Catalytic oxidation of acetone and ethanol on a platinum wire

The current-voltage characteristics of a thin long platinum wire in air with small admixtures of acetone or ethanol vapors were obtained. Using the quadratic dependence of platinum resistance on temperature, the temperature-current dependences for the wire were calculated. At concentrations of combustible gas vapors above a certain value, these dependences show a hysteretic character. Using the assumption of complete oxidation of acetone and ethanol on platinum, as a catalyst, and the first order of the oxidation reaction, an analysis of temperature-current dependences was performed. The temperature difference between the high and low-temperature stationary modes of catalytic oxidation on the wire makes it possible to estimate the concentration of the impurity in the mixture. As a result, the experimental dependence of the critical value of the catalytic current ignition and the extinguishing of the gas mixture on platinum on the impurity concentration was constructed. With its analytical description, it is possible to fairly accurately estimate the apparent values of the activation energy and the pre-exponential factor of the oxidation reaction in a wide temperature range. A method of determining the kinetic parameters of the oxidation reaction based on the experimentally found parameters of the degeneracy of critical conditions is proposed.