Application of Quantum Mechanical Density Functional Theory as a Fundamental Basis for Microkinetic Modeling of Catalytic Combustion

摘要

We have recently proposed a methodology for construction of detailed catalytic reaction mechanisms. Input parameters are the heats of chemisorption of adsorbed species, which are obtained either from experimental data or semi-empirical techniques, such as the Bond Order Conservation (BOC) theory. Experimental data for heats of chemisorption of radicals are not usually available, and therefore, the accuracy of BOC calculations cannot be assessed. In this paper, we present first principles quantum mechanical calculations using GGA level density functional theory (DFT) (B3LYP), for the most likely intermediate species in methane oxidation on a clean Pt surface. The Pt(111) catalyst surface is approximated as a Pt~(12) (8,4) bilayer cluster. Good agreement with experimental values for methane oxidation on Pt is found for many cases. Furthermore, we also discuss how DFT in combination with the semi-empirical BOC theory and transition state theory (TST) can be used as a fundamental basis in the development of surface reaction mechanisms for catalytic combustion. Insight into the methane decomposition paths is also presented.