Anodic Oxidation of Nitric Oxide on Au/Nafion®: Kinetics and Mass Transfer

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ISSN： 0021-891X

Source： Journal of Applied Electrochemistry, Vol.31, Iss.4, 2001-04, pp. : 437-443

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Abstract

The rate determining step for the anodic oxidation of nitric oxide on Au/Nafion^® was experimentally and theoretically found to beNO + Au → Au–NO_adsThe anodic oxidation of nitric oxide was first order with respect to nitric oxide. The reaction rate constant increased from 3.3×10^−5 to 9.6×10^−5cm s^−1 as the applied potential increased from 0.74 to 0.77V. The anodic oxidation of nitric oxide was controlled by the electrochemical kinetics when the anodic potential was less than 0.8 V. When the potential was greater than 1.0 V, it was located in the mass transfer region. The limiting current increased from 1184 to 1589μA with increase in gas flow rate from 250 to 750ml min^−1 when the potential was set at 1.05 V and the concentration of nitric oxide was 100 ppm. The diffusion resistance in the gas diffusion layer can be neglected for gas flow rates greater than 750 ml min^−1. The diffusivity of nitric oxide and the equivalent diffusion layer thickness within the porous electrode were evaluated to be 3.43×10^−4cm^2s^−1 and 0.051 cm, respectively.