Mechanism Analysis of Catalytic Reactions Based on Density Functional Theory

Abstract

Reaction mechanism and elementary processes become more important in catalysis as well as combustion. In this article, we will introduce how to construct and analyze the reaction mechanism of catalytic reactions based on density functional theory (DFT), using examples from our recent study for steam methane reforming with nickel catalysts. Important energies on surface, such as adsorption, activation, and reaction energies, can be theoretically calculated using a slab model with periodic boundary conditions. Gibbs free energies and rate coefficients of elementary reactions is also calculated by phonon analysis based on DFT. Microkinetic simulations with constructed reaction mechanism enable us to compare directly with experimental results, for example, conversion, selectivity, and temperature profile in a fixed bed reactor filled with catalyst pellets. Detailed reaction mechanism analyses clarify the main reaction pathway and rate limiting step on surface. Finally, our latest study for the reactivity at the defects on surface will be shown as an example of future prospects for kinetic modeling in catalysis.