The paper studies the transfer of the oxygen atom O from the NO2 molecule to the CO molecule, resulting in the formation of CO2. The methods of quantum mechanics are used to obtain transition states, vibrational frequencies and reaction paths CO + NO2 <-> CO2 + NO, and their key energy characteristics. Two mechanisms of the reaction are determined: a direct one and a stepwise involving the formation of a stable intermediate complex. The rate constants of forward and backward reactions were calculated within the framework of the transition state theory. They are compared with the experimental data available in the references. Their approximations are presented in the form of Arrhenius in a wide temperature range of 300-2500 K.