Discrimination of a chemical kinetic mechanism for heterogeneously catalyzed reactions using intraparticle diffusion

Several kinetic models implying different kinetic schemes of a heterogeneous catalytic reaction may equally fit the experimental kinetic data. The fitting procedures performed in the frame of different kinetic models may yield equally physically meaningful values of the kinetics constants so that the different mechanisms cannot be discriminated against using these values. As a consequence, the selection of an appropriate kinetic scheme is a complicated task. In this paper, we present an intraparticle diffusion approach to discrimination between plausible kinetic schemes. This approach is based on the analysis of the effectiveness factor. It is demonstrated that the effectiveness factor follows significantly different trends for the kinetic models with identical reaction rates. Therefore, the kinetic scheme may be easily discriminated via consequent investigation of the process rate under reaction-rate control and internal diffusion control, which may be achieved by simply changing the catalyst particle size.

Automated summary

Different kinetic models can fit experimental data equally well, but cannot be distinguished based on the values of kinetics constants. This paper proposes an intraparticle diffusion approach to discriminate between kinetic models by analyzing the effectiveness factor. By investigating the process rate under reaction-rate control and internal diffusion control, the kinetic scheme can be easily distinguished.