A comparative study of LHHW and ER kinetic models for NO oxidation over Co₃O₄ catalyst

Experimental data for the NO oxidation to NO₂ at atmospheric pressure over Co₃O₄ catalyst were subjected to various kinetic rate models. The power law kinetics, Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetics, and Eley-Rideal (ER) kinetics were employed to suggest a possible reaction mechanism and a suitable kinetic rate equation. The kinetic rate equation based on the LHHW kinetics with adsorption of NO as the rate-controlling step and the kinetic rate equation based on the ER kinetics with surface reaction as the rate-limiting step were first equivalently found as the best-fit kinetic rate equations. In each case similar activation energies were resulted and that the oxygen adsorption was found inhibiting the rate of the oxidation reaction. However, the final discrimination based on the literature findings suggested the ER model as the best-fit kinetic model with activation energy of 58.3 kJ/mol and enthalpy of dissociative adsorption of oxygen as -2.10 kJ/mol.