir electrode. The effect of L-ascorbic acid can be suppressed due to the reductive detection of hydrogen peroxide. We applied this electrode for enzymatic glutamate detection. At a detection potential of -0.15 V (vs. Ag/AgCl), we could measure the concentration of glutamate without interferences from ascorbic acid and oxygen.