Non enzymatic hydrogen peroxide detection at ruthenium oxide–gold nano particle–Nafion modified electrode

We demonstrated non-enzymatic detection of hydrogen peroxide (H2O2) at ruthenium oxide gold nano particle (RuO2–AuNP)–Nafion modified glassy carbon electrode in phosphate buffer. Porous RuO2 is embedded in the Nafion matrix, and the AuNPs are deposited by electrochemical reduction of tetrachloroaurate. The efficient interaction between RuO2 and AuNP, and the higher crystallinity of the RuO2–AuNP is proven by the appearance of (1 1 1) and (2 2 0) planes in the X-ray diffraction pattern of the RuO2–AuNPs that are found in addition to the (1 0 1) and (2 1 1) planes in the patterns of pure RuO2. Increased fractions (atomic percents) of Ru and Au are confirmed in energy dispersive X-ray spectroscopy. High-resolution scanning electron microscopy and atomic force microscopy (AFM) indicate the controlled deposition of the AuNPs on the RuO2 nanoparticles protruding the Nafion film. The composite reduces the H2O2 at −0.14 V (vs. Ag/AgCl). The composite behavior is compared with the Nafion–AuNP and Nafion–RuO2 composites. Examination of solution pH and H2O2 concentration revealed enzyme mimetic behavior of the Nafion–RuO2–AuNP and showed 20 times higher Michaelis–Menten kinetic constant KM (10.1 mM) than the previously reported MnO2 based non-enzymatic H2O2 sensor. The composite is highly selective in presence of potential interferences such as ascorbic acid, uric acid, catechol and dopamine. The sensors showed a dynamic range of 0.1 nM to 30 mM per liter with the lowest detection limit 0.1 × 10−9 M. The method is used to determine the concentration of H2O2 in an antiseptic solution.