Theoretical modeling: a new tool for heterogeneous catalysis

Heterogeneous catalysis handles complex objects and systems. The reactant must follow several steps for its chemical transformation in the catalyst: diffusion in a porous media, interaction with the catalyst, chemical reaction, desorption and diffusion out of the catalyst structure. Several theoretical approaches can today be proposed in order to model these various processes. Diffusion problems can be tackled by classical molecular dynamics or Monte-Carlo simulations. In recent studies such techniques have been applied to phase transition phenomena in confined porous systems. The detailed atomic structure of the catalyst and the interaction with reactant molecules require quantum methods, allowing a numerical resolution of the Schrodinger equation. New algorithms and codes, based on density functional theory, enable the scientists to accurately model systems with hundreds of atoms, hence opening the way to a realistic modeling of catalytic systems. Several examples are shown, related with catalytic materials or processes: the structure of a deposit of palladium on nickel, the reactions pathways for NO dissociation on metal surfaces, the reactivity of subsurface hydrogen atoms for hydrogenation reaction, and the structure of iron doped polyoxometalates.