Background Rao et al. |
The authors have defined 15 reactions to occur: Langmuir-Hinshelwood form of kinetics is used for most of the heterogeneous reactions while Arrhenius-type kinetics (with the assumption of reactions being elementary) is used for the oxygen storage reactions (reactions 10 – 15). Let’s look at reaction 5; CO + NO goes to CO where S is the catalyst substrate and the subscript ADS indicates that the molecule is adsorbed at the surface. As the theory states, the rate limiting step is the reaction of the adsorbed molecules (low the probability of two molecules colliding), and this should give the rate equation: where K, K The authors end up with this rate equation: So, what are the differences, and why? As one can see, the Cs disappears and an exponential term is introduced in the numerator, while the denominator has gained two extra factors. The disappearance of the Cs can be explained by that the R The exponential factor exp(-E The two extra factors in the denominator are due to the complexity of the total reaction. The ideal RLH doesn’t take into account the other reactions occurring at the same time in the catalyst. The factors are due to the inhibition of the CO, C A full listing of the reaction rate equations in this paper can be seen below. |