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

We demonstrated non-enzymatic detection of hydrogen peroxide (H 2 O 2 ) at ruthenium oxide gold nano particle (RuO 2 –AuNP)–Nafion modified glassy carbon electrode in phosphate buffer. Porous RuO 2 is embedded in the Nafion matrix, and the AuNPs are deposited by electrochemical reduction of tetrachloroaurate. The efficient interaction between RuO 2 and AuNP, and the higher crystallinity of the RuO 2 –AuNP is proven by the appearance of (1 1 1) and (2 2 0) planes in the X-ray diffraction pattern of the RuO 2 –AuNPs that are found in addition to the (1 0 1) and (2 1 1) planes in the patterns of pure RuO 2. 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 RuO 2 nanoparticles protruding the Nafion film. The composite reduces the H 2 O 2 at −0.14 V (vs. Ag/AgCl). The composite behavior is compared with the Nafion–AuNP and Nafion–RuO 2 composites. Examination of solution pH and H 2 O 2 concentration revealed enzyme mimetic behavior of the Nafion–RuO 2 –AuNP and showed 20 times higher Michaelis–Menten kinetic constant K M (10.1 mM) than the previously reported MnO 2 based non-enzymatic H 2 O 2 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 H 2 O 2 in an antiseptic solution.