Basic Kinetic Models of Catalytic Heterogenous Reactions

2 Basic Kinetic Models of Catalytic Heterogenous Reactions 

In general, a mechanism for any complex reaction (catalytic or non-catalytic) is defined as a sequence of elementary steps involved in the overall transformation. To determine these steps and especially to find their kinetic parameters is very rare if at all possible. It requires sophisticated spectroscopic methods and/or computational tools. Therefore, a common way to construct a microkinetic model describing the overall transformation rate is to assume a simplified reaction mechanism that is based on experimental findings. Once the model is chosen, a rate expression can be obtained and fitted to the kinetics observed. 

Some basic models often used for heterogenous catalytic reactions are described and the overall rate expressions are developed. 

Langmulr-HInshelwood Model The main assumption of this model is that the catalytic reaction proceeds only via chemical adsorption of all reactants on the catalytic surface and the transformation takes place as a series of surface reactions 

Let s first consider a monomolecular transformation, like the catalytic isomerization of hydrocarbons, as a simple example. 

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